CA2925170C

CA2925170C - Processes for preparing alumina and various other products

Info

Publication number: CA2925170C
Application number: CA2925170A
Authority: CA
Inventors: Richard Boudreault; Joel Fournier; Marie-Maxime LABRECQUE-GILBERT; Hubert Dumont; Jonathan BOUFFARD; Denis ARGUIN
Original assignee: Aem Technologies Inc
Current assignee: Aem Technologies Inc
Priority date: 2013-09-26
Filing date: 2014-09-26
Publication date: 2021-12-07
Anticipated expiration: 2034-09-26
Also published as: WO2015042692A1; CA2925170A1

Abstract

There is provided a process for preparing alumina. The process comprise leaching an aluminum-containing material (for example an industrial waste product chosen from red mud, fly ashes and a mixture thereof), with HCl so as to obtain a leachate comprising aluminum ions and a solid, and separating the solid from the leachate. Then, the process comprises reacting the leachate with HCl so as to obtain a liquid and a precipitate comprising the aluminum ions in the form of AlCl3, and separating the precipitate from the liquid. Then, the precipitate is reacted with a base. Finally, the process comprises heating the precipitate under conditions effective for converting the precipitate into Al2O3.

Description

PROCESSES FOR PREPARING ALUMINA AND VARIOUS OTHER
PRODUCTS
[0001] Intentionally blank.
TECHNICAL FIELD

[0002] The present disclosure relates to improvements in the field of chemistry applied to the production of alumina. For example, it relates to processes for the production of alumina via the extraction of aluminum from aluminum-containing materials. These processes can also be efficient for preparing other products such as hematite, MgO, silica and oxides of various metals, sulphates and chlorides of various metals, as well as rare earth elements, rare metals and aluminum.
BACKGROUND OF THE DISCLOSURE

[0003] There have been several known processes for the production of alumina.
Many of them were using bauxite as starting material. These processes, that were mainly alkaline processes, have been employed throughout the years. Several of such alkaline processes have the disadvantage of being inefficient to segregate and extract value added secondary products, thus leaving an important environmental impact.
There have also been development work employing hydrochloric acid for the leaching step but, it has been found that such processes were not efficient for removing most part of the impurities and especially iron. For example, removal of iron was also difficult to be carried out via adequate and economical techniques especially when using continuous processes.
SUMMARY OF THE DISCLOSURE

[0004] According to one aspect, there is provided a process for preparing alumina, the process comprising :
leaching an aluminum-containing material, that is an industrial waste product chosen from red mud, fly ashes and a mixture thereof, with HCI so as to obtain Date Recue/Date Received 2021-04-01 a leachate comprising aluminum ions and a solid, and separating the solid from the leachate;
reacting the leachate with HCI so as to obtain a liquid and a precipitate comprising the aluminum ions in the form of AlC13, and separating the precipitate from the liquid;
reacting the precipitate with a base; and heating the precipitate under conditions effective for converting the precipitate into Al2O3.

[0005] According to another, there is provided a process for preparing alumina, the process comprising :
leaching an aluminum-containing material, that is an industrial waste product chosen from red mud, fly ashes and a mixture thereof, with an acid so as to obtain a leachate comprising aluminum ions and a solid, and separating the solid from the leachate;
reacting the leachate with HCI so as to obtain a liquid and a precipitate comprising the aluminum ions in the form of AlC13, and separating the precipitate from the liquid;
reacting the precipitate with a base; and heating the precipitate under conditions effective for converting the precipitate into A1203.

[0006] According to another aspect, there is provided a process for preparing alumina, the process comprising:
leaching an aluminum-containing material, that is an industrial waste product chosen from red mud, fly ashes and a mixture thereof, with HCI so as to obtain a leachate comprising aluminum ions and a solid, and separating the solid from the leachate;

reacting the leachate with HCI so as to obtain a liquid and a precipitate comprising the aluminum ions in the form of AlC13, and separating the precipitate from the liquid;
optionally reacting the precipitate with a base; and heating the precipitate under conditions effective for converting the precipitate into A1203 and optionally recovering gaseous HCI so-produced.

[0007] According to another, there is provided a process for preparing alumina, the process comprising :
leaching an aluminum-containing material, that is an industrial waste product chosen from red mud, fly ashes and a mixture thereof, with an acid so as to obtain a leachate comprising aluminum ions and a solid, and separating the solid from the leachate;
reacting the leachate with HCI so as to obtain a liquid and a precipitate comprising the aluminum ions in the form of AlC13, and separating the precipitate from the liquid;
optionally reacting the precipitate with a base; and heating the precipitate under conditions effective for converting the precipitate into A1203 and optionally recovering gaseous HCI so-produced..

[0008] According to another aspect, there is provided a process for preparing alumina, the process comprising:
leaching an aluminum-containing material, that is an industrial waste product, with HCI so as to obtain a leachate comprising aluminum ions and a solid, and separating the solid from the leachate;
reacting the leachate with HCI so as to obtain a liquid and a precipitate comprising the aluminum ions in the form of AlC13, and separating the precipitate from the liquid;

reacting the precipitate with a base; and heating the precipitate under conditions effective for converting the precipitate into A1203.

[0009] According to another aspect, there is provided a process for preparing alumina, the process comprising:
leaching an aluminum-containing material, that is an industrial waste product, with an acid so as to obtain a leachate comprising aluminum ions and a solid, and separating the solid from the leachate;
reacting the leachate with HCI so as to obtain a liquid and a precipitate comprising the aluminum ions in the form of AlC13, and separating the precipitate from the liquid;
reacting the precipitate with a base; and heating the precipitate under conditions effective for converting the precipitate into A1203.

[0010] According to another aspect, there is provided a process for preparing alumina, the process comprising:
leaching an aluminum-containing material, leaching an aluminum-containing material, that is an industrial waste product, with an acid so as to obtain a leachate comprising aluminum ions and a solid, and separating the solid from the leachate;
reacting the leachate with HC1 so as to obtain a liquid and a precipitate comprising the aluminum ions in the form of AlC13, and separating the precipitate from the liquid;
optionally reacting the precipitate with a base; and heating the precipitate under conditions effective for converting the precipitate into Al2O3 and optionally recovering gaseous HC1 so-produced.

[0011] According to another aspect, there is provided a process for preparing alumina and optionally other products, the process comprising:
leaching an aluminum-containing material with HCI so as to obtain a leachate comprising aluminum ions and a solid, and separating the solid from the leachate;
reacting the leachate with HCI so as to obtain a liquid and a precipitate comprising the aluminum ions in the form of AlC13, and separating the precipitate from the liquid;
heating the precipitate under conditions effective for converting AlC13 into Al2O3 and recovering gaseous HCI so-produced; and recycling the gaseous HCI so-produced by contacting it with water so as to obtain a composition having a concentration higher than HCI azeotrope concentration ( 20.2 weight %) and reacting the composition with a further quantity of aluminum-containing material so as to leaching it.

[0012] According to another aspect, there is provided a process for preparing alumina and optionally other products, the process comprising :
leaching an aluminum-containing material with HCI so as to obtain a leachate comprising aluminum ions and a solid, and separating the solid from the .
leachate;
reacting the leachate with HCI so as to obtain a liquid and a precipitate comprising the aluminum ions in the form of AlC13, and separating the precipitate from the liquid;
heating the precipitate under conditions effective for converting AlC13 into A1203 and recovering gaseous HCI so-produced; and recycling the gaseous HCI so-produced by contacting it with water so as to obtain a composition having a concentration of about 18 to about 45 weight %
or about 25 to about 45 weight % and reacting the composition with a further quantity of aluminum-containing material so as to leaching it.

[0013] According to another aspect, there is provided a process for preparing alumina and optionally other products, the process comprising:
leaching an aluminum-containing material with HCI so as to obtain a leachate comprising aluminum ions and a solid, and separating the solid from the leachate;
reacting the leachate with HCl so as to obtain a liquid and a precipitate comprising the aluminum ions in the form of AlC13, and separating the precipitate from the liquid;
heating the precipitate under conditions effective for converting AlC13 into A1203 and recovering gaseous HCI so-produced; and recycling the gaseous HCI so-produced by contacting it with water so as to obtain a composition having a concentration of about 18 to about 45 weight %
or about 25 to about 45 weight % and using the composition for leaching the aluminum-containing material.

[0014] According to another aspect, there is provided a process for preparing alumina and optionally other products, the process comprising :
leaching an aluminum-containing material with HCI so as to obtain a leachate comprising aluminum ions and a solid, and separating the solid from the leachate;
reacting the leachate with HCI so as to obtain a liquid and a precipitate comprising the aluminum ions in the form of AICI3, and separating the precipitate from the liquid;
heating the precipitate under conditions effective for converting AlC13 into A1203 and recovering gaseous HCI so-produced; and recycling the gaseous HCI so-produced by contacting it with the leachate so as to precipitate the aluminum ions in the form of A1C13.6H20.

[0015] According to another aspect, there is provided a process for preparing alumina and optionally other products, the process comprising:
leaching an aluminum-containing material with HCI so as to obtain a leachate comprising aluminum ions and a solid, and separating the solid from the leachate;
reacting the leachate with HCI so as to obtain a liquid and a precipitate comprising the aluminum ions in the form of AlC13, and separating the precipitate from the liquid; and heating the precipitate under conditions effective for converting AlC13 into A1203.

[0016] According to another aspect, there is provided a process for preparing alumina and optionally other products, the process comprising :
leaching an aluminum-containing material with an acid so as to obtain a leachate comprising aluminum ions and a solid, and separating the solid from the leachate;
reacting the leachate with HCI so as to obtain a liquid and a precipitate comprising the aluminum ions in the form of AlC13, and separating the precipitate from the liquid; and heating the precipitate under conditions effective for converting AlC13 into Al2O3.

[0017] According to another aspect, there is provided a process for preparing alumina and optionally other products, the process comprising :
leaching an aluminum-containing material with HCI so as to obtain a leachate comprising aluminum ions and a solid, and separating the solid from the leachate;

reacting the leachate with HCI so as to obtain a liquid and a precipitate comprising the aluminum ions in the form of AlC13, and separating the precipitate from the liquid; and heating the precipitate under conditions effective for converting AlC13 into A1203 and optionally recovering gaseous HCI so-produced.

[0018] According to one aspect, there is provided a process for preparing alumina and optionally other products, the process comprising :
leaching an aluminum-containing material with HCI so as to obtain a leachate comprising aluminum ions and a solid, and separating the solid from the leachate;
reacting the leachate with HCI so as to obtain a liquid and a precipitate comprising the aluminum ions, and separating the precipitate from the liquid;
optionally reacting the precipitate with a base;
heating the precipitate under conditions effective for converting the precipitate into A1203 and optionally recovering gaseous HCI so-produced; and optionally recycling the gaseous HCl so-produced by contacting it with water so as to obtain a composition having a concentration higher than HCl azeotrope concentration ( 20.2 weight %) and reacting the composition with a further quantity of aluminum-containing material so as to leaching it.

[0019] According to one aspect, there is provided a process for preparing alumina and optionally other products, the process comprising :
leaching an aluminum-containing material with HCI so as to obtain a leachate comprising aluminum ions and a solid, and separating the solid from the leachate;
reacting the leachate with HCI so as to obtain a liquid and a precipitate comprising the aluminum ions, and separating the precipitate from the liquid;
optionally reacting the precipitate with a base;

heating the precipitate under conditions effective for converting the precipitate into A1203 and optionally recovering gaseous HC1 so-produced; and optionally recycling the gaseous HCI so-produced by contacting it with water so as to obtain a composition having a concentration higher than NCI
azeotrope concentration ( 20.2 weight A)) and reacting the composition with a further quantity of aluminum-containing material so as to leaching it.

[0020] According to one aspect, there is provided a process for preparing alumina and optionally other products, the process comprising :
leaching an aluminum-containing material with an acid so as to obtain a leachate comprising aluminum ions and a solid, and separating the solid from the leachate;
reacting the leachate with HCI so as to obtain a liquid and a precipitate comprising the aluminum ions, and separating the precipitate from the liquid;
optionally reacting the precipitate with a base;
heating the precipitate under conditions effective for converting the precipitate into A1203 and optionally recovering gaseous HCI so-produced; and optionally recycling the gaseous HCI so-produced by contacting it with water so as to obtain a composition having a concentration higher than HCI
azeotrope concentration ( 20.2 weight %) and reacting the composition with a further quantity of aluminum-containing material so as to leaching it.

[0021] According to another aspect, there is provided a process for preparing alumina and optionally other products, the process comprising :
leaching an aluminum-containing material with HCI so as to obtain a leachate comprising aluminum ions and a solid, and separating the solid from the leachate;

reacting the leachate with HCI so as to obtain a liquid and a precipitate comprising the aluminum ions in the form of AlC13, and separating the precipitate from the liquid;
optionally reacting the precipitate with a base;
heating the precipitate under conditions effective for converting the precipitate into A1203 and optionally recovering gaseous HCl so-produced; and optionally recycling the gaseous HCI so-produced by contacting it with water so as to obtain a composition having a concentration of about 18 to about 45 weight % or about 25 to about 45 weight % and reacting the composition with a further quantity of aluminum-containing material so as to leaching it.
=

[0022] According to another aspect, there is provided a process for preparing alumina and optionally other products, the process comprising :
leaching an aluminum-containing material with an acid so as to obtain a leachate comprising aluminum ions and a solid, and separating the solid from the leachate;
reacting the leachate with an HCI so as to obtain a liquid and a precipitate comprising the aluminum ions in the form of AlC13, and separating the precipitate from the liquid;
optionally reacting the precipitate with a base;
heating the precipitate under conditions effective for converting the precipitate into Al2O3 and optionally recovering gaseous HCI so-produced; and optionally recycling the gaseous HCI so-produced by contacting it with water so as to obtain a composition having a concentration of about 18 to about 45 weight % or about 25 to about 45 weight % and reacting the composition with a further quantity of aluminum-containing material so as to leaching it.

[0023] According to another aspect, there is provided a process for preparing alumina and optionally other products, the process comprising :

leaching an aluminum-containing material with HCI so as to obtain a leachate comprising aluminum ions and a solid, and separating the solid from the leachate;
reacting the leachate with HCI so as to obtain a liquid and a precipitate comprising the aluminum ions in the form of AlC13, and separating the precipitate from the liquid;
optionally reacting the precipitate with a base;
heating the precipitate under conditions effective for converting the precipitate into A1203 and optionally recovering gaseous HCI so-produced; and recycling the gaseous HCI so-produced by contacting it with water so as to obtain a composition having a concentration of about 18 to about 45 weight %
or about 25 to about 45 weight % and using the composition for leaching the aluminum-containing material.

[0024] According to another aspect, there is provided a process for preparing alumina and optionally other products, the process comprising :
=
leaching an aluminum-containing material with an acid so as to obtain a leachate comprising aluminum ions and a solid, and separating the solid from the leachate;
reacting the leachate with HCI so as to obtain a liquid and a precipitate comprising the aluminum ions in the form of AlC13, and separating the precipitate from the liquid;
optionally reacting the precipitate with a base;
heating the precipitate under conditions effective for converting the precipitate into A1203 and optionally recovering gaseous HCI so-produced; and recycling the gaseous HCI so-produced by contacting it with water so as to obtain a composition having a concentration of about 18 to about 45 weight %
or about

25 to about 45 weight % and using the composition for leaching the aluminum-containing material.
[0025] According to another aspect, there is provided a process for preparing alumina and optionally other products, the process comprising :
leaching an aluminum-containing material with HCI so as to obtain a leachate comprising aluminum ions and a solid, and separating the solid from the leachate;
reacting the leachate with HCl so as to obtain a liquid and a precipitate comprising the aluminum ions in the form of AlC13, and separating the precipitate from the liquid;
optionally reacting the precipitate with a base;
heating the precipitate under conditions effective for converting the precipitate into A1203 and optionally recovering gaseous HCI so-produced; and optionally recycling the gaseous HCI so-produced by contacting it with the leachate so as to precipitate the aluminum ions in the form of AlC13.6H20.

[0026] According to another aspect, there is provided a process for preparing alumina and optionally other products, the process comprising :
leaching an aluminum-containing material with an acid so as to obtain a leachate comprising aluminum ions and a solid, and separating the solid from the leachate;
reacting the leachate with HCI so as to obtain a liquid and a precipitate comprising the aluminum ions in the form of AlC13, and separating the precipitate from the liquid;
optionally reacting the precipitate with a base;
heating the precipitate under conditions effective for converting the precipitate into A1203 and optionally recovering gaseous HCI so-produced; and optionally recycling the gaseous HCI so-produced by contacting it with the leachate so as to precipitate the aluminum ions in the form of AlC13=6H20.

[0027] According to another aspect, there is provided a process for preparing alumina and optionally other products, the process comprising :
leaching an aluminum-containing material with HCI so as to obtain a leachate comprising aluminum ions and a solid, and separating the solid from the leachate;
reacting the leachate with HCI so as to obtain a liquid and a precipitate comprising the aluminum ions in the form of AlC13, and separating the precipitate from the liquid;
optionally reacting the precipitate with a base; and heating the precipitate under conditions effective for converting the precipitate into Al2O3.

[0028] According to another aspect, there is provided a process for preparing alumina and optionally other products, the process comprising :
leaching an aluminum-containing material with an acid so as to obtain a leachate comprising aluminum ions and a solid, and separating the solid from the leachate;
reacting the leachate with HCI so as to obtain a liquid and a precipitate comprising the aluminum ions in the form of AlC13, and separating the precipitate from the liquid;
optionally reacting the precipitate with a base; and heating the precipitate under conditions effective for converting the precipitate into A1203.

[0029] According to another aspect, there is provided a process for preparing alumina and optionally other products, the process comprising :

leaching an aluminum-containing material with HCl so as to obtain a leachate comprising aluminum ions and a solid, and separating the solid from the leachate;
reacting the leachate with HCI so as to obtain a liquid and a precipitate comprising the aluminum ions in the form of AlC13, and separating the precipitate from the liquid;
optionally reacting the precipitate with a base;
heating the precipitate under conditions effective for converting the precipitate into A1203 and optionally recovering gaseous HCI so-produced.

[0030] According to another aspect, there is provided a process for preparing alumina and optionally other products, the process comprising:
leaching an aluminum-containing material with an acid so as to obtain a leachate comprising aluminum ions and a solid, and separating the solid from the leachate;
reacting the leachate with HCI so as to obtain a liquid and a precipitate comprising the aluminum ions in the form of AlC13, and separating the precipitate from the liquid;
optionally reacting the precipitate with a base;
heating the precipitate under conditions effective for converting the precipitate into A1203 and optionally recovering gaseous HCI so-produced.

[0031] According to another aspect, there is provided a process for preparing aluminum comprising obtaining alumina according to a process as defined in the present disclosure and converting the alumina into aluminum.
BRIEF DESCRIPTION OF DRAWINGS

[0032] In the following drawings, which represent by way of example only, various embodiments of the disclosure:

July 2015 24-07-2015

[0033] Fig. 1 shows a block diagram of an example of process for preparing alumina and various other products according to the present disclosure;

[0034] Fig. 2 is an extraction curve for Al and Fe in which the extraction percentage is expressed as a function of a leaching time in a process according to an example of the present application;

[0035] Fig. 3 shows a block diagram of another example of process for preparing alumina and various other products according to the present disclosure;

[0036] Fig. 4 is a schematic representation of an example of a process for purifying/concentrating HCI according to the present disclosure;

[0037] Fig. 5 is a schematic representation of an example of a process for purifying/concentrating HCI according to the present disclosure;

[0038] Fig. 6 shows another block diagram of an example of process for preparing alumina and various other products according to the present disclosure;

[0039] Fig. 7 shows another block diagram of an example of process for preparing alumina and various other products according to the present disclosure;

[0040] Fig. 8 shows a block diagram of an example of process for preparing alumina and various other products according to the present disclosure; and

[0041] Fig. 9 shows a block diagram of another example of process for preparing alumina and various other products according to the present disclosure.
DETAILED DESCRIPTION OF VARIOUS EMBODIMENTS

[0042] The following non-limiting examples further illustrate the technology described in the present disclosure.

[0043] The aluminum-containing material can be for example chosen from aluminum-containing ores (such as aluminosillicate minerals, clays, argillite, nepheline, mudstone, beryl, cryolite, garnet, spine!, bauxite, kaolin or mixtures thereof can be used). The aluminum-containing material can also be a recycled industrial aluminum-containing material such as slag, red mud or fly ashes.

[0044] The expression "red mud" as used herein refers, for example, to an industrial waste product generated during the production of alumina. For example, such a waste product can comprise silica, aluminum, iron, calcium, and optionally titanium.
It can also comprise an array of minor constituents such as Na, K, Cr, V, Ni, Ba, Cu, Mn, Pb, AMENDED SHEET

and/or Zn etc. For example, red mud can comprises about 15 to about 80 c1/0 by weight of Fe2O3, about 1 to about 35 % by weight A1203, about 1 to about 65 % by weight of Si02, about 1 to about 20 % by weight of Na20, about 1 to about 20 % by weight of CaO, and from 0 to about 35 % by weight of 1102. According to another example, red mud can comprise about 30 to about 65 % by weight of Fe203, about 10 to about 20 %
by weight A1203, about 3 to about 50 `)/0 by weight of Si02, about 2 to about 10 % by weight of Na2O, about 2 to about 8 `)/0 by weight of CaO, and from 0 to about 25 % by weight of h02.

[0045] The expression "fly ashes" as used herein refers, for example, to an industrial waste product generated in combustion. For example, such a waste product can contain various elements such as silica, oxygen, aluminum, iron, calcium. For example, fly ashes can comprise silicon dioxide (S102) and aluminium oxide (A1203). For example, fly ashes can further comprises calcium oxide (Ca0) and/or iron oxide (Fe203). For example fly ashes can comprise fine particles that rise with flue gases. For example, fly ashes can be produced during combustion of coal. For example, fly ashes can also comprise at least one element chosen from arsenic, beryllium, boron, cadmium, chromium, chromium VI, cobalt, lead, manganese, mercury, molybdenum, selenium, strontium, thallium, and/or vanadium. For example, fly ashes can also comprise rare earth elements and rare metals. For example, fly ashes can be considered as an aluminum-containing material.

[0046] The expression "slag" as used herein refers, for example, to an industrial waste product comprising aluminum oxide and optionally other oxides such as oxides of calcium, magnesium, iron, and/or silicon.

[0047] The expression "rare earth element" (also described as "REE") as used herein refers, for example, to a rare element chosen from scandium, yttrium, lanthanum, cerium, praseodymium, neodymium, promethium, samarium, europium, gadolinium, terbium, dysprosium, holmium, erbium, thulium, ytterbium, and lutetium. The expression "rare metals" as used herein refers, for example, to rare metals chosen from indium, zirconium, lithium, and gallium. These rare earth elements and rare metals can be in various form such as the elemental form (or metallic form), under the form of chlorides, oxides, hydroxides etc. The expression "rare earths" as used in the present disclosure as a synomym of "rare earth elements" that is described above.

[0048] The expression "at least one iron chloride" as used herein refers to FeCl2, FeCl3 or a mixture thereof.

[0049] The term "hematite" as used herein refers, for example, to a compound comprising a,-Fe2O3, 'y-Fe2O3, 13-Fe0.0H or mixtures thereof.

[0050] The expression "iron ions" as used herein refers, for example to ions comprising to at least one type of iron ion chosen from all possible forms of Fe ions. For example, the at least one type of iron ion can be Fe2+, Fe3+, or a mixture thereof.

[0051] The expression "aluminum ions" as used herein refers, for example to ions comprising to at least one type of aluminum ion chosen from all possible forms of Al ions. For example, the at least one type of aluminum ion can be Al3+.

[0052] The expression "at least one aluminum ion", as used herein refers, for example, to at least one type of aluminum ion chosen from all possible forms of Al ions.
For example, the at least one aluminum ion can be Al3+.

[0053] The expression "at least one iron ion'', as used herein refers, for example, to at least one type of iron ion chosen from all possible forms of Fe ions. For example, the at least one iron ion can be Fe2+, Fe3+, or a mixture thereof.

[0054] The expression "at least one precipitated iron ion", as used herein refers, for example, to at least one type of iron ion chosen from all possible forms of Fe ions that was precipitated in a solid form. For example, the at least one iron ion present in such a precipitate can be Fe2+, Fe3+, or a mixture thereof.

[0055] Terms of degree such as "about" and "approximately" as used herein mean a reasonable amount of deviation of the modified term such that the end result is not significantly changed. These terms of degree should be construed as including a deviation of at least 5% or at least 10% of the modified term if this deviation would not negate the meaning of the word it modifies.

[0056] For example, the aluminum-containing material can be leached with HCI
having a concentration of about 10 to about 50 weight %, about 15 to about 45 weight `)/0, of about 18 to about 45 weight % of about 18 to about 32 weight %, of about 20 to about 45 weight /0, of about 25 to about 45 weight /0, of about 26 to about 42 weight %, of about 28 to about 40 weight %, of about 30 to about 38 weight %, or between 25 and 36 weight %.

[0057] For example, the aluminum-containing material can be leached at a temperature of about 125 to about 225 C, about 150 to about 200 C, about 160 to about 190 C, about 185 to about 190 C, about 160 to about 180 C, about 160 to about 175 C, or about 165 to about 170 C.

[0058] For example, the aluminum-containing material can be leached at a pressure of about 4 to about 10 barg, about 4 to about 8 barg, or about 5 to about 6 barg.

[0059] .. For example, the acid can be chosen from HCI, H2SO4, HNO3, H3PO4, and mixtures thereof.

[0060] For example, the processes can further comprise recycling the gaseous HCI
so-produced by contacting it with water so as to obtain a composition having a concentration of about 18 to about 45 weight % or 25 to about 45 weight %.

[0061] For example, the processes can further comprise recycling the gaseous HCI
so-produced by contacting it with water so as to obtain a composition having a concentration of about 18 to about 45 weight `)/0 or about 25 to about 45 weight % and using the composition for leaching the aluminum-containing material.

[0062] For example, the liquid can comprise iron chloride. Iron chloride can comprise at least one of FeCl2, FeCl3, and a mixture thereof.

[0063] For example, the liquid can have an iron chloride concentration of at least 30% by weight; and can then be hydrolyzed at a temperature of about 155 to about 350 C.

[0064] For example, the liquid can be concentrated to a concentrated liquid having an iron chloride concentration of at least 30% by weight; and then the iron chloride can be hydrolyzed at a temperature of about 155 to about 350 C while maintaining a ferric chloride concentration at a level of at least 65% by weight, to generate a composition comprising a liquid and precipitated hematite, and recovering the hematite.

[0065] For example, non-hydrolysable elements with hematite can be concentrated back to a concentration of about 0.125 to about 52 % wt. in circulation loop in view of selective extraction.

[0066] For example, the liquid can be concentrated to a concentrated liquid having a concentration of the at least one iron chloride of at least 30% by weight; and then hydrolyzed at a temperature of about 155 to about 350 C.

[0067] .. For example, the liquid can be concentrated to a concentrated liquid having a concentration of the at least one iron chloride of at least 30% by weight; and then the at least one iron chloride is hydrolyzed at a temperature of about 155 to about while maintaining a ferric chloride concentration at a level of at least 65%
by weight, to generate a composition comprising a liquid and precipitated hematite, and recovering the hematite.

[0068] For example, the liquid can be concentrated to a concentrated liquid having a concentration of the at least one iron chloride of at least 30% by weight; and then the at least one iron chloride is hydrolyzed at a temperature of about 155 to about while maintaining a ferric chloride concentration at a level of at least 65%
by weight, to generate a composition comprising a liquid and precipitated hematite;
recovering the hematite; and recovering rare earth elements and/or rare metals from the liquid.

[0069] For example, the at least one iron chloride can be hydrolyzed at a temperature of about, 150 to about 175, 155 to about 170 or 165 to about 170 C.

[0070] For example, the liquid can comprise magnesium ions and the liquid is reacted with HCI in order to precipitate MgCl2.

[0071] For example, the liquid can comprise magnesium ions and the liquid is reacted with HCI by sparging the liquid with HCI in order to precipitate MgCl2.

[0072] .. For example, the liquid can be concentrated to a concentrated liquid having an iron chloride concentration of at least 30% by weight; and then the iron chloride can be hydrolyzed at a temperature of about 155 to about 350 C while maintaining a ferric chloride concentration at a level of at least 65% by weight, to generate a composition comprising a liquid and precipitated hematite; recovering the hematite; and recovering rare earth elements and/or rare metals from the liquid.

[0073] For example, the processes can further comprise, after recovery of the rare earth elements and/or rare metals, reacting the liquid with HCI so as to cause precipitation of MgC12, and recovering same.

[0074] For example, the processes can further comprise calcining MgC12 into MgO.

[0075] For example, the processes can further comprises, after recovery of the rare earth elements and/or rare metals, reacting the liquid with HCI, and substantially selectively precipitating Na2SO4. For example, Na2SO4 can be precipitated by reacting the liquid with H2S0.4.

[0076] For example, the processes can further comprises, after recovery of the rare earth elements and/or rare metals, reacting the liquid with HCI, and substantially selectively precipitating K2SO4. For example,K2SO4 can be precipitated by adding H2SO4,

[0077] For example, the liquid can be concentrated to a concentrated liquid having an iron chloride concentration of at least 30% by weight; and then the iron chloride can be hydrolyzed at a temperature of about 155 to about 350 C while maintaining a ferric chloride concentration at a level of at least 65% by weight, to generate a composition comprising a liquid and precipitated hematite; recovering the hematite; and reacting the liquid with HCI.For example, such processes can further comprises reacting the liquid with H2SO4 so as to substantially selectively precipitate Na2SO4. The processes can also comprise further reacting the liquid with H2SO4 so as to substantially selectively precipitating K2SO4.

[0078] For example, the processes can comprise reacting dry individual salts (for example Na or K salts) obtained during the processes with H2SO4 and recovering HCI
while producing marketable K2SO4 and Na2SO4 and recovering hydrochloric acid of about 15 to about 90% wt.

[0079] For example, sodium chloride produced in the processes can undergo a chemical reaction with sulfuric acid so as to obtain sodium sulfate and regenerate hydrochloric acid. Potassium chloride can undergo a chemical reaction with sulfuric acid so as to obtain potassium sulfate and regenerate hydrochloric acid. Sodium and potassium chloride brine solution can alternatively be the feed material to adapted small chlor-alkali electrolysis cells. In this latter case, common bases (NaOH and KOH) and bleach (Na0C1 and KOCI) are produced.

[0080] For example, the processes can further comprise, after recovery of the rare earth elements and/or rare metals, recovering NaCI from the liquid, reacting the NaCI
with H2SO4, and substantially selectively precipitating Na2SO4.

[0081] For example, the processes can further comprise, downstream of recovery of the rare earth elements and/or rare metals, recovering KCI from the liquid, reacting the KCI with H2SO4, and substantially selectively precipitating K2SO4.

[0082] For example, the processes can further comprise, downstream of recovery of the rare earth elements and/or rare metals, recovering NaCI from the liquid, carrying out an electrolysis to generate NaOH and Na0C1.

[0083] For example, the processes can further comprise, downstream of recovery of the rare earth elements and/or rare metals, recovering KCI from the liquid, reacting the KCI, carrying out an electrolysis to generate KOH and KQCI.

[0084] For example, the liquid can be concentrated to a concentrated liquid having a concentration of the at least one iron chloride of at least 30% by weight; and then the at least one iron chloride is hydrolyzed at a temperature of about 155 to about while maintaining a ferric chloride concentration at a level of at least 65%
by weight, to generate a composition comprising a liquid and precipitated hematite;
recovering the hematite; and extracting NaCl and/or KCI from the liquid.

[0085] For example, the processes can further comprise reacting the NaCl with H2SO4 so as to substantially selectively precipitate Na2SO4.

[0086] For example, the processes can further comprise reacting the KCI
with H2SO4 so as to substantially selectively precipitate K2SO4. =

[0087] For example, the processes can further comprise carrying out an electrolysis of the NaCI to generate NaOH and Na0C1.

[0088] For example, the processes can further comprise carrying out an electrolysis of the KCI to generate KOH and KOCI.

[0089] For example, the processes can comprise separating the solid from the leachate and washing the solid so as to obtain silica having a purity of at least 95 %, at least 96%, at least 97%, at least 98%, at least 99%, at least 99.5 % or at least 99.9%.

[0090] For example, the processes can comprise reacting the leachate with gaseous HCI so as to obtain the liquid and the precipitate comprising the aluminum ions in the form of AlC13.6H20.

[0091] For example, the processes can comprise reacting the leachate with dry gaseous HCI so as to obtain the liquid and the precipitate comprising the aluminum ions in the form of AlC13.6H20.

[0092] For example, the processes can comprise reacting the leachate with acid of at least 30% wt. that was recovered, regenerated and/or purified as indicated in the present disclosure so as to obtain the liquid and the precipitate comprising the aluminum ions in the form of A1C13.6H20.

[0093]

[0094] For example, the processes can comprise reacting the leachate with gaseous HCI so as to obtain the liquid and the precipitate comprising the aluminum ions, the precipitate being formed by crystallization of AlC13.6H20.

[0095] For example, the processes can comprise reacting the leachate with dry gaseous HCl so as to obtain the liquid and the precipitate comprising the aluminum ions, the precipitate being formed by crystallization of AlC13.6H20.

[0096] For example, the gaseous HCI can have a HCI concentration of at least 85 %
wt. or at least 90 % wt.

[0097] For example, the gaseous HCI can have a HCI concentration of about 90 %
wt. or about 90 % to about 95 % wt..

[0098] For example, during the crystallization of AlC13.6H20, the liquid can be maintained at a concentration of HCI of about 25 to about 35 A) by weight or about 30 to about 32 % by weight.

[0099] For example, the crystallization can be carried out at a temperature of about 45 to about 65 C or about 50 to about 60 C.

[00100] For example, the HCI can be obtained from the gaseous HCl so-produced.

[00101] For example, in the processes of the present disclosure, a given batch or quantity of the aluminum-containing material will be leached, will then be converted into AlC13 and when the HCI generated during calcination of AlC13 into Al2O3 will be used for example to leach another given batch or quantity of the aluminum-containing material.

[00102] For example, the precipitate can be reacted with the base so as to convert A1C13 into Al(OH)3.

[00103] For example, the precipitate can be reacted with the base so as to convert AlC13 into Al(OH)3 and then the precipitate is heated under conditions effective for converting Al(OH)3 into Al2O3.

[00104] For example, the precipitate can be reacted with the base so as to convert AlC13 into Al(OH)3 and then the Al(OH)3 is heated in the presence of steam and under conditions effective for converting the Al(OH)3 into A1203.

[00105] For example, the precipitate, before being reacted with the base, can be recrystallized.

[00106] For example, the precipitate, before being reacted with the base, can be recrystallized after being solubilized in a solvent.

[00107] For example, the solvent can be a polar solvent such as water.

[00108] For example, the precipitate, before being reacted with the base, can be purified by means of a crystallization thereby obtaining A1C13.6H20 and a liquor.

[00109] For example, the precipitate, before being reacted with the base, can be recrystallized, thereby obtaining A1C13=6H20 and a liquor, and separating the crystallized precipitate from the liquor, and wherein the crystallized precipitate is treated with the base in order to convert A1013.6H20 into Al(OH)3.

[00110] For example, the process can comprise:
leaching the aluminum-containing material, that is an industrial waste product chosen from red mud, fly ashes and a mixture thereof, with HCI so as to obtain the leachate comprising aluminum ions and the solid, and separating the solid from the leachate;
reacting the leachate with HCI so as to obtain the liquid and the precipitate comprising the aluminum ions in the form of AlC13, and separating the precipitate from the liquid;
crystallizing or recrystallizing the precipitate so as to obtain a purified precipitate and a liquor;
reacting the purified precipitate with a base; and heating the purified precipitate under conditions effective for converting the purified precipitate into A1203.

[00111] For example, the process can comprise:
leaching the aluminum-containing material, that is an industrial waste product chosen from red mud, fly ashes and a mixture thereof, with HCI so as to obtain the leachate comprising aluminum ions and the solid, and separating the solid from the leachate;

reacting the leachate with HCI so as to obtain the liquid and the precipitate comprising the aluminum ions in the form of AlC13=6H20, and separating the precipitate from the liquid;
purifying the AlC13.6H20 by means of at least one crystallization and/or at least one ion exchange resin, thereby obtaining purified AlC13.6H20 and a liquor;
reacting the purified A1C13.6H20 with a base in order to convert the purified A1013.6H20 into Al(OH)3; and heating the Al(OH)3 under conditions effective for converting Al(OH)3 into A1203.

[00112] For example, the process can comprise:
leaching the aluminum-containing material, that is an industrial waste product chosen from red mud, fly ashes and a mixture thereof, with HCI so as to obtain the leachate comprising aluminum ions and the solid, and separating the solid from the leachate;
reacting the leachate with HCI so as to obtain the liquid and the precipitate comprising the aluminum ions in the form of A1C13=6H20, and separating the precipitate from the liquid;
purifying the A1C13=6H20 by means of at least one crystallization and/or at least one ion exchange resin, thereby obtaining purified AlC13.6H20 and a liquor;
reacting the purified AlC13.6H20 with a base in order to convert the purified AlC13.6H20 into Al(OH)3; and heating the Al(OH)3 in the presence of steam and under conditions effective for converting Al(OH)3 into A1203.

[00113] For example, the process can comprise:

leaching the aluminum-containing material, that is an industrial waste product chosen from red mud, fly ashes and a mixture thereof, with HCl so as to obtain the leachate comprising aluminum ions and the solid, and separating the solid from the leachate;
reacting the leachate with HCl so as to obtain the liquid and the precipitate comprising the aluminum ions in the form of AlC13=6H20, and separating the precipitate from the liquid;
purifying the AlC13.6H20 by means of at least one crystallization and/or at least one ion exchange resin, thereby obtaining purified A1C13.6H20 and a liquor;
reacting the purified A1C13.6H20 with a base in order to convert the purified AlC13.6H20 into Al(OH)3;
purifying the Al(OH)3 by means of at least one crystallization and/or at least one ion exchange resin; and heating the purified Al(OH)3 in the presence of steam and under conditions effective for converting Al(OH)3 into Al2O3.

[00114] For example, the purifying of the A1C13.6H20 can be carried out by means of at least one crystallization or at least two crystallizations.

[00115] For example, the purifying of the Al(OH)3 can be carried out by means Of at least one crystallization or at least two crystallizations.

[00116] For example, the liquor can further be treated with another base, thereby converting AlC13 contained therein into Al(OH)3.

[00117] For example, the liquor can further be treated with another base, thereby converting AlC13 contained therein into Al(OH)3 and reacting the so-obtained Al(OH)3 with the A1C13.6H20 before the purification thereof.

[00118] For example, the base used for reacting with the precipitate can be, for example, NH4OH, KOH, NaOH or mixtures thereof.

[00119] For example, the base used for reacting with the AlC13=6H20 can be, for example NH4OH, KOH, NaOH or mixtures thereof.

[00120] For example, converting AlC13=6H20 into Al2O3 can be carried out in the presence of steam.

[00121] For example, the processes can comprise heating the precipitate at a temperature of at least 850, 900, 925, 930, 1000, 1100, 1200 or 1250 C for converting AlC13 or Al(OH)3 into A1203.

[00122] For example, converting AlC13 into A1203 can comprise calcination of AlC13.

[00123] For example, calcination is effective for converting AlC13 into beta-A1203.

[00124] For example, calcination is effective for converting AlC13 into alpha-A1203.

[00125] For example, converting AlC13 into A1203 can comprise carrying out a calcination via a two-stage circulating fluid bed reactor.

[00126] For example, converting AlC13 into A1203 can comprise carrying out a calcination via a two-stage circulating fluid bed reactor that comprises a preheating system.

[00127] For example, converting AlC13 into Al2O3 can comprise carrying out a calcination at low temperature, for example, about 300 to about 600 C, about 325 to about 550 C, about 350 to about 500 C, about 375 to about 450 C, about 375 to about 425 C, or about 385 to about 400 C and/or injecting steam.

[00128] For example, converting AlC13 into Al2O3 can comprise carrying out a calcination at low temperature, for example, at least 350 C and/or injecting steam.

[00129] For example, converting AlC13 into A1203 can comprise carrying out a calcination at low temperature, for example, less than 600 C and/or injecting steam.

[00130] For example, converting AlC13 into Al2O3 can comprise carrying out a calcination by using coal as combustion source and by using a degasification unit.

[00131] For example, steam (or water vapor) can be injected at a pressure of about 200 to about 700 psig, about 300 to about 700 psig, about 400 to about 700 psig, about 550 to about 650 psig, about 575 to about 625 psig, or about 590 to about 610 psig.

[00132] For example, steam (or water vapor) can be injected and a plasma torch can be used for carrying fluidization.

[00133] For example, the steam (or water vapor) can be overheated.

July 2015 24-07-2015

[00134] For example, converting A1013 into A1203 can comprise carrying out a calcination by means of carbon monoxide (CO).

[00135] For example, converting AlC13 into A1203 can comprise carrying out a calcination by means of a Refinery Fuel Gas (RFG).

[00136] For example, calcination can be carried out by injecting water vapor or steam and/or by using a combustion source chosen from fossil fuels, carbon monoxide, a Refinery Fuel Gas, coal, or chlorinated gases and/or solvents.

[00137] For example, calcination can be carried out by injecting water vapor or steam and/or by using a combustion source chosen from natural gas or propane.

[00138] For example, calcination can be carried out by providing heat by means of electric heating, gas heating, microwave heating,

[00139] For example, the fluid bed reactor can comprise a metal catalyst chosen from metal chlorides.

[00140] For example, thee fluid bed reactor can comprise a metal catalyst that is FeCl3, FeCl2 or a mixture thereof.

[00141] For example, the fluid bed reactor can comprise a metal catalyst that is FeCl3.

[00142] For example, the preheating system can comprise a plasma torch.

[00143] For example, steam can be used as the fluidization medium heating.
Heating can also be electrical.

[00144] For example, a plasma torch can be used for preheating the calcination reactor.

[00145] For example, a plasma torch can be used for preheating air entering in the calcination reactor.

[00146] For example, a plasma torch can be used for preheating a fluid bed.

[00147] For example, the calcination medium can be substantially neutral in terms of 02 (or oxidation). For example, the calcination medium can favorize reduction (for example a concentration of CO of about 100 ppm).

[00148] For example, the calcination medium is effective for preventing formation of C12.

AMENDED SHEET

[00149] For example, the processes can comprise converting Ale! 46=H 0 into ¨2 _Al2O3 by carrying out a calcination of AlC13.6H20 that is provided by the combustion of gas mixture that comprises:
Cl-I4: 0 to about 1% vol;
C2H6 : 0 to about 2% vol;
C3H8 : 0 to about 2% vol;
C4H10 : 0 to about 1% vol;
N2: 0 to about 0.5% vol;
H2: about 0.25 to about 15.1 % vol;
CO: about 70 to about 82.5 % vol; and CO2: about 1.0 to about 3.5% vol.

[00150] Such a mixture can be efficient for reduction in off gas volume of 15.3 to 16.3%; therefore the capacity increases of 15.3 to 16.3% proven on practical operation of the circulating fluid bed. Thus for a same flow it represents an Opex of 0.65'1 6.3% =
10.6%.

[00151] For example, the air to natural gas ratio of (Nm3/h over Nm3/h) in the fluid bed can be about 9.5 to about 10

[00152] For example, the air to CO gas ratio of (Nm3/h over Nm3/h) in the fluid bed can be about 2 to about 3.

[00153] For example, the processes can comprise, before leaching the aluminum-containing material, a pre-leaching removal of fluorine optionally contained in the aluminum-containing material.

[00154] For example, the processes can comprise leaching of the aluminum-containing material with HCI so as to obtain the leachate comprising aluminum ions and the solid, separating the solid from the leachate; and further treating the solid so as to separate SiO2 from TiO2 that are contained therein.

[00155] For example, the processes can comprise leaching the aluminum-containing material with HCI so as to obtain the leachate comprising aluminum ions and the solid, separating the solid from the leachate; and further treating the solid with HCI so as to separate SiO2 from TiO2 that are contained therein.

[00156] For example, the processes can comprise leaching the aluminum-containing material with HCI so as to obtain the leachate comprising aluminum ions and the solid, separating the solid from the leachate; and further treating the solid with HCI at a concentration of less than 20 % wt., at a temperature of less than 85 C, in the presence of MgCl, so as to separate SiO2 from TiO2 that are contained therein.

[00157] For example, converting AlC13 into Al2O3 can comprise carrying out a one-step calcination.

[00158] For example, calcination can be carried out at different temperatures with steam. Temperature applied of superheated steam can be of about 350 C to about 550 C or about 350 C to about 940 C or about 350 C to about 1200 C.

[00159] For example, multi stage evaporation step of the hydrolyser can be carried out to reduce drastically energy consumption.

[00160] For example, the processes can be effective for providing an Al2O3 recovery yield of at least 93 %, at least 94 %, at least 95 `)/0, about 90 to about 95 %, about 92 to about 95 %, or about 93 to about 95 %.

[00161] For example, the processes can be effective for providing a Fe2O3 recovery yield of at least 98 %, at least 99 %, about 98 to about 99.5 %, or about 98.5 to about 99.5 %.

[00162] For example, the processes can be effective for providing a MgO
recovery yield of at least 96 %, at least 97 %, at least 98 %, or about 96 to about 98 %.

[00163] For example, the processes can be effective for providing a HCI
recovery yield of at least 98 %, at least 99 %, or about 98 to about 99.9 %.

[00164] For example, the processes can be effective for providing chlorides of rare earth elements (REE-CI) and chlorides of rare metals (RIV1-C1) in recovery yields of about 75 % to about 96.5 % by using internal processes via an internal concentration loop.

[00165] For example, the processes can be effective for providing hydrochloric acid recovery yield of about 99.75 % with non-hydrolysable elements.

[00166] For example, the aluminum-containing material can be argillite.

[00167] For example, the aluminum-containing material can be bauxite.

[00168] For example, the aluminum-containing material can be red mud.

[00169] For example, the aluminum-containing material can be fly ashes.

[00170] For example, the aluminum-containing material can be chosen from industrial refractory materials.

[00171] For example, the aluminum-containing material chosen from aluminosilicate minerals.

[00172] For example, the processes can be effective for avoiding producing red mud.

[00173] For example, the alumina and the other products are substantially free of red mud.

[00174] For example, HCI can be recycled. For example, such a recycled HCI can be concentrated and/or purified.

[00175] For example, gaseous HCI can be concentrated and/or purified by means of H2SO4. For example, gaseous HCI can be passed through a packed column where it is contacted with a H2SO4 countercurrent flow. For example, by doing so, concentration of HCI can be increased by at least 50 % wt., at least 60 % wt., at least 70 %
wt., at least 75 % wt., at least 80 % wt., about 50 % wt. to about 80 % wt., about 55 % wt.
to about 75 % wt., or about 60 % wt. For example, the column can be packed with a polymer = such as polypropylene(PP) or polytrimethylene terephthalate (PTT).

[00176] For example, gaseous HCl can be concentrated and/or purified by means of CaCl2. For example, gaseous HCI can be passed through a column packed with CaCl2.

[00177] For example, the precipitate can be reacted with a base (for example KOH or NaOH). For example, A1C13 can be converted into Al(OH)3 before calcination.

[00178] For example, the calcination can be carried out by converting Al(OH)3 into A1203.

[00179] For example, the precipitate can reacted with the base so as to convert AlC13 into Al(OH)3.

[00180] For example, the precipitate can be reacted with the base so as to convert AlC13 into Al(OH)3 and then the precipitate can be heated under conditions effective for converting Al(OH)3 into Al2O3.

[00181] For example, the precipitate can be reacted with the base so as to convert AlC13 into Al(OH)3 and then Al(OH)3 can be heated under conditions effective for converting the Al(OH)3 into Al2O3.

[00182] For example, the obtained alumina can be transition alumina, SGA
(smelter grade alumina), HPA (high purity alumina), fused alumina, transition alumina, tabular alumina, calcined alumina, ultra-pure alumina or specialty alumina.

[00183] For example, the processes of the present disclosure can be useful for preparing transition alumina, SGA, HPA, fused alumina, transition alumina, tabular alumina, calcined alumina, ultra-pure alumina or specialty alumina.

[00184] For example, the processes can further comprise converting alumina (A1203) into aluminum. Conversion of alumina into aluminum can be carried out, for example, by using the Hall¨Heroult process. References is made to such a well known process in various patents and patent applications such as US 20100065435; US
20020056650;
US 5,876,584; US 6,565,733. Conversion can also be carried out by means of other methods such as those described in US 7,867,373; US 4,265,716; US 6,565,733 (converting alumina into aluminum sulfide followed by the conversion of aluminum sulfide into aluminum.). For example, aluminium can be produced by using a reduction environment and carbon at temperature below 200 C. Aluminum can also be produced by reduction using potassium and anhydrous aluminum chloride ( Wohler Process).

[00185] According to one example as shown in Fig. 1, the processes can involve the following steps (the reference numbers in Fig. 1 correspond to the following steps) :
1- The aluminum-containing material is reduced to an average particle size of about 50 to about 80 pm.
2- The reduced and classified material is treated with hydrochloric acid which allows for dissolving, under a predetermined temperature and pressure, the aluminum with other elements like iron, magnesium and other metals including rare earth elements and/or rare metals. The silica and titanium (if present in raw material) remain totally undissolved.
3- The mother liquor from the leaching step then undergoes a separation, a cleaning stage in order to separate the purified silica from the metal chloride in solution.

4- The spent acid (leachate) obtained from step 1 is then brought up in concentration with dry and highly concentrated gaseous hydrogen chloride by sparging this one into a crystallizer. This results into the crystallization of aluminum chloride hexahydrate (precipitate) with a minimum of other impurities. Depending on the concentration of iron chloride at this stage, further crystallization step(s) can be required. The precipitate is then separated from the liquid.
5- The aluminum chloride hexahydrate is then calcined (for example by means of a rotary kiln, fluid bed, etc) at high temperature in order to obtain the alumina form. Highly concentrated gaseous hydrogen chloride is then recovered and excess is brought in aqueous form to the highest concentration possible so as to be used (recycled) in the acid leaching step.
6- Iron chloride (the liquid obtained from step 4) is then pre-concentrated and hydrolyzed at low temperature in view of the Fe2O3 (hematite form) extraction and acid recovery from its hydrolysis. All heat recovery from the calcination step (step 5), the leaching part exothermic reaction (step 1) and other section of the processes is being recovered into the pre-concentrator.
10- After the removal of hematite, a solution rich in rare earth elements and/or rare metals can be processed. As it can be seen in Fig.3, an internal recirculation can be done (after the removal of hematite) and the solution rich in rare earth elements and/or rare metals can be used for crystallization stage 4. Extraction of the rare earth elements and/or rare metals can be done as described in W02012/126092 and/or W02012/149642.
Other non-hydrolysable metal chlorides (Me-CI) such as MgCl2 and others then undergo the following steps:
7- The solution rich in magnesium chloride and other non-hydrolysable products at low temperature is then brought up in concentration with dry and highly concentrated gaseous hydrogen chloride by sparging it into a crystallizer.
This results into the precipitation of magnesium chloride as an hexahydrate, for example after sodium and potassium chloride removal.

Date Recue/Date Received 2021-04-01 8- Magnesium chloride hexahydrate is then calcined (either through a rotary kiln, fluid bed, etc.) and hydrochloric acid at very high concentration is thus regenerated and brought back to the leaching step.
9- Other Me-CI undergo a standard pyrohydrolysis step where mixed oxides (Me-0) can be produced and hydrochloric acid at the azeotropic point (20.2%
wt.) is regenerated.

[00186] NaCI can undergo chemical reaction with H2SO4 to produce Na2SO4 and HCI
at a concentration at or above azeotropic concentration. Moreover, KCI can undergo chemical reaction with H2SO4 to produce K2SO4 and HCl having a concentration that is above the azeotropic concentration. Sodium and potassium chloride brine solution can be the feed material to adapted small chlor-alkali electrolysis cells. In this latter case, common bases (NaOH and KOH) and bleach (Na0C1 and KOCI) are produced as well as HCI.

[00187] For example, the liquid can be concentrated to a concentrated liquid having an iron chloride concentration of at least 30% by weight; and then the iron chloride can be hydrolyzed at a temperature of about 155 to about 350 C while maintaining a ferric chloride concentration at a level of at least 65% by weight, to generate a composition comprising a liquid and precipitated hematite, and recovering the hematite.

[00188] For example, the liquid can be concentrated to a concentrated liquid having an iron chloride concentration of at least 30% by weight; and then the iron chloride can be hydrolyzed at a temperature of about 155 to about 350 C while maintaining a ferric chloride concentration at a level of at least 65% by weight, to generate a composition comprising a liquid and precipitated hematite; recovering the hematite; and recovering rare earth elements and/or rare metals from the liquid. For example, the process can further comprise, after recovery of the rare earth elements and/or rare metals, reacting the liquid with HCI so as to cause precipitation of MgCl2, and recovering same.

[00189] As previously indicated, various aluminum-containing materials can be used as starting material of the processes disclosed in the present disclosure.
Examples with clays and bauxite have been carried out. However, the person skilled in the art will understand that the continuous processes can handle high percentages of silica (>55%) and impurities as well as relatively low percentages of aluminum (for example as low as about 15%) and still being economically and technically viable. Satisfactory yields can be obtained (>93-95%) on Al2O3 and greater than 75% on rare earth elements and/or rare metals. No pre-thermal treatment in most cases are required. The processes disclosed in the present disclosure involve special techniques on leaching and acid recovery at very high strength, thereby offering several advantages over alkaline processes.

[00190] In step 1 the mineral, whether or not thermally treated is crushed, milled, dried and classified to have an average particle size of about 50 to about 80 pm.

[00191] In step 2, the milled raw material is introduced into the reactor and will undergo the leaching phase.

[00192] The leaching hydrochloric acid used in step 2 can be a recycled or regenerated acid from steps 5, 6, 8, 9, 10 and 11 (see Fig. 3) its concentration can vary from 15% to 45% weight. percent. Higher concentration can be obtained using membrane separation, cryogenic and/or high pressure approach. The acid leaching can be carried out under pressure and at temperature close to its boiling point thus, allowing a minimal digestion time and extended reaction extent (90%-100%).
Leaching (step 2) can be accomplished in a semi-continuous mode where spent acid with residual free hydrochloric acid is replaced by highly concentrated acid at a certain stage of the reaction or allowing a reduced acid/mineral ratio, thereby reducing reaction time and improving reaction kinetics. For example, kinetic constant k can be: 0.5 ¨
0.75 g/mole.L

[00193] As previously indicated, alkali metals, iron, magnesium, sodium, calcium, potassium, rare earth elements and other elements will also be in a chloride form at different stages. Silica will remain undissolved and will undergo (step 3) a liquid/solid separation and cleaning stage. The processes of the present disclosure tend to recover maximum amount of free hydrochloric acid left and chlorides in solution in order to maximize hydrochloric acid recovery yield, using techniques such as rake classifying, filtration with band filters, centrifugation, and others. Pure SiO2 (one additional leaching stage) cleaning with nano water purity 99% min. Mother liquor free of silica is then named as spent acid (various metal chlorides and water) and goes to the crystallization step (step 4).

[00194] In step 4, the spent acid (or leachate) with a substantial amount of aluminum chloride is then saturated with dry and highly concentrated gaseous hydrogen chloride obtained or recycled from step 5 or with aqueous HCI > 30% wt., which results in the precipitate of aluminum chloride hexahydrate (AIC13 = 6H20). The precipitate retained is then washed and filtered or centrifuged before being fed to the calcination stage (step 5). The remaining of the spent acid from step 4 is then processed to acid recovery system (steps 6 to 8) where pure secondary products will be obtained.

[00195] In step 5, aluminum oxide (alumina) is directly obtained from high temperature conditions. The highly concentrated hydrogen chloride in gaseous form obtained can be fed to steps 4 and 7 for crystallization where it can be treated through hydrophobic membranes. The excess hydrogen chloride is absorbed and used as regenerated acid to the leaching step 2 as highly concentrated acid, higher than the concentration at the azeotropic point (>20.2%). For example, such a concentration can be about 18 to about 45 weight %, about 25 to about 45 weight % or between 25 and 36 weight %.

[00196] After step 4, various chlorides derivatives (mainly iron with magnesium and rare earth elements and rare metals) are next subjected to an iron extraction step. Such a step can be carried out for example by using the technology disclosed in WO
2009/153321.

[00197] In step 6, a hydrolysis at low temperature (155-350 C) is carried out and pure Fe2O3 (hematite) is being produced and hydrochloric acid of at least 15%
concentration is being regenerated. The method as described in WO 2009/153321 is processing the solution of ferrous chloride and ferric chloride, possible mixtures thereof, and free hydrochloric acid through a series of steps pre-concentration step, oxidation step where ferrous chloride is oxidized into ferric form, and finally through an hydrolysis step into an operational unit called hydrolyser where the ferric chloride concentration is maintained at 65 weight % to generate a rich gas stream where concentration ensures a hydrogen chloride concentration of 15-20.2% and a pure hematite that will undergo a physical separation step. Latent heat of condensation is recovered to the pre-concentration and used as the heating input with excess heat from the calcination stage (step 5).

[00198] The mother liquor from the hydrolyser (step 6) can be recirculated partially to first step crystallization process where an increase in concentration of non-hydrolysable elements is observed. After iron removal, the liquor is rich in other non-hydrolysable elements and mainly comprises magnesium chloride or possible mixture of other elements (various chlorides) and rare earth elements and rare metals.

[00199] Rare earth elements and rare metals in form of chlorides are highly concentrated in percentage into the hydrolyser operational unit (step 6) and are extracted from the mother liquor (step 10) where various known techniques can be employed to extract a series of individual RE-0 (rare earth elements and rare metals Date Recue/Date Received 2021-04-01 oxides). Among others, the processes of the present disclosure allows to concentrate to high concentration the following elements, within the hydrolyser: scandium (Sc), galium (Ga), yttrium (Y), dysperosium (Dy), cerium (Ce), praseodynium (Pr), neodynium (Nd), europium (Eu), lanthanum (La), samarium (Sm), gadolinium, (Gd), erbium (Er), zirconium (Zr) and mixtures of thereof. Technologies that can be used for extracting rare earth elements and/or rare metals can be found, for example, in Zhou et al. in RARE
METALS, Vol. 27, No. 3, 2008, p223-227, and in US 2004/0042945. The person skilled in the art will also understand that various other processes normally used for extracting rare earth elements and/or rare metals from the Bayer process can also be used. For example, various solvent extraction techniques can be used. For certain elements, a technique involving octylphenyl acid phosphate (OPAP) and toluene can be used.
HCI
can be used as a stripping agent. This can be effective for recovering Ce203, 5c203, Er203 etc. For example, different sequence using oxalic acid and metallic iron for ferric chloride separation can be used.

[00200] The spent acid liquor from steps 6 and 10 rich in value added metals, mainly magnesium, is processed to step 7. The solution is saturated with dry and highly concentrated gaseous hydrogen chloride from step 5, which results in the precipitation of magnesium chloride hexahydrate. For example, same can be accomplished with HCI
in aqueous form over 30% wt. The precipitate retained, is fed to a calcination stage step 8 where pure MgO (>98% wt.) is obtained and highly concentrated hydrochloric acid (for example of at least 38 %) is regenerated and diverted to the leaching step (step 2). An alternative route for step 7 is using dry gaseous hydrochloric acid from step 8.

[00201] In step 9, metal chlorides unconverted are processed to a pyrohydrolysis step (700-900 C) to generate mixed oxides and where hydrochloric acid from 15-20.2%
wt.
concentration can be recovered.

[00202] According to another example as shown in Fig. 3, the processes can be similar to the example shown in Fig, 1 but can comprise some variants as below discussed.

[00203] In fact, as shown in Fig. 3, the processes can comprise (after step 6 or just before step 10) an internal recirculation back to the crystallization step 4.
In such a case, The mother liquor from the hydrolyser (step 6) can be recirculated fully or partially Date Recue/Date Received 2021-04-01 to the crystallization of step 4 where a concentration increase will occur with respect to the non-hydrolysable elements including rare earth elements and/or rare metals.

[00204] Such a step can be useful for significantly increasing the concentration of rare earth elements and/or rare metals, thereby facilitating their extraction in step 10.

[00205] With respect to step 7, the solution rich in magnesium chloride and other non-hydrolysable products at low temperature is, as previously discussed, then brought up in concentration with dry and highly concentrated gaseous hydrogen chloride by sparging it into a crystallizer. This can result into the precipitation of magnesium chloride as an hexahydrate (for example after sodium and potassium chloride removal).
This can also be accomplished with HCI in aqueous form.

[00206] As shown in Fig. 3, an extra step 11 can be added. Sodium chloride can undergo a chemical reaction with sulfuric acid so as to obtain sodium sulfate and regenerate hydrochloric acid at a concentration at or above the azeotropic point.
Potassium chloride can undergo a chemical reaction with sulfuric acid so as to obtain potassium sulfate and regenerate hydrochloric acid at a concentration above the azeotropic concentration. Sodium and potassium chloride brine solution can be the feed material to adapted small chlor-alkali electrolysis cells. In this latter case, common bases (NaOH and KOH) and bleach (Na0C1 and KOC1) are produced and can be reused to some extent in other areas of the processes of the present disclosure (scrubber, etc.).

[00207] The following are non-limitative examples.
Example 1 Preparation of alumina and various other products

[00208] As a starting material a sample of clay was obtained from the Grande Vallee area in Quebec, Canada.

[00209] These results represent an average of BO tests carried out from samples of about 900 kg each.

[00210] Crude clay in the freshly mined state after grinding and classification had the following composition:
A1203 : 15c/o - 26%;
S102 : 45% - 50%;

Fe2O3: 8% - 9%;
MgO: 1% ¨ 2%;
Rare earth elements and/or rare metals: 0.04% - 0.07%;
LOI : 5% - 10%.

[00211] This material is thereafter leached in a two-stage procedure at 140-with 18-32 weight % HCI. The HCI solution was used in a stoichiometric excess of 10-20% based on the stoichiometric quantity required for the removal of the acid leachable constituents of the clay. In the first leaching stage of the semi-continuous operation (step 2), the clay was contacted for 2.5 hours with required amount or certain proportion of the total amount of hydrochloric acid. After removal of the spent acid, the clay was contacted again with a minimum 18 weight % hydrochloric acid solution for about 1.5 hour at same temperature and pressure.

[00212] A typical extraction curve obtained for both iron and aluminum for a single stage leaching is shown in Fig. 2.

[00213] The leachate was filtered and the solid was washed with water and analyzed using conventional analysis techniques (see step 3 of Fig. 1). Purity of obtained silica was of 95.4% and it was free of any chlorides and of HCl.

[00214] After the leaching and silica removal, the concentration of the various metal chlorides was:
AlC13 : 15-20%;
FeCl2 : 4-6%;
FeCl3 : 0.5-2.0%;
MgCl2: 0.5-2.0 %;
Free HCl: 5-50 g/I

[00215] Spent acid was then crystallized using about 90 to about 98% pure dry hydrochloric acid in gas phase in two stages with less than 25 ppm iron in the aluminum chloride hexahydrate formed. The concentration of HCI in solution (aqueous phase) was about 22 to about 32% or 25 to about 32 % The recovered crystallized material (hydrate form of AlC13 having a minimum purity of 99.8 %) was then calcined at 930 C or 1250 C, thus obtaining the a-portion of the alumina.

[00216] HCI concentration in gas phase exiting the calcination stage was having a concentration greater than 30% and was used (recycled) for crystallization of the A1C13 and MgCl2. Excess of hydrochloric acid is absorbed at the required and targeted concentration for the leaching steps.

[00217] Iron chloride (about 90-95% in ferric form) is then sent to a hydrothermal process in view of its extraction as pure hematite (Fe2O3). This can be done by using the technology described in WO 2009/153321 of low temperature hydrolysis with full heat recovery from calcining, pyrohydrolysis and leaching stage.

[00218] Rare earth elements and rare metals are extracted from the mother liquor of the hydrolyzer where silica, aluminum, iron and a great portion of water have been removed and following preconcentration from hydrolyser to crystallization. It was observed that rare earth elements can be concentrated by a factor of about 4.0 to 10.0 on average within the hydrolyzer itself on a single pass through it i.e.
without concentration loop. The following concentration factors have been noted within the hydrolyzer (single pass):
Ce > 6 La > 9 Nd > 7 Y > 9

[00219] Remaining magnesium chloride is sparged with dry and highly concentrated hydrochloric acid and then calcinated to MgO while recovering high concentration acid (for example up to 38.4%).

[00220] Mixed oxides (Me-0) containing other non-hydrolysable components were then undergoing a pyrohydrolysis reaction at 700-800 C and recovered acid (15-20.2%
wt.) was rerouted for example to the leaching system.
Overall yields obtained:
A1203: 93-95% recovery;
Fe2O3 : 98-99.5% recovery;

Rare earth elements and/or rare metals : 75-93% minimum recovery;
MgO : 96-98% recovery;
Material discarded : 0-5% maximum;
HCI global recovery: 99.75% minimum;
HCl strength as feed to leaching 18-32%;
Red mud production : None.
Example 2 Preparation of alumina and various other products

[00221] A similar feed material (bauxite instead of clay) was processed as per in example 1 up to the leaching stage and revealed to be easily leachable under the conditions established in example 1. It provided an extraction percentage of 100% for the iron and over 90-95% for aluminum. The technology was found to be economically viable and no harmful by-products (red mud) were generated. Samples tested had various concentrations of A1203 (up to 51%), Fe2O3 (up to 27%) and MgO (up to 1.5%).
Example 3 HCI gas enrichment and purification: H2SO4 route

[00222] H2SO4 can be used for carrying out purification of HCI. It can be carried out by using a packing column with H2SO4 flowing counter currently (see Fig. 4). This allows for converting the recovered HCI into HCI having a concentration above the azeotropic point (20.1% wt) and increase its concentration by about 60 to about 70% at minimum.

[00223] Water is absorbed by H2SO4 and then H2SO4 regeneration is applied where H2SO4 is brought back to a concentration of about 95 to about 98% wt. Water release at this stage free of sulphur is recycled back and used for crystallization dissolution, etc.
Packing of the column can comprise polypropylene or polytrimethylene terephthalate (PTT).

[00224] Combustion energy can be performed with off gas preheating air and oxygen enrichment. Oxygen enrichment: +2% represents flame temperature increase by:

maximum.

Example 4 HCI gas enrichment and purification: calcium chloride to calcium chloride hexahydrate (absorption / desorption process)

[00225] As shown in Fig. 5, CaCl2 can be used for drying HCI. In fact, CaCl2 can be used for absorbing water contained into HCI. In such a case, CaCl2 is converted into its hexachloride form (CaCl2 = H20) and one saturated system is eventually switched into regeneration mode where hot air recovered from calcination off gas of alumina and magnesium oxide spray roasting is introduced to regenerate the fixed bed. Such an ion / exchange type process can be seen in Fig. 4 and the cycle can be inversed to switch from one column to another one.

[00226] The person skilled in the art would understand that the processes described in examples 3 and 4 can be used in various different manners. For example, these processes can be combined with the various processes presented in the present disclosure. For example, such purifications techniques can be integrated to the processes shown in Figs. 1, 3 or 6. For example, these techniques can be used downstream of at least one of step chosen from steps 5, 6, 8, 9, 10 and 11 (see Figs. 1 and 3). They can also be used downstream of step 4 and/or step 7. They can also be used downstream of at least one of step chosen from steps 104 to 111 (see Fig.
6).
Example 5 Preparation of alumina and various other products

[00227] This example was carried out by using a process as represented in Figs. 6 and 7. It should be noted that the processes represented in Figs. 6 and 7 differ only by the fact that Fig. 7 show to additional stages i.e. stages 112 and 113.
Raw material preparation

[00228] Raw material, clay for example, was processed in a secondary crusher in the clay preparation plant 101. Dry milling and classifying occurs on a dry basis in vertical roller mills (for example Fuller-Loesche LM 30.41). The clay preparation 101 included three roller mills; two running at a capacity of approximately 160-180 tph and one on standby. Raw material, if required, can be reduced to 85% less than 63 microns.
Processed material was then stored in homogenization silos before being fed to the acid leaching plant 102. Below in Table 1 are shown results obtained during stage 101. If the ore contains the fluorine element, a special treatment can be applied before carrying out the 102 stage. In presence of hydrochloric acid, fluorine can produce hydrofluoric acid.
This acid is extremely corrosive and damaging for human health. Thus, before leaching 102, an optional treatment fluorine separation 112 can be done. Stage 112 can comprise treating the processed material coming from stage 101 with an acid in a pre-leaching treatment so as to remove hydrofluoric acid. Therefore, depending on the composition of the raw material, a fluorine separation stage 112 (or pre-leaching stage 112) can be carried out.
Table 1.
Clay preparation Rate 290 tph SiO2: 50.9%
A1203: 24.0%
Fe2O3: 8.51%
CaO: 0.48%
Composition feed MgO: 1.33%
(main constituents) Na2O: 1.06%
K2O: 2.86%
MnO: 0.16%
Cr2O3: 0.01%
TiO2: 0.85%
P205: 0.145%
Sr0: 0.015%
BaO: 0.05%
V205 0.0321%
Other (including H20 and 9.63%
REE):
Obtained particle size 85% < 63 pm Residual moisture 0.5-0.7%
Yield 99.5% min Acid Leaching

[00229] Next, acid leaching 102 was performed semi-continuously in an 80 m3 glass-lined reactor. Semi-continuous mode comprises replacing reacted acid 1/3 in the reaction period with higher concentration regenerated acid, which greatly improves reaction kinetics. The reactor arrangement comprises for example, a series of three reactors.

[00230] Leaching was performed at high temperature and pressure (about 160 to about 195 C and pressures of about 5 to about 8 barg) for a fixed period of time.
Reaction time was a function of the reaction extent targeted (98% for Al2O3), leaching mode, acid strength, and temperature/pressure applied.

[00231] Spent acid recovered out of the acid leaching 102 was then filtered 103 from unreacted silica and titanium dioxide and washed through an automated filter press where all free HCI and chloride are recovered. This allows, for example, a maximum quantity of about 30 ppm SiO2 going into spent liquor. Cleaned silica at a concentration of =196 % + SiO2 is then produced. Various options are possible at that point.
For example, the 96% silica can undergo final neutralization through caustic bath, cleaning, and then bricketing before storage. According to another example, the silica purified by adding another leaching step followed by a solid separation step that ensures TiO2 removal (see stage 113 in Fig. 7). In that specific case, high purity silica 99.5%+ is produced. In stage 113, titanium and silicium can be separated from one another in various manners. For example, the solid obtained from stage 103 can be leached in the presence of MgCl2 at a temperature below 90 or 80 C and at low acid concentration.
For example, acid concentration can be below 25 or 20 %. The acid can be HCI
or H2SO4. In such a case, titanium remains soluble after such a leaching while titanium is still in a solid form. These solid and liquid obtained after stage 113 are thus separated to provide eventually TiO2 and SiO2. Water input and flow for silica cleaning is in a ratio of 1:1 (silica/water) (150 t/h SiO2 / 150 t/h H20), but comprises of wash water circulation in closed loop in the process and limited amount of process water for final cleaning of the silica and recovery of all chlorides and free HCI generated at the leaching stage. Below in Table 2 are shown results obtained during stage 102.
Table 2.
Acid Leaching Equivalent solid feed rate 259.6 tph Operation mode Semi-continuous Acid Leaching 3.10 @ 23% wt Acid to clay ratio (Equivalent to 3.35 with semi-continuous at 18.0 wt) Regenerated acid 18.0-32.0%
concentration 150-155 C (Pilot) Operating temperature 165-200 C ( Plant) MAWP 120 psig Fe2O3 + 6 HCl 2 FeCl3 + 3H20 Al2O3 + 6 HCI 2 AlC13 + 3 H20 Typical chemical MgO +2 HCl MgCl2 + H20 reactions K2O +2 HCl 2 KCl + H20 Re203 + 6 HCI 2 ReCI3 + 3H20 Spent acid flow to 600-1100 m3/h crystallization FeCl3 4.33%
FeCl2 0.19%
Practical chemical A1C13 16.6%
composition after step MgCl2 0.82%
102 without solid (SiO2) NaCl 1.1%
KCl 1.2%
CaCl2 0.26%
Iron 100%
Extraction yields A1203 98% ___________________ 3i02 Recovery 99.997%
Activation energy only and self-sustained Energy consumption exothermic reaction from 130 C
Heat is recovered and sent to 10%
AlC13 Crystallization

[00232] Spent acid, with an aluminum chloride content of about 20 to about 30 %, was then processed in the crystallization stage 104. Dry and highly concentrated HCI (>90%

wt.) in gas phase was sparged in a two-stage crystallization reactor, which allows the crystallization of aluminum chloride hexahydrate.

[00233] The flow rate of acid through these reactors is about 600 to about 675 m3/h and the reactor was maintained at about 50 to about 60 C during this highly exothermic reaction. Heat was recovered and exchanged to the acid purification 107 part of the plant thus ensuring proper heat transfer and minimizing heat consumption of the plant.
Aluminum chloride solubility decreases rapidly, compared to other elements, with the increase in concentration of free HCI in the crystallization reactor. The concentration of AlC13 for precipitation/crystallization was about 30%

[00234] The HCI concentration during crystallization was thus about 30 to about 32 %
wt.

[00235] The aqueous solution from the crystallization stage 104 was then submitted to the hydrothermal acid recovery plant 105, while the crystals are processed through the decomposition/calcination stage in the calcination plant 106.

[00236] A one-step crystallization stage or a multi-step crystallization stage can be done. For example, a two-steps crystallization stage can be carried out.

[00237] Below in Tables 3A and 3B are shown results obtained during stage 104.
Table 3A.
Aluminum chloride crystallization Number of crystallization steps Operating temperature 50-60 C
Sparging HCI concentration 90% (gaseous) AlC13 = 6H20 (s) Typical chemicals formed Metal chlorides (aq) _________________________ AlC13 = 6H20 residual <5% (practical); 8%

Table 3B.
Typical crystals composition main constituents obtained at pilot scale and feeding calcination Component Weight distribution (/o) A1013 = 6H20 99.978 BaCl2 = 2H20 0.0000 CaCl2 = 6H20 0.0009 CrC14 0.0022 CuCl2 = 2H20 ________________________ 0.0000 FeCl3 = 6H20 0.0019 __ t ¨
KCI 0.0063 MgC12 = 6H20 0.0093 MnCl2 = 4H20 0.0011 NaCI 0.0021 SiCI4 ________________ 0.0004 SrCl2 6H20 I 0.0000 _____________ TiCI4 0.0001 VCI4 _________________ 0.0000 Free CI- 0.0000 Calcination and hydrothermal acid recovery

[00238] The calcination 106 comprises the use of a two-stage circulating fluid bed (CFB) with preheating systems. The preheating system can comprise a plasma torch to heat up steam to process. It processes crystals in the decomposition/calcination stage.
The majority of the hydrochloric acid was released in the first stage which was operated at a temperature of about 350 C, while the second stage performs the calcination itself.
Acid from both stages (about 66 to about 68% of the ,recovered acid from the processes) was then recovered and sent to either to the acid leaching 102 or to the acid purification 107. In the second reactor, which was operated at a temperature of about 930 C, acid was recovered through the condensation and absorption into two columns using mainly wash water from the acid leaching sector 102. Latent heat from this sector was recovered at the same time as large amounts of water, which limits net water input.

[00239] In the iron oxides productions and acid recovery 105 system, which comprises, aqueous solution from the crystallization 104 first undergoes a pre-concentration stage followed by processing in the hydrolyzer reactor. Here, hematite was produced during low temperature processing (about 165 C). A recirculation loop was then taken from the hydrolyzer and is recirculated to the pre-concentrator, allowing the concentration of REE, Mg, K, and other elements. This recirculation loop, allows rare earth element chlorides and/or rare metal chlorides and various metal chlorides concentration to increase without having these products precipitating with hematite up to a certain extent.

[00240] Depending on acid balance in the plant, recovered acid is sent either directly to the 102 or 107 stage.Table 4 shows results obtained in stage 105.
Table 4.
Hydrothermal acid recovery Flowrate from crystallization to 592 m3/h (design) HARP 600 m3/h (design) Operating hydrolyser temperature Regenerated acid concentration 27.4%
Regenerated acid flowrate 205.2 tph HCI
Hematite total production rate 24 TPH (design) HCI recovery > 99.8%
Reflux (recirculation loop) rate in between hydrolyzer and pre- 56 tph concentrator Rare earth element chlorides and/or rare metal chlorides rate = 12.8 t/h in recirculation loop Hematite quality obtained and/or projected Fe2O3 purity > 99.5%
Hydrolysable chlorides <0.2%
Moisture Max 20% after filtration PSD 25-35 microns Density (bulk) 2-3 kg/I
Typical chemical reaction in stage 105 2FeCI3 + 3H20 Fe2O3 + 6 HCI

[002411 Table 5 shows results obtained in stage 106.
Table 5.
Calcination Plant 106 = Two-stage circulating fluid bed (CFB) with pre-heating system Process characteristics:
= Two-stage hydrochloric acid regeneration Production rate (practical) About 66 tph CFB feed rate 371 tph @ 8% humidity*
*High side since crystals will be at 2-3% moisture.
Typical chemical reaction occurring 2(AIC13 = 6 H20) + Energy A1203 + 6 HCI + 9H20 Typical alumina chemical composition obtained from aluminum chloride hexahydrate crystals being fed to calcination Component Weight distribution (%) Al2O3 99.938 Fe2O3 0.0033 S102 0.0032 Cr2O3 0.0063 V205 0.0077 Na 0.0190 MgO 0.0090 P205 0.0039 0.0053 Ca 0.0020 MnO 0.0002 Free Cr Undetectable Rare earth elements and rare metals extractions [00242] The stream that was taken out of 105 recirculation then was treated for rare earth elements and are metals extraction 108, in which the reduction of the remaining iron back to iron 2 (Fe2+), followed by a series of solvent extraction stages, was performed. The reactants were oxalic acid, NaOH, DEHPA (Di-(2-ethylhexyl)phosphoric acid) and TBP (tri-n-butyl phosphate) organic solution, kerosene, and HCI were used to convert rare earth element chlorides and rare metals chlorides to hydroxides.
Countercurrent organic solvent with stripping of solution using HCI before proceeding to specific calcination from the rare earth elements and rare metals in form of hydroxide and conversion to high purity individual oxides. A ion exchange technique is also capable of achieving same results as polytrimethylen terephtalate (PET) membrane.
[00243] Iron powder from 105, or scrap metal as FeO, can be used at a rate dependent on Fe3+ concentration in the mother liquor. HCI (100% wt) at the rate of 1 tph can be required as the stripped solution in REE Solvent Extraction (SX) separation and re-leaching of rare earth elements and/or rare metals oxalates.
[00244] Water of very high quality, demineralized or nano, at the rate of 100 tph was added to the strip solution and washing of precipitates.
[00245] Oxalic acid as di-hydrate at a rate of 0.2 tph was added and contributes to the rare earth elements and rare metals oxalates precipitation. NaOH or Mg0H at a rate of 0.5 tph can be used as a neutralization agent.
[00246] DEHPA SX organic solution at the rate of 500 g/h was used as active reagent in rare earth elements separation while TBP SX organic solution at the rate of 5 kg/h is used as the active reagent for gallium recovery and yttrium separation.
Finally, a kerosene diluent was used at the rate of approximately 2 kg/h in all SX
section.
Calcination occurs in an electric rotary furnace via indirect heating to convert contents to REE203 (oxides form) and maintain product purity.
[00247] Results of various tests made regarding stage 108 are shown in Table 6.
One line divided in subsections (5) to isolate the following elements using solvent extraction:
= Ga203 = Y203 = Sc203 = Eu203 + Er203 + Dy203 = Ce203 +. Nd203 + Pi203 - - -Equivalent output 166.14 kg/h earths oxides Projected production as per pilot testing results Incoming Final extraction individual Feed (kg/h) (kg/h) Ga203 15.66 11.98 Sc203 9.06 8.11 Y203 22.56 20.22 La203 32.24 25.67 Ce203 61.37 51.82 Pr203 8.08 6.18 Nd203 30.3 27.24 Sm203 5.7 4.51 Eu203 1.06 0.95 Gd203 4.5 4.06 Dy203 3.9 3.55 Er203 2.1 1.86 Total 196.55 166.14 Global yield : 84.53%
[00248] Alternatively, stage 108 can be carried out as described in W02012/126092;
W02012/149642.
[00249] The solution after stages 108 and 109 contained mainly MgC12, NaCI, KCI, CaCl2, FeCl2/FeCl3, and AlC13 (traces), and then undergoes the 111 stage.Na, K, Ca that follows the MgO can be extracted in stage 110 by crystallization in a specific order;
Na first, followed by K, and then Ca. This technique can be employed for example in the Israeli Dead Sea salt processing plant to produce MgO and remove alkali from the raw material.
HCI regeneration [00250] Alkali (Na, K), once crystallized, was sent and processed in the alkali hydrochloric acid regeneration plant 110 for recovering highly concentrated hydrochloric acid (I-ICI). The process chosen for the conversion can generate value-added products [00251] Various options are available to convert NaCI and KCI with intent of recovering HCI. One example can be to contact them with highly concentrated sulfuric acid (H2SO4), which generates sodium sulphate (Na2SO4) and potassium sulfate (K2SO4), respectively, and regenerates HCI at a concentration above 90% wt.
Another example, is the use of a sodium and potassium chloride brine solution as the feed material to adapted small chlor-alkali electrolysis cells. In this latter case, common bases (NaOH and KOH) and bleach (Na0C1 and KOCI) are produced. The electrolysis of both NaCI and KCI brine is done in different cells where the current is adjusted to meet the required chemical reaction. In both cases, it is a two-step process in which the brine is submitted to high current and base (NaOH or KOH) is produced with chlorine (Cl2) and hydrogen (H2). H2 and Cl2 are then submitted to a common flame where highly concentrated acid in gas (100% wt) phase is produced and can be used directly in the crystallization stage 104, or to crystallization stages requiring dry highly concentrated acid.
Magnesium oxide [00252] The reduced flow, which was substantially free of most elements (for example AlC13, FeCl3, REE-CI, NaCI, KCI) and rich in MgCl2, was then submitted to the magnesium oxides plant 111. In the MgO, pyrohydrolysis of MgCl2 and any other leftover impurities were converted into oxide while regenerating acid. The first step was a pre-evaporator/crystallizer stage in which calcium is removed and converted into gypsum (CaSO4=2H20) by a simple chemical reaction with sulfuric acid, for which separation of MgO is required. This increases the capacity of MgO roasting and also energy consumption slightly, while substantially recovering HCI. The next step was the specific pyrohydrolysis of MgO concentrated solution by spray roasting. Two (2) main products were generated; MgO that was further treated and HCI (about 18% wt.), which was either recycled back to the upstream leaching stage 102 or to the hydrochloric acid purification plant (107 The MgO-product derived from the spray roaster can require further washing, purification, and finally calcining depending on the quality targeted. The purification and calcining can comprise a washing-hydration step and standard calcining step.
[00253] The MgO from the spray roaster is highly chemically active and wasdirectly charged into a water tank where it reacts with water to form magnesium hydroxide, which has poor solubility in water. The remaining traces of chlorides, like MgCl2, NaCI, dissolved in water. The Mg(OH)2 suspension, after settling in a thickener, was forwarded to vacuum drum filters, which remove the remaining water. The cleaned Mg(OH)2 is then forwarded into a calcination reactor where it is exposed to high temperatures in a vertical multi-stage furnace. Water from hydration is released and allows the transformation of the Mg(OH)2 to MgO and water. At this point, the magnesium oxide was of high purity (> 99%).
HCI purification [00254] The hydrochloric acid purification stage 107 is effective for purifying HCI
regenerated from different sectors (for example 105, 106, 111) and to increase its purity for crystallization, whereas dry highly concentrated acid (> 90% wt.) can be used as the sparging agent. Stage 107 also allowed for controlling the concentration of the acid going back to stage 102 (about 22 to about 32% wt.) and allows total acid and water balance. Total plant water balance is performed mainly by reusing wash water as absorption medium, as quench agent or as dissolution medium at the crystallization stages [00255] For example, purification can be carried out by means of a membrane distillation process. The membrane distillation process applied here occurs when two aqueous liquids with different temperatures are separated through a hydrophobic membrane. The driving force of the process was supplied by the partial pressure vapour difference caused by the temperature gradient between these solutions. Vapour travels from the warm to the cold side. Without wishing to be bound to such a theory, the separation mechanism was based on the vapour/liquid equilibrium of the HCl/water liquid mixture. Practical application of such a technology has been applied to HCl/water, H2SO4/water systems and also on large commercial scales on aqueous solution of sodium chloride with the purpose of obtaining potable water from seawater and nano water production. Therefore membrane distillation was a separation process based on evaporation through a porous hydrophobic membrane. The process was performed at about 60 C and was effective to recover heat from the 104 and 102 stage with an internal water circulation loop, in order to maintain a constant incoming temperature to the membranes. For example, eight membranes of 300,000 m2 equivalent surface area can be used per membrane to obtain a concentration of HCI well above the azeotropic point (i.e. > 36%) of the 1=-1 750 rn3/h and final 90% concentration is then obtained through pressure distillation (rectification column).
[00256] Purification of HCI by processing thus regenerated acid through hydrophobic membrane and separating water from HCl; therefore increasing HCI concentration up to about 36% (above azeotropic point) and therefore allowing with a single stage of rectification through a pressure stripping column to obtain >90% in gaseous phase, for crystallization stage (sparging); and therefore controlling acid concentration into crystallization stages up to 30-35 *am, [00257] As indicated stage 107 was operated at about 60 C and heat input provided by heat recovery from stages 102 to 110. Rectification column was operated at about 140 C in the reboiler part Net energy requirement was neutral (negative in fact at -3.5 Gj/t A1203) since both systems were in equilibrium and in balance.
[00258] For example, the acid purification can be carried out by using adsorption technology over an activated alumina bed. In continuous mode, at least two adsorption columns are required to achieve either adsorption in one of them and regeneration in the other one. Regeneration can be performed by feeding in counter-current a hot or depressurized gas. This technology will result in a purified gas at 100% wt.
[00260] For example, the acid purification can be made by using calcium chloride as entrainer of water. A lean hydrochloric acid solution is contacted with a strong calcium chloride solution through a column. The water is then removed from the hydrochloric acid solution and 99.9% gaseous HCI comes out of the process. Cooling water and cryogenic coolant is used to condense water traces in the HCI. The weak CaCl2 solution is concentrated by an evaporator that ensures the recuperation of calcium chloride.
Depending on the impurities in the incoming HCI solution feed to the column, some metals can contaminate the calcium chloride concentrated solution. A
precipitation with Ca(OH)2 and a filtration allows the removal of those impurities. The column can operate for example at 0.5 barg. This technology can allow for the recuperation of 98%
of the HCI.
[00260] Table 7 shows the results obtained concerning the process shown in Fig. 6.

c o "
r.) Composition Mg0 Stage 107 TOTAIRODUCED =
Slage 101 Stage 102 Stage 106 Stage 105 Stage 108 MO Yield (%) 'Acid(%) Yield f%) Yield I%) tpy Yield (%) Yield (55) Veld(%) YON) .---..
=
t.) CD Main copthuents v:0 * cr No 99S97% _ ¨ -- ---_ -- 930%
A --- 98.02% 9903% _ _ _ _. ¨ 9S03%
5- 0) (1) FO 100.00% 9155% ¨
¨ 9165%
ET --- -- .._ .....

3 6) MK __ Si.998% -- -- 29256 9164%
... ¨ 9164%
o ta S9.998% .. 9&2855 u) co u) 0- Na _ *3986 - -- --1_- 9176%
o ci) K 20.00X

¨ ¨ ¨
-- 197%
_ --o --I P
* 2 Othe004. 620 --- -- _ ___ _ __ ¨ ¨ 0 ,,, = c .
. -,;-- REMO ... 99.81% _ 92.32% ----- -- $1.67% 84.67% Q., ,-, -, Brfroducts ,--NpOli --- _. -- -- 69556 --- ¨ _ 5 cl ¨ 0 0) L.

n, o Na0C1 _ ¨ _ ---0 KOH _ -- -- --- am. ---- -- -_ õ. .õ .õ
gi 3.
iii 5 o ca Readants = 5 . a) H 04(1 - _ -- -- 19,24 -- -- -- -o 5- -0 Fresh:14C196-UP -- --- ¨ --9135% --- 9975% rn a 2.) c O 0 Total --- 9855% 9503%
256,419 92.64% 99.75% 84.67%
o_ --ID (13 O a =
5 .
Z

Table 8.
Chemical composition of obtained alumina Standard used in Element % Weight*
industry A1203 99.938 98.35 min Fe2O3 0.0033 0.0100 SiO2 0.0032 0.0150 TiO2 0.0003 0.0030 V205 0.0008 0.0020 ZnO 0.0005 0.0030 Cr2O3 0.0003 N/A
MgO 0.0090 N/A
MnO 0.0002 N/A
P205 0.0039 0.0010 Cu 0.0030 N/A
Ca 0.0020 0.0030 Na 0.0190 0.4000 0.0053 0.0150 Li 0.0009 N/A
Ba <0.00001 0.0000 Th <0.000001 0.0000 <0.000001 0.0000 Free C1 Not detectable 0.0000 LOI <1.0000 <1.0000 Table 9.
Physical properties of obtained alumina Standard used in Property Orbite Alumina industry PSD < 20pnn 5-10% N/A
PSD < 45pm 10-12% <10%
PSD > 75pm 50-60% N/A
SSA (m2/g) 60-85 60-80 Att. Index 10-12% <10%
a A1203 2-5% <7-9%
Table 10.
Chemical composition of obtained hematite Element % Weight Fe2O3 >99.5%
Hydrolysable elements <0.2%
Table 11.
Physical properties of obtained hematite*
Property Orbite hematite PSDmean 25-35 pm Density (bulk) 2000-3000 kg/m3 Humidity after filtration < 10%
* Material can be produced as brickets Table 12.
Chemical composition of obtained silica Element % Weight SiO2 > 99.7 A1203 <0.25%
MgO
Fe2O3 = 0.1%
Ca0 z001%
Na2O <0.1%
K20 <0.1%
Note: Product may have unbleached cellulose fiber filter aid. Cellulose wood flour.
Table 13.
Physical properties of obtained silica Property Orbite silica PS Dmean 10-20 pm Specific surface area 34 m2/g Density (bulk) 2000-2500 kg/m' Humidity after filtration <40%
Table 14.
Purity of obtained rare earth element oxides Element Purity (%) Ga203 Sc203 La203 Ce203 Pr203 >99%
Nd203 Sm203 Eu203 Gd203 Dy203 Er203 Physical properties of obtained REE-0/RM-0 Property Orbite REE-0/RM-0 PSDmean 2-30 pm Density 5500-13000 kg/m' LOI <1%
Table 15.
Chemical composition of obtained MgO
Element Typical Specification MgO 99.0+ 98.35min CaO 0.0020 0.83 SiO2 0.0000 0.20 max B203 0.0000 0.02 max A1203 0.0300 0.12 max Fe2O3 0.0160 0.57 max Mn02 <0.14 0.14 max LOI 0.7% <1%
Table 16.
Physical properties of obtained MgO
Property Orbite MgO
PSDmean 10 pm Density N/A
LOI 650 kg/m3 Table 17.
Chemical composition of obtained NaOH
Element % Weight Sodium hydroxide 32%
Water 68%
Table 18.
Physical properties of obtained NaOH
Sodium hydroxide Property (NaOH) Physical state Liquid Vapour pressure 14 mmHg Viscosity > 1 Boiling point 100 C
Melting point 0 C
Specific gravity 1.0 Table 19.
Chemical composition of obtained sodium hypochlorite (bleach) Element % Weight Sodium hypochlorite 12%
Sodium hydroxide <1%
Water > 80%
Table 20.
Physical properties of obtained Na0C1 Sodium hypochlorite Property (Na0C1) Physical state Liquid Vapour pressure 1.6 kPa Viscosity N/A
Boiling point 100 C
Melting point -3 C
Specific gravity 1.2 Table 21.
Chemical composition of obtained potassium hydroxide Element % Weight Potassium hydroxide 32%
Water 68%

Table 22.
Physical properties of obtained potassium hydroxide Property KOH
Physical state Liquid Vapour pressure 17.5 mmHg Viscosity N/A
Boiling point 100 C
Melting point N/A
Specific gravity 1.18 Table 23.
Chemical composition of obtained potassium 1 hypochlorite (KOCI) Element % Weight Potassium hypochlorite 12%
Potassium hydroxide < 1%
Water > 80%
Table 24.
Physical properties of obtained potassium hypochlorite Property KOCI
Physical state Liquid Vapour pressure N/A
Viscosity N/A
Boiling point 103 C
Melting point N/A
Specific gravity > 1.0 Table 25.
Chemical composition of obtained calcium sulphate di hydrate Element % Weight Calcium sulphate 100%
d i hyd rate Table 26.
Physical properties of obtained calcium sulphate di hydrate Property Orbite CaSO4=2H20 Physical state Solid Specific gravity 2.32 [00262] The process shown in Fig. 8 is similar to the process shown in Fig. 1.
The main difference resides in the fact that in the process of Fig. 8 comprises stages 25 and 26 instead of stage 5 of Fig. 1. In fact, in Fig. 8, the process comprises, after crystallization of AlC13, to convert AlC13 into Al(OH)3 before calcining the Al(OH)3 into A1203. For example conversion of AlC13 into Al(OH)3 can be carried out by reacting AlC13 with a base (for example KOH or NaOH). Calcination of Al(OH)3 into A1203 can be carried out at high temperature such as about 800 to about 1200 C or about 1000 to about 1200 C.
[00263] In fact, in the processes and the methods of the present disclosure, calcination of AlC13 can be replaced by calcination of Al(OH)3, as shown in Fig. 8 (see the differences between the processes of Fig. 1 and Fig. 8). For example, stages 25 and 26 can replace stage 5 of various processes and methods such as shown in Fig. 3 or replace stage 106 of Figs. 6 and 7. Of course in such a case, HC1 will not be recovered from the calcination.
[00264] In Fig. 9, it can be seen that calcination is also carried out on Al(OH)3. After, the second filtration in Fig. 9, the remaining liquor can be treated with a base (for example NaOH) in order to convert AlC13 contained therein into Al(OH)3. Then, the so-obtained Al(OH)3 can be added (e.g. seeding) to the metal rich liquor that will eventually be treated with HC1(sparging).

24 July 2015 24-07-2015 [00265] More particularly, it can be seen that several of the stages found in the process of Fig. 9 are identical or similar to some stages found in Figs. 7 and 8. For example, the optional material preparation of stage 201 is similar to stages 101 and 1 of Fig. 7 and 8, respectively. The leaching and filtration stages 202 and 203 of Fig. 9 correspond to stages 102 and 103 of Fig. 7 or to stages 2 and 3 of Fig. 8.
Then, AlC13.6H20 is crystallized by sparging HCI obtained after the filtration carried out in stage 203. In brief, stage 204 of Fig. 9, is similar to stage 104 of Fig, 7 or stage 4 of Fig. 8.
[00266] After obtaining crystallized AlC13.6H20, a filtration stage 219 is carried out in the process of Fig. 9. Then, the so-obtained A1C13.6H20 is eventually dissolved into water 220 and crystallized 221 to further remove impurities. After the filtration 222, carried out in order to recover the recrystallized AlC13-6H20, the so-obtained product (A1C13.6H20) is reacted with a base in order to convert it into Al(OH)3 in stage 225.
Finally, in stage 226, Al(OH)3 is converted into alumina (A1203) by means of a decomposition and/or calcination process. It was found that such a purification sequence that involves three different precipitation and/or crystallization stages (two under the form of A1C13-6H20; and one under the form of Al(OH)3) was really helpful and efficient for obtaining higher purities alumina. It was also found that a purification sequence that involves two different precipitation and/or crystallization stages (one under the form of AlC13-6H20; and one under the form of Al(OH)3) was really helpful and efficient for obtaining higher purities in terms of the final product. Without wishing to be bound to such a theory, it is believed that these combined purification sequences are quite successful since they allow to precipitate the aluminum ions under acidic and basic conditions, thereby allowing for solubilizing impurities that are soluble both acidic and basic media.
[00267] Depending on the composition of the starting material used, the liquid portion obtained after filtration stage 219 can contain various components such as Fe, rare metals (RM), rare earth elements (REE), etc. For example, the rare metals chosen from indium, zirconium, lithium, and gallium. Moreover, for example, the rare earth elements can be chosen from scandium, yttrium, lanthanum, cerium, praseodymium, neodymium, promethium, samarium, europium, gadolinium, terbium, dysprosium, holmium, erbium, thulium, ytterbium, and lutetium.

AMENDED SHEET

[00268] Such liquor can eventually be treated by means of an hydrothermal process in stage 205. Such a stage is similar to stage 105 of Fig. 7 and to stage 6 of Fig. 8. For example, ferric oxide can be obtained from stage 205 and the remaining liquid portion can be treated in stage 208 in order to isolate and/or recover at least one rare metal and/or at least one rare earth element. Various techniques can be used in stage 208. Suitable techniques that can be used are described in W02012/126092;
W02012/149642; and W02013/138900.
[00269] The person skilled in the art would understand that depending on the composition of the starting material, the composition of the liquor obtained after filtration stage 219 will vary. Thus, the products that can be recovered and/or isolated downstream of stage 019 i.e. in stages 205 and 208 will vary accordingly.
[00270] After stage 222, a liquid portion or liquor can eventually comprise uncrystallized A1C13. In such a case, uncrystallized aluminum ions can be recovered from the liquor by contacting the liquor with a base (such as NaOH or KOH) in stage 223. The so-obtained Al(OH)3 can then be combined with the leachate obtained from stages 202 and 203 in order to crystallize A1C13.6H20 in stage 204.
[00271] The dotted lines found in Fig. 9, downstream of stage 205, represent optional stages or reusing and/or recycling HC1 so-produced. For example, HC1 generated during stage 205 can optionally be used in at least one stage chosen from 202, 204, 219 and 222. For example, before being used in at least one of stage chosen from 202, 204, 219 and 222, the HC1 generated in stage 205 can be further concentrated and/or purified. For example, the HC1 can be concentrated and/or purified by a process as shown in Fig. 4 and/or in Fig. 5.
[00272] The person skilled in the art would understand that some adjustments of the parameters can be made in accordance with the selection of the starting material used in the process of Fig. 9. As previously indicated, the aluminum-containing material can be, for example, an industrial waste product. Such a waste product can be, for example, red mud, fly ashes or a mixture thereof.
[00273] The processes of the present disclosure provide a plurality of important advantages and distinction over the known processes.

Date Recue/Date Received 2021-04-01 [00274] The processes of the present disclosure provide fully continuous and economical solutions that can successfully extract alumina from various type of materials while providing ultra pure secondary products of high added value including highly concentrated rare earth elements and rare metals. The technology described in the present disclosure allows for an innovative amount of total acid recovery and also for a ultra high concentration of recovered acid. When combing it to the fact that combined with a semi-continuous leaching approach that favors very high extraction yields and allows a specific method of crystallization of the aluminum chloride and concentration of other value added elements. These processes also allow for preparing aluminum with such a produced alumina.
[00275] Specifically through the type of equipment used (for example vertical roller mill) and its specific operation, raw material grinding, drying and classifying can be applicable to various kinds of material hardness (furnace slag for example), various , types of humidity (up to 30%) and incoming particle sizes. The particle size established provides the advantage, at the leaching stage, of allowing optimal contact between the minerals and the acid and then allowing faster kinetics of reaction. Particles size employed reduces drastically the abrasion issue and allows for the use of a simplified metallurgy/lining when in contact with hydrochloric acid.
[00276] A further advantage of the processes of the present disclosure is the combined high temperature and high incoming hydrochloric acid concentration.
Combined with a semi continuous operation where the free HCl driving force is used systematically, iron and aluminum extraction yields do respectively reach 100%
and 98% in less than about 40 % of the reference time of a basic batch process.
Another advantage of higher HCI concentration than the concentration at azeotropic point is the potential of capacity increase. Again a higher HCl concentration than the concentration of HCI at the azeotropic point and the semi-continuous approach represent a substantial advance in the art.
[00277] Another advantage in that technique used for the mother liquor separation from the silica after the leaching stage countercurrent wash, is that band filters provide ultra pure silica with expected purity exceeding 96%.
[00278] The crystallization of AlC13 into AlC13 = 6H20 using dried, cleaned and highly concentrated gaseous HCI as the sparging agent allows for a pure aluminum chloride hexahydrate with only few parts per million of iron and other impurities. A
minimal number of stages are required to allow proper crystal growth.

[00279] The direct interconnection with the calcination of AlC13 = 6H20 into which does produce very high concentration of gas allows the exact adjustment in continuous of the HCI concentration within the crystallizer and thus proper control of the crystal growth and crystallization process.
[00280] The applicants have now discovered fully integrated and continuous processes with substantially total hydrochloric acid recovery for the extraction of alumina and other value added products from various materials that contain aluminum (clay, bauxite, aluminosilicate materials, slag, red mud, fly ashes etc.) containing aluminum. In fact, the processes allows for the production of substantially pure alumina and other value added products purified such as purified silica, pure hematite, pure other minerals (ex: magnesium oxide) and rare earth elements products. In addition, the processes do not require thermal pre-treatment before the acid leach operation.
Acid leach is carried out using semi-continuous techniques with high pressure and temperature conditions and very high regenerated hydrochloric acid concentration. In addition, the processes do not generate any residues not sellable, thus eliminating harmful residues to environment like in the case of alkaline processes.
[00281] The advantage of the high temperature calcination stage, in addition for allowing to control the a-form of alumina required, is effective for providing a concentration of hydrochloric acid in the aqueous form (>38%) that is higher than the concentration of HCI at the azeotropic point and thus providing a higher incoming HCI
concentration to the leaching stage. The calcination stage hydrochloric acid network can be interconnected to two (2) crystallization systems and by pressure regulation excess HCI can be being absorbed at the highest possible aqueous concentration. The advantage of having a hexahydrate chloride with low moisture content (< 2%) incoming feed allows for a continuous basis to recover acid at a concentration that is higher than the azeotropic concentration. This HCI balance and double usage into three (3) common parts of the processes and above azeotropic point is a substantial advance in the art.
[00282] Another advantage is the use of the incoming chemistry (ferric chloride) to the iron oxide and hydrochloric acid recovery unit where all excess heat load from any calcination part, pyrohydrolysis and leaching part is being recovered to preconcentrate the mother liquor in metal chloride, thus allowing, at very low temperature, the hydrolysis of the ferric chloride in the form of very pure hematite and the acid regeneration at the same concentration than at its azeotropic point.

[00283] A further major advantage of the instant process at the ferric chloride hydrolysis step is the possibility to concentrate rare earth elements in form of chlorides at very high concentration within the hydrolyser reactor through an internal loop between hydrolyzer and crystallization. The advantage in that the processes of the present disclosure benefit from the various steps where gradual concentration ratios are applied. Thus, at this stage, in addition to an internal concentration loop, having the silica, the aluminum, the iron and having in equilibrium a solution close to saturation (large amount of water evaporated, no presence of free hydrochloric acid) allows for taking rare earth elements and non-hydrolysable elements in parts per million into the incoming feed and to concentrate them in high percentage directly at the hydrolyser after ferric chloride removal Purification of the specific rare elements and rare earths oxides oxides (RE-0) can then be performed using various techniques when in percentage levels. The advantage is doubled here: concentration at very high level of rare earth elements using integrated process stages and most importantly the approach prevents from having the main stream (very diluted) of spent acid after the leaching step with the risk of contaminating the main aluminum chloride stream and thus affecting yields in A1203. Another important improvement of the art is that on top of being fully integrated, selective removal of components allows for the concentration of rare earth elements to relatively high concentration (percentages).
[00284] Another advantage of the process is again a selective crystallization of MgCl2 through the sparging of HCI from either the alumina calcination step or the magnesium oxide direct calcination where in both cases highly concentrated acid both in gaseous phase or in aqueous form are being generated. As per aluminum chloride specific crystallization, the direct interconnection with the calcination reactor, the HCI gas very high concentration (about 85 to about 95 %, about 90 to 95 % or about 90 % by weight) allows for exact adjustment in continuous of the crystallizer based on quality of magnesium oxide targeted. Should this process step (MgO production or other value added metal oxide) be required based on incoming process feed chemistry, the rare earth elements extraction point then be done after this additional step; the advantage being the extra concentration effect applied.
[00285] The pyrohydrolysis allows for the final conversion of any remaining chloride and the production of refined oxides that can be used (in case of clay as starting material) as a fertilizer and allowing the processing of large amount of wash water from the processes with the recovery hydrochloric acid in close loop at the azeotropic point for the leaching step. The advantage of this last step is related to the fact that it does totally close the process loop in terms of acid recovery and the insurance that no residues harmful to the environment are being generated while processing any type of raw material, as previously described.
[00286] A major contribution to the art is that the proposed fully integrated processes of the present disclosure is really allowing, among others, the processing of bauxite in an economic way while generating no red mud or harmful residues. In addition to the fact of being applicable to other natural of raw materials (any suitable aluminum-containing material or aluminous ores), the fact of using hydrochloric acid total recovery and a global concentration that is higher than the concentration at the azeotropic point (for example about 21% to about 38%), the selective extraction of value added secondary products and compliance (while remaining highly competitive on transformation cost) with environmental requirements, represent major advantages in the art.
[00287] It was thus demonstrated that the present disclosure provides fully integrated processes for the preparation of pure aluminum oxide using a hydrochloric acid treatment while producing high purity and high quality products (minerals) and extracting rare earth elements and rare metals.
[00288] With respect to the above-mentioned examples 1 to 5, the person skilled in the art will also understand that depending on the starting material used i.e.
argillite, bauxite, kaolin, nepheline, aluminosilicate materials, red mud, slag, fly ashes, industrial refractory materials etc., some parameters might need to be adjusted consequently. In fact, for example, certain parameters such as reaction time, concentration, temperature may vary in accordance with the reactivity of the selected starting material (aluminum-containing material).
[00289] It was found that by reacting the precipitate with a base, prior to converting it into alumina, the alumina so-obtained offered several advantages over alumina produced by converting AlC13 into A1203. In fact, it was observed that the loose density of the alumina obtained by converting AlC13 into A1203 was about 0.3 to 0.6 g/mL, while the loose density of the alumina obtained by converting Al(OH)3 into A1203 was about 0.6 to 1.2 g/mL. Thus, such a density that is about two times superior offers significant advantages regarding costs related to stocking and transportation. Since the density is about two times superior, it means that the space required to stock the same volume is two times inferior. Moreover, such a higher density also considerably simplifies handling of the alumina and aluminum production process. In fact, a fluffy alumina can cause several handling and process issues.
[00290] The person skilled in the art would understand that all the various embodiments presented in the present disclosure can be combined, when applicable, to any other processes and embodiments thereof presented in the present disclosure.
[00291] While a description was made with particular reference to the specific embodiments, it will be understood that numerous modifications thereto will appear to those skilled in the art. Accordingly, the above description and accompanying drawings should be taken as specific examples and not in a limiting sense.

Claims

WHAT IS CLAIMED IS:

1. A process for preparing alumina, said process comprising:
leaching an aluminum-containing material, that is an industrial waste product chosen from red mud, fly ashes and a mixture thereof, with HCI so as to obtain a leachate comprising aluminum ions and a solid, and separating said solid from said leachate;
reacting said leachate with HCI so as to obtain a liquid and a first precipitate comprising said aluminum ions in the form of A1C13-6H20, said first precipitate being formed by crystallization of AlC13.6H20 and separating said first precipitate from said liquid;
recrystallizing said A1C13.6H20 in order to obtain a second precipitate comprising said A1C13.6H20 and a liquor comprising uncrystallised A1C13, separating said second precipitate from said liquor;
reacting said liquor with a first base to obtain Al(OH)3 and combining said Al(OH)3 with said leachate to obtain said first precipitate; and reacting said second precipitate with a second base and heating said second precipitate under conditions effective for converting said second precipitate into A1203.

2. The process of claim 1, wherein said aluminum-containing material is leached with HCI having a concentration of about 25 to about 45 weight %.

3. The process of claim 1, wherein said aluminum-containing material is leached with HCI having a concentration of about 25 to about 45 weight % at a temperature of about 125 to about 225 C.

4. The process of claim 1, wherein said aluminum-containing material is leached with HCI having a concentration of about 25 to about 45 weight % at a temperature of about 160 to about 190 C.

Date Recue/Date Received 2021-04-01

5. The process of claim 1, wherein said aluminum-containing material is leached with HCI having a concentration of about 25 to about 45 weight % at a temperature of about 160 to about 175 C.

6. The process of claim 1, wherein said aluminum-containing material is leached with HCI having a concentration of about 25 to about 45 weight % at a temperature of about 185 to about 190 C.

7. The process of claim 1, wherein said aluminum-containing material is leached with HCI having a concentration of about 18 to about 45 weight %.

8. The process of claim 1, wherein said aluminum-containing material is leached with HCI having a concentration of about 18 to about 45 weight % at a temperature of about 125 to about 225 C.

9. The process of claim 1, wherein said aluminum-containing material is leached with HCI having a concentration of about 18 to about 45 weight % at a temperature of about 160 to about 190 C.

10. The process of claim 1, wherein said aluminum-containing material is leached with HCI having a concentration of about 18 to about 45 weight % at a temperature of about 160 to about 175 C.

11. The process of claim 1, wherein said aluminum-containing material is leached with HCI having a concentration of about 18 to about 45 weight % at a temperature of about 185 to about 190 C.

12. The process of claim 1, wherein said aluminum-containing material is leached with HCI having a concentration of about 18 to about 32 weight % at a temperature of about 125 to about 225 C.

13. The process of claim 1, wherein said aluminum-containing material is leached with HCI having a concentration of about 18 to about 32 weight % at a temperature of about 160 to about 190 C.

Date Recue/Date Received 2021-04-01

14. The process of claim 1, wherein said aluminum-containing material is leached with HCI having a concentration of about 18 to about 32 weight % at a temperature of about 160 to about 175 C.

15. The process of claim 1, wherein said aluminum-containing material is leached with HCI having a concentration of about 18 to about 32 weight % at a temperature of about 185 to about 190 C.

16. The process of any one of claims 1 to 15, wherein said liquid comprises at least one iron chloride that is FeCl2, FeCI3 or a mixture thereof.

17. The process of claim 16, wherein said liquid is concentrated to a concentrated liquid having a concentration of said at least one iron chloride of at least 30% by weight; and then hydrolyzed at a temperature of about 155 to about 350 C.

18. The process of claim 16, wherein said liquid is concentrated to a concentrated liquid having a concentration of said at least one iron chloride of at least 30% by weight; and then said at least one iron chloride is hydrolyzed at a temperature of about 155 to about 350 C while maintaining a ferric chloride concentration at a level of at least 65% by weight, to generate a composition comprising a further liquid and precipitated hematite, and recovering said hematite.

19. The process of claim 16, wherein said at least one iron chloride is hydrolyzed at a temperature of about 165 to about 170 C.

20. The process of claim 16, wherein said liquid is concentrated to a concentrated liquid having a concentration of said at least one iron chloride of at least 30%
by weight; and then said at least one iron chloride is hydrolyzed at a temperature of about 155 to about 350 C while maintaining a ferric chloride concentration at a level of at least 65% by weight, to generate a composition comprising a further liquid and precipitated hematite; recovering said hematite;
and recovering rare earth elements and/or rare metals from said further liquid.

21. The process of claim 20, wherein said at least one iron chloride is hydrolyzed at a temperature of about 155 to about 170 C.

Date Recue/Date Received 2021-04-01

22. The process of claim 20 or 21, further comprising, after recovery of said rare earth elements and/or said rare metals, reacting said further liquid with HCI
so as to cause precipitation of MgCl2, and recovering the same.

23. The process of claim 22, further comprising calcining MgCl2 into Mg0.

24. The process of claim 22, further comprising calcining MgCl2 into Mg0 and recycling the gaseous HCI so-produced by contacting it with water so as to obtain a composition having a concentration of HCI of about 25 to about 45 weight % and using said composition for leaching said aluminum-containing material.

25. The process of claim 22, further comprising calcining MgCl2 into Mg0 and recycling the gaseous HCI so-produced by contacting it with water so as to obtain a composition having a concentration of HCI of about 18 to about 45 weight % and using said composition for leaching said aluminum-containing material.

26. The process of any one of claims 21 to 25, further comprising, downstream of recovery of said rare earth elements and/or rare metals, recovering NaCI from said further liquid, reacting said NaCI with H2SO4, and selectively precipitating Na2SO4.

27. The process of any one of claims 21 to 26, further comprising, downstream of recovery of said rare earth elements and/or rare metals, recovering KCI from said further liquid, reacting said KCI with H2504, and selectively precipitating K2504.

28. The process of any one of claims 21 to 25, further comprising, downstream of recovery of said rare earth elements and/or rare metals, recovering NaCI from said further liquid, carrying out an electrolysis to generate NaOH and NaOCI.

29. The process of any one of claims 21 to 25 and 28, further comprising, downstream of recovery of said rare earth elements and/or rare metals, recovering KCI from said further liquid, reacting said KCI, carrying out an electrolysis to generate KOH and KOCI.

Date Recue/Date Received 2021-04-01

30. The process of claim 16, wherein said liquid is concentrated to a concentrated liquid having a concentration of said at least one iron chloride of at least 30%
by weight; and then said at least one iron chloride is hydrolyzed at a temperature of about 155 to about 350 C while maintaining a ferric chloride concentration at a level of at least 65% by weight, to generate a composition comprising a further liquid and precipitated hematite; recovering said hematite; and extracting NaCI and/or KCI from said further liquid.

31. The process of claim 30, further comprising reacting said NaCI with H2SO4 so as to selectively precipitate Na2SO4.

32. The process of claim 30, further comprising reacting said KCI with H2504 so as to selectively precipitate K2504.

33. The process of claim 30, further comprising carrying out an electrolysis of said NaCI to generate NaOH and NaOCI.

34. The process of claim 30, further comprising carrying out an electrolysis of aid KCI to generate KOH and KOCI.

35. The process of any one of claims 1 to 15, wherein said liquid comprises magnesium ions and said liquid is reacted with HCI in order to precipitate MgCl2.

36. The process of any one of claims 1 to 15, wherein said liquid comprises magnesium ions and said liquid is reacted with HCI by sparging said liquid with HCI in order to precipitate MgCl2.

37. The process of any one of claims 1 to 36, wherein said process comprises separating said solid from said leachate and washing said solid so as to obtain silica having a purity of at least 95 %.

38. The process of any one of claims 1 to 36, wherein said process comprises separating said solid from said leachate and washing said solid so as to obtain silica having a purity of at least 98 %.

Date Recue/Date Received 2021-04-01

39. The process of any one of claims 1 to 36, wherein said process comprises separating said solid from said leachate and washing said solid so as to obtain silica having a purity of at least 99 %.

40. The process of any one of claims 1 to 39, wherein said process comprises reacting said leachate with gaseous HCI so as to obtain said liquid and said precipitate comprising said aluminum ions, said precipitate being formed by crystallization of A1C13.6H20.

41. The process of any one of claims 1 to 39, wherein said process comprises reacting said leachate with dry gaseous HCI so as to obtain said liquid and said precipitate comprising said aluminum ions, said precipitate being formed by crystallization of A1C13.6H20.

42. The process of claim 40 or 41, wherein said gaseous HCI has a HCI
concentration of at least 85 % by weight.

43. The process of claim 40 or 41, wherein said gaseous HCI has a HCI
concentration of at least 90 % by weight.

44. The process of claim 40 or 41, wherein said gaseous HCI has a HCI
concentration of about 90 % by weight.

45. The process of claim 40 or 41, wherein said gaseous HCI has a concentration of about 90 % to about 95 % by weight.

46. The process of any one of claims 40 to 45, wherein during said crystallization of A1C13.6H20, said liquid is maintained at a concentration of HCI of about 25 to about 35 % by weight.

47. The process of any one of claims 40 to 45, wherein during said crystallization of A1C13.6H20, said liquid is maintained at a concentration of HCI of about 30 to about 32 % by weight.

48. The process of any one of claims 40 to 47, wherein said crystallization is carried out at a temperature of about 45 to about 65 C.

Date Recue/Date Received 2021-04-01

49. The process of any one of claims 40 to 47, wherein said crystallization is carried out at a temperature of about 50 to about 60 C.

50. The process of any one of claims 1 to 49, wherein said process comprises heating said precipitate at a temperature of at least 1200 C for converting Al(OH)3 into A1203.

51. The process of any one of claims 1 to 49, wherein said process comprises heating said precipitate at a temperature of at least 1250 C for converting Al(OH)3 into A1203.

52. The process of any one of claims 1 to 49, wherein said process comprises heating said precipitate at a temperature of at least 900 C for converting Al(OH)3 into A1203.

53. The process of any one of claims 1 to 52, wherein said process comprises converting Al(OH)3 into alpha-A1203.

54. The process of any one of claims 1 to 49, wherein said process comprises heating said precipitate at a temperature of at least 350 C for converting Al(OH)3 into A1203.

55. The process of any one of claims 1 to 49, wherein said process comprises heating said precipitate at a temperature of about 350 C to about 500 C for converting Al(OH)3 into A1203.

56. The process of any one of claims 1 to 49, wherein said process comprises heating said precipitate at a temperature of about 375 C to about 450 C for converting Al(OH)3 into A1203.

57. The process of any one of claims 1 to 49, wherein said process comprises heating said precipitate at a temperature of about 375 C to about 425 C for converting Al(OH)3 into A1203.

Date Recue/Date Received 2021-04-01

58. The process of any one of claims 1 to 49, wherein said process comprises heating said precipitate at a temperature of about 385 C to about 400 C for converting Al(OH)3 into A1203.

59. The process of any one of claims 54 to 58, wherein said process comprises converting Al(OH)3 into beta-A1203.

60. The process of any one of claims 1 to 59, wherein converting Al(OH)3 into is carried out in the presence of steam.

61. The process of any one of claims 1 to 60, wherein converting Al(OH)3 into A1203 comprises carrying out a calcination via a two-stage circulating fluid bed reactor.

62. The process of any one of claims 1 to 60, wherein converting Al(OH)3 into comprises carrying out a calcination via a two-stage circulating fluid bed reactor that comprises a preheating system.

63. The process of claim 62, wherein said preheating system comprises a plasma torch.

64. The process of claim 63, wherein said plasma torch is effective for preheating air entering into the fluid bed reactor.

65. The process of claim 63, wherein said plasma torch is effective for generating steam that is injected into the fluid bed reactor.

66. The process of claim 63, wherein said plasma torch is effective for generating steam that is as fluidization medium in a fluid bed reactor.

67. The process of process of any one of claims 1 to 66, wherein converting Al(OH)3 into A1203 comprises carrying out a one-step calcination.

68. The process of process of any one of claims 1 to 67, wherein said process comprises converting Al(OH)3 into A1203 by carrying out a calcination of Al(OH)3, said calcination comprising steam injection.

Date Recue/Date Received 2021-04-01

69. The process of claim 68, wherein steam is injected at a pressure of about 200 to about 700 psig (about 1.38 to about 4.83 MPa).

70. The process of claim 68, wherein steam is injected at a pressure of about 300 to about 700 psig (about 2.07 to about 4.83 MPa).

71. The process of claim 68, wherein steam is injected at a pressure of about 400 to about 700 psig (about 2.76 to about 4.83 MPa).

72. The process of claim 68, wherein steam is injected at a pressure of about 550 to about 650 psig (about 3.79 to about 4.48 MPa).

73. The process of claim 68, wherein steam is injected at a pressure of about 575 to about 625 psig (about 3.96 to about 4.31 MPa).

74. The process of claim 68, wherein steam is injected at a pressure of about 590 to about 610 psig (about 4.07 to about 4.21 MPa).

75. The process of any one of claims 68 to 74, wherein steam is injected and a plasma torch is used for carrying fluidization.

76. The process of any one of claims 60 and 68 to 75, wherein said steam is overheated.

77. The process of any one of claims 1 to 76, wherein said process comprises converting Al(OH)3 into A1203 by carrying out a calcination of Al(OH)3 that is provided by the combustion of gas mixture that is a an incoming smelter gas or a reducer offgas.

78. The process of any one of claims 1 to 76, wherein said process comprises converting Al(OH)3 into A1203 by carrying out a calcination of Al(OH)3 that is provided by the combustion of gas mixture that comprises :
CH4 : 0 to about 1% vol;
C2H6 : 0 to about 2% vol;
C3H8 : 0 to about 2% vol;

Date Recue/Date Received 2021-04-01 C4H10 : 0 to about 1% vol;
N2 : 0 to about 0.5% vol;
H2 : about 0.25 to about 15.1 % vol;
CO : about 70 to about 82.5 % vol; and CO2 : about 1.0 to about 3.5% vol.

79. The process of claim 79, wherein 02 is absent from said mixture.

80. The process of any one of claims 1 to 76, wherein said process comprises converting Al(OH)3 into A1203 by carrying out a calcination of Al(OH)3 in which is provided by electric heating, gas heating or microwave heating.

81. The process of claim 61, wherein the fluid bed reactor comprises a metal catalyst chosen from metal chlorides.

82. The process of claim 81, wherein the fluid bed reactor comprises FeC13, FeC12 or a mixture thereof.

83. The process of any one of claims 1 to 82, wherein said process is a semi-continuous process.

84. The process of any one of clainis 1 to 82, wherein said process is a continuous process.

85. The process of any one of claims 1 to 84, wherein said process is effective for providing an A1203 recovery yield of at least 93 %.

86. The process of any one of claims 1 to 84, wherein said process is effective for providing an A1203 recovery yield of about 90 % to about 95 %.

87. The process of any one of claims 1 to 86, wherein said process is effective for providing a Fe203 recovery yield of at least 98 %.

Date Recue/Date Received 2021-04-01

88. The process of any one of claims 1 to 86, wherein said process is effective for providing a Fe2O3 recovery yield of about 98 % to about 99.5 %.

89. The process of any one of claims 1 to 88, wherein said process is effective for providing a Mg0 recovery yield of at least 96 %.

90. The process of any one of claims 1 to 88, wherein said process is effective for providing a Mg0 recovery yield of about 96 to about 98 %.

91. The process of any one of claims 1 to 90, wherein said aluminum-containing material is leached at a pressure of about 4 to about 10 barg (about 0.4 to about 1 MPa).

92. The process of any one of claims 1 to 90, wherein said aluminum-containing material is leached at a pressure of about 4 to about 8 barg (about 0.4 to about 0.8 MPa).

93. The process of any one of claims 1 to 90, wherein said aluminum-containing material is leached at a pressure of about 5 to about 6 barg (about 0.5 to about 0.6 MPa).

94. The process of any one of claims 1 to 93, further comprising, before leaching said aluminum-containing material, a pre-leaching removal of fluorine optionally contained in said aluminum-containing material.

95. The process of any one of claims 1 to 94, comprising leaching said aluminum-containing material with HCI so as to obtain said leachate comprising aluminum ions and said solid, separating said solid from said leachate; and further treating said solid so as to separate SiO2 from TiO2 that are contained therein.

96. The process of any one of claims 1 to 94, comprising leaching said aluminum-containing material with HCI so as to obtain said leachate comprising aluminum ions and said solid, separating said solid from said leachate; and further treating said solid with HCI so as to separate SiO2 from TiO2 that are contained therein.

Date Recue/Date Received 2021-04-01

97. The process of any one of claims 1 to 94, comprising leaching said aluminum -containing material with HCI so as to obtain said leachate comprising aluminum ions and said solid, separating said solid from said leachate; and further treating said solid with HCI at a concentration of less than 20 % by weight, at a temperature of less than 85 C, in the presence of MgCl2, so as to separate SiO2 from TiO2 that are contained therein.

98. The process of any one of claims 1 to 97, wherein said aluminum-containing material is red mud.

99. The process of any one of claims 1 to 97, wherein said aluminum-containing material is fly ashes.

100. The process of any one of claims 1 to 97, wherein said aluminum-containing material is a mixture of fly ashes and red mud.

101. The process of any one of claims 1 to 100, wherein said first base is KOH.

102. The process of any one of claims 1 to 100, wherein said first base is NaOH.

103. The process of any one of claims 1 to 100, wherein said first base is NH4OH.

104. The process of any one of claims 1 to 103, wherein said second base is KOH.

105. The process of any one of claims 1 to 103, wherein said second base is NaOH.

106. The process of any one of claims 1 to 103, wherein said second base is NH4OH.

107. The process of any one of claims 1 to 106, wherein said process comprises dissolving said A1C13.6H20 into water and recrystallizing said A1C13.6H20 in order to obtain the second precipitate comprising said A1C13-6H20 and the liquor comprising uncrystallised A1C13, separating said second precipitate from said liquor.

Date Recue/Date Received 2021-04-01

108. A process for preparing aluminum, said process comprising :
obtaining alumina by means of a process as defined in any one of claims 1 to 107; and converting said A1203 into aluminum.

109. The process of claim 108, wherein said conversion of A1203 into aluminum is carried out by means of the Hall-Héroult process.

110. The process of claim 108, wherein said conversion of A1203 into aluminum is carried out by using a reduction environment and carbon at temperature below 200 C.

111. The process of claim 108, wherein said conversion of A1203 into aluminum is carried out by means of the Wohler Process.

112. The process of claim 108, wherein said conversion of A1203 into aluminum is carried out by converting A1203 into A1253 and then converting A1253 into aluminum.

Date Recue/Date Received 2021-04-01