FI128281B

FI128281B - Processing of Industrial Metal-Containing Waste Materials

Info

Publication number: FI128281B
Application number: FI20165972A
Authority: FI
Inventors: Pertti Koukkari; Jussi Rastas; Pekka Saikkonen; Väinö Hintikka
Original assignee: Teknologian Tutkimuskeskus Vtt Oy
Priority date: 2016-12-15
Filing date: 2016-12-15
Publication date: 2020-02-28
Also published as: FI20165972L; EP3555327A4; WO2018109283A1; EP3555327A1

Abstract

The present invention relates to a process for separating metals using a series of precipitations from waste materials of the zinc or steel industry, or both. The method is characterized in carrying out the precipitations using hydroxides or sulfur-containing chemicals selected from sulfates, sulfides, sulfur oxides and sulfites, or both, in order to obtain metal precipitates as well as an aqueous sulfur-containing solution, the latter optionally being recycled in the process, whereafter a final precipitate is carried to a thermal step, for forming.

Description

PROCESSING OF INDUSTRIAL METAL-CONTAINING WASTE MATERIALS

Background of the Invention

Field of the Invention [0001] The present invention concerns the hydrometallurgical processing of industrial waste materials in order to separate fractions containing valuable metals therefrom.

[0002] Particularly, the materials to be processed are obtained from the zinc or steel industries, or both. Suitable waste materials that can be processed according to the invention, either separately or combined, are jarosite and goethite rejects of the zinc industry, as well as the zinc-containing dusts (such as electric arc furnace dusts, i.e. EAF 15 dusts) of the steel industry.

Description of Related Art [0003] Presently, a main part (85 %) of the world’s zinc production takes place by an electrolytic process. After the year 1970, several zinc factories started to operate using so-called jarosite and goethite methods, whereby the recovered yield of zinc in these processes increased from less than 90% to 97-98%. Although the obtained yield of zinc increased, a negative result of these new processes was the resulting large amount of waste, in the form of jarosite and goethite residues.

[0004] Jarosite is a basic hydrous sulfate mineral of iron (AfFesSO^OEQe], A = H3O, Na, K, NH4), which is formed in ore deposits by the oxidation of iron sulfides, and is, as mentioned, produced as a byproduct during the purification and refining of zinc.

[0005] Goethite is a hydroxide mineral of iron (FeOOH), which is found in soil and other low-temperature environments. It exists as an iron ore, which is commonly found in waste materials of the steel industry, but is, as mentioned above, also formed during zinc production.

20165972 prh 15-12-2016 [0006] For these residues, the zinc processes require sufficiently large waste areas close to the factories, and these waste areas need to be fitted with impermeable foundations. Also other environmental requirements need to be considered. In many cases also valuable elements contained by the ore end up in these waste residues.

[0007] Constantly increasing amounts of waste have become a serious issue for zinc producers, and an environmental problem. On the other hand, the valuable elements contained in the waste also constitute a considerable potential value.

[0008] In the electrolytic zinc process, there is thus a considerable need for a procedure for removing or at least considerably reducing the continuously growing waste problem in an economical manner, and simultaneously recovering valuable substances from the waste.

[0009] In US3871859A there is described a process for utilizing jarosite waste by acidifying and crystallizing, but this process fails to separate the different metals contained in the jarosite from each other. Instead, the product is used as a slightly purified combination of components for fertilization purposes.

[0010] About half of the currently produced zinc is used in prevention of corrosion, whereby a major portion will be returned with steel waste into the electromelting-type processes of the steel industry. During this processing, the zinc becomes evaporated and oxidized, and is carried away from the process with the formed dusts.

[0011] The zinc content of these dusts of the steel factories varies between 30 and

40%. The dusts are commonly processed using the Walz process (see e.g. EP0709472B1), which is not a simple process, and which includes the problem that a portion of the halogens added to the process remains in the product, i.e. in the Wälz oxide. The halogens are usually removed from the Wälz oxide using a two- or three-fold wash with a Na2CO3 solution, before the thus treated oxides can be fed to the electrolytic zinc process. It would pose a considerable advantage if the dusts of the steel industry could be processed in a manner facilitating early removal of halogens, taking place in a close vicinity to the zinc manufacturer.

[0012] The research on jarosite waste has to the present date been focusing on the utilization of metallic sulphates, among others, in the construction material industry, while

20165972 prh 15-12-2016 the possibility of using these in combination with enrichment sands in landfills has been determined (see e.g. Moors & Dijkema 2006, Rathore & al. 2014). These utilizations involve a problem, relating to the toxicity of the soluble heavy metals contained in these materials, as well as the sulfur and arsenic.

[0013] However, storing the waste at permanent industrial waste disposal sites requires extraordinary measures for eliminating possible leakage and runoff, as well as other detrimental environmental effects. Thus, this storage alternative would cause high costs and would be difficult to implement.

[0014] While the demand for raw materials increases, an increasing amount of attention is still focused on the recovery of critical metals contained in jarosite waste. The various possibilities linked with the recovery of metallic value from jarosite waste have been emphasized, among others, in the report from the year 2013 by the UN

Environmental Program (UNEP), concerning the recycling of metals. For example in Korea, it has been attempted to develop a high-temperature pyrometallurgical process based on the so-called Ausmelt technique (see the UNEP report), where the roasting of zinc waste, or early reductive melting, is combined with the recovery of metals.

[0015] Applying a high-temperature melting technique to the treatment of jarosite waste is, however, technically challenging and, due to its high demand of energy, uneconomical. Some possibilities relating to early thermal treatments and subsequent hydrometallurgical processing have also been presented in the research, but the suggested techniques have not resulted in commercial solutions.

[0016] In the late 1970’s in Finland, particularly Outokumpu Oy began to pay attention to the processing of jarosite (both the jarosite obtained from the process and the jarosite stored in the waste area. However, the used procedure focused mainly on a sulfidization and flotation in order to separate lead, silver and gold from the material, while 30 other components remained as a waste (US 4,385,038).

Summary of the Invention [0017] It is an object of the present invention to solve at least some of the problems 35 related to the prior art.

20165972 prh 15-12-2016 [0018] Thus, according to a first aspect of the present invention, there is provided a multi step process for separating metals from a waste material of the zinc or steel industry, or combined waste materials.

[0019] According to a second aspect of the present invention, there is provided a use of said process in separating valuable metals, such as zinc, lead, iron, silver and gold, from waste materials of the zinc or steel industry, or combined waste materials.

[0020] The suggested hydrometallurgical processing of the invention makes it possible to eliminate the halogen problem formed in connection with using the Walz process, while in a unique manner providing a procedure for the zinc industry for utilizing the jarosite precipitate, which has up to the present date been stored as hazardous waste, in connection with zinc production. Further, a concentrate containing significant amounts of lead, silver and gold is also obtained in the present process.

[0021] In the present process, several types of industrial waste, including waste dust of the steel mills and jarosite or goethite waste of the zinc mills, can be processed by hydrometallurgy, either separately or combined. The products include the valuable metal fractions that these wastes contain, recovered as utilizable concentrates.

[0022] The invention provides an advantageous and environmentally friendly solution for recycling the zinc-containing waste dust of the steel mills in connection with the recovery of metals from the jarosite precipitate formed as a waste in the zinc mills.

[0023] Using the present invention, it is possible to utilize, in an advantageous and cost-efficient manner, not only the main components of jarosite (i.e. zinc, iron and lead), but also the critical metals it contains in smaller concentrations (such as silver, gold, indium and gallium), and similar metals of other waste materials.

Brief Description of the Drawings [0024] FIGURE lisa block diagram illustrating the processing steps in accordance with at least some embodiments of the present invention.

[0025] FIGURE 2 is an alternative block diagram illustrating the process steps in accordance with at least one embodiment of the present invention.

Embodiments of the Invention

20165972 prh 15-12-2016 [0026] Definitions

The “hydrometallurgical processing” of the invention is intended to cover a multistep procedure for separating at least the valuable components from the starting material, i.e. the waste, the procedure including steps of acidifying, precipitating, concentrating and heat treating, as well as one or more steps of metals recovery.

The term “waste” is intended to cover all by-products of metal production industries, particularly the metal-containing by-products of the zinc and steel industries.

In said context, the term “metal” is intended to encompass the elements of the periodic table of elements that belong to the transition metals, post-transition metals and metalloids, the groups of transition and post-transition metals having the highest significance.

At least one precipitation step of said process is carried out using a “sulfur25 containing chemical”, which is intended to cover sulfates, sulfides, sulfur oxides and sulfites, which generate chemicals that easily can be reacted into a suitable form to be recycled, and optionally used in a sulfur dioxide treatment.

[0027] Thus, the present invention relates to a process for separating metals from waste materials of the zinc or steel industry, or both. The material to be processed can be a metal-containing waste material or a combination of two or more such waste materials.

[0028] The process includes a series of precipitations using e.g. sulfur-containing chemicals selected from sulfates, sulfides, sulfur oxides and sulfites, and hydroxides, in

20165972 prh 15-12-2016 order to obtain an aqueous sulfur-containing solution, which optionally is recycled in the process, whereafter a final precipitate is carried to a thermal step, for forming and separating solid oxides from the sulfates remaining in the solution phase.

[0029] Figure 1 illustrates a process scheme in accordance with an embodiment of the invention.

[0030] According to this embodiment, a sulfuric acid treatment using hot concentrated sulfuric acid is first carried out on an industrial zinc-containing dust, such as 10 an electric arc furnace dust (an EAF dust).

[0031] Preferably, the acid is heated to a temperature of > 100°C, particularly to about 200°C, and is mixed with the preheated (e.g. 100-150°C) dust. The temperature of the formed mixture then rises, typically to more than 250°C. As a result, the oxides in the 15 dust are sulfatized to form a sulfate phase, while the halogenides also contained therein are decomposed and sulfatized, generally at least to a degree of 70%. The water and the halogen hydrides of the formed mixture are transferred to the gas phase, from where they can be removed, e.g. by compressing, preferably using water washing.

[0032] The reactions taking place in this process step include one or more, preferably all, of the following listing:

(1) 2NaCl + H₂SO₄ => Na₂SO₄ + 2HC1 (2) Na₂O + H₂SO₄ => Na₂SO₄ + H₂O (3) 2KF + H₂SO₄ => K₂SO₄ + 2HF (4) K₂O + H₂SO₄ => K₂SO₄ + H₂O (5) MgO + H₂SO₄ => MgSO₄ + H₂O (6) CaF₂ + H₂SO₄ => CaSO₄ + 2HF (7) CaO + H₂SO₄ => CaSO₄ + H₂O (8) A1₂O₃ + 3H₂SO₄ => A1₂(SO₄)₃ + 3H₂O (9) MnO + H₂SO₄ => MnSO₄ + H₂O (10) ZnO + H₂SO₄ => ZnSO₄ + H₂O (11) CuO + H₂SO₄ => CuSO₄ + H₂O (12) NiO + H₂SO₄ => NiSO₄ + H₂O (13) CoO + H₂SO₄ => CoSO₄ + H₂O (14) PbO + H₂SO₄ => PbSO₄ + H₂O (15) Fe₂O₃ + 3H₂SO₄ => Fe₂(SO₄)₃ + H₂O [0033] By continuing the treatment of the sulfatized dust with a heat treatment at a temperature of 400-600°C, the halogens can be removed from the solid fraction. When using temperatures at the higher end of this range, the halogen removal is almost complete 5 (at 600 °C, 98% of the chlorides are removed and 95% of the fluorides). Such dehalogenated sulfatized dusts can be carried as such to be used in zinc processes.

[0034] However, when treated further as herein described, such an almost complete halogen removal is not required.

[0035] The obtained solid sulfatized dust, optionally mixed with further metalcontaining waste materials, such as jarosite and/or goethite waste, are fed to a SO2 dissolution step.

20165972 prh 15-12-2016 [0036] The temperature during said dissolution step is preferably >50°C and <100°C, most suitably about 90°C, whereby one or more of the reactions of the following listing take place, typically all of the reactions, as long as the relevant metals are present in the treated waste material.

(16) 2A[Fe₃(SO4)2(OH)6] (s) + 3 SO2 (aq) => A2SO4 (aq) + 6 FeSCh (aq) + 6 H2O (A = NH4, Na, K) (17) Fe₂(SO4)3 (s) + SO2 aq) + 2 H2O => 2 FeSCh (aq) + 2 H2SO4 (aq) (18) MeFe₂O4 (s) + SO2 (aq) + 2 H2SO4 (aq) => MeSCh (aq) + 2 FeSCh (aq) + 2 H2O (Me = Zn, Cu, Cd) (19) AI2O3 (s) + 3 H2SO4 (aq) => Ah(SO4)₃ (aq) + 3 H2O (20) MgO (s) + H2SO4 (aq) => MgSCh (aq) + H2O (21) MnO (s) + H2SO4 (aq) => MnSCh (aq) + H2O (22) NiO (s) + H2SO4 (aq) => NiSCh (aq) + H2O (23) CoO (s) + H2SO4 (aq) => CoSO4 (aq) + H2O

0 (24) AS2O3 (s) + 3 H2O => 2 H3ASO3 (aq) (25) Sb₂O₃ (s) + H2O => 2 HSbCh (aq) (26) SnO2 (s) + SO2 (aq) => SnSCh (aq) (27) GcCh (s) + SO2 (aq) => GeSCh (aq) (28) ImCh (s) + 3 H2SO4 (aq) => In₂(SO4)₃ (aq) + 3 H2O

5 (29) Ga₂O3 (s) + 3 H2SO4 (aq) => Ga₂(SO4)3 (aq) 3 H2O

20165972 prh 15-12-2016 [0037] During the dissolution, a vast amount of the metal components of the raw material(s) is/are dissolved, thus ending up in the formed SO2 solution phase, and the iron (Fe³⁺) is reduced to its Fe²⁺ form, which has higher potential in the subsequent reactions.

Said reduction also produces sulfuric acid (see e.g. reaction (17)), which causes further dissolution of components of the raw material(s), which require harsh dissolution conditions (e.g. ferrite).

[0038] After the SO2 dissolution step, the formed phases are separated, the obtained 10 solid residue is washed and the washing solution is added to the SO2 solution phase.

[0039] This SO2 solution phase is, according to the embodiment described in Fig. 1, processed further in later described steps, while the solid residue is carried to a sulfidization and flotation step for concentrating and recovering a metals fraction.

[0040] In this sulfidization and flotation, the dissolution residue is first suspended into water to form a slurry. Subsequently, sodium sulfide, or another similar sulfide reagent, is added to the sludge (see reactions (30) and (31)) in an amount equivalent to the lead and silver present in the residue, and the mixture is floated to give a first fraction of metal sulfides and a first SO4 solution.

[0041] In this step, the following reactions take place:

(30) PbSCh (s) + Na2S (aq) => PbS (s) + Na2SC>4 (aq) (31) Ag₂SO4 (s) + Na2S (aq) => Ag2S (s) + Na2SC>4 (aq) [0042] Typical products of this step are concentrates containing lead, silver and gold. The remaining waste materials are preferably discarded as a sulfide waste residue, while the SO4 solution can be recycled or combined with the previously obtained SO2 solution.

[0043] In the flotation, it is assumed that the yield of lead in comparison to the dissolution residue is 97%, and the yield of silver and gold is 95%. No significant amounts

20165972 prh 15-12-2016 of minor components of the dissolution residue, such as gypsum and S1O2, are included in the sulfide residue, although trace amounts are inevitably carried there.

[0044] In the following step shown in Fig. 1, the indium (In) and gallium (Ga), and possibly germanium (Ge) are separated from the SO2 solution (optionally combined with the first SO4 solution) by adjusting the pH to a level of 3.5-4, preferably using a solution containing magnesium hydroxide (Mg(OH)₂) as the pH adjustment agent (causing precipitation). The temperature of the solution is between 80 and 90°C. Other possible pH adjustment agents are zinc oxide (ZnO), Walz-oxide (or the ZnO therein), calcium oxide (CaO), calcium hydroxide (Ca(OH)₂) and calcium carbonate (CaCOs).

[0045] Due to the possibility to use a hydroxide as the pH adjustment agent, this step can be called a hydroxide precipitation step. The fractions obtained in this step are thus a second SO4 solution and a solid phase containing a first residue of metal hydroxides.

[0046] The solubility product values of the obtained hydroxides vary to some extent, depending on their source. If the solubility product values for the indium and gallium hydroxides are equal to or lower than 10(exp(-36)), and if the corresponding value for aluminium hydroxide is 10(exp(-31)), it is possible to obtain a sharp distinction. If the pH 20 adjustment range is 3.5-4, the precipitate will, however, contain also aluminium hydroxide.

[0047] When assuming that indium, gallium and aluminium hydroxides are precipitated in a pure form, and that germanium is precipitated in the form of its hydroxide, the following reactions take place:

(32) In₂(SO4)3 (aq) + 3 Mg(0H)₂ (s) => 2 In(0H)₃ (s) + 3 MgSCh (aq) (33) Ga2(SO4)₃ (aq) + 3 Mg(OH)₂ (s) => 2 Ga(0H)₃ (s) + 3 MgSCh (aq) (34) GeSCh (aq) + Mg(0H)₂ (s) => Ge(OH)₂ (s) + MgSO4 (aq) (34’) Al₂(SO₄)3(aq) + 3Mg(OH)₂(s) => 2A1(OH)₃(s) + 3MgSO₄(aq) (35) H₂SO4 (aq) + Mg(0H)₂ (s) => MgSCh(aq) + 2 H₂O [0048] Preferably, the precipitated hydroxides are separated from the second SO4 solution, and are washed, whereby the washing solution can be added to the original second SO4 solution. The thus recovered precipitate will contain In, Ga, Ge and Al hydroxides.

20165972 prh 15-12-2016 [0049] According to another option, the Indium, Gallium and Germanium can be separated using a liquid-liquid extraction.

[0050] The following step according to Fig. lisa sulfide precipitation, which is carried out by adding hydrogen sulfide (H₂S) to the second SO4 solution obtained in the previous step, while adjusting the pH of the solution, for example using Mg(0H)₂, so that no significant amounts of iron (Fe²⁺) is precipitated. The reactions taking place during this step of the process preferably include the following:

(36) 2 HsAsCh (aq) + 3 H2S (aq) => AS2S3 (s) + 6 H2O (37) 2HSbO₂(aq) + 3 H2S (aq) => Sb₂S₃ (s) + 4 H2O (38) SnSCh (aq) + H2S (aq) => SnS (s) + H2SO4 (aq) (39) CuSCh (aq) + H2S (aq) => CuS (s) + H2SO4 (aq) (40) CdSO4 (aq) + H2S (aq) => CdS (s) + H2SO4 (aq) (41) ZnSCh (aq) + H2S (aq) => ZnS (s) + H2SO4 (aq) (42) H2SO4 (aq) + Mg(0H)₂ (s) => MgSCh (aq) + 2 H2O [0051] Thus, a third SO4 solution is obtained, which can then be carried to the following step shown in Fig. 1, while also a sulfide precipitate is obtained, which contains 20 the sulfides shown in the above reactions.

[0052] This precipitate can then be treated further with a polysulfide solution, preferably an ammonium poly sulfide solution, whereby the sulfides of the precipitate can be separated into a solid phase, containing a third fraction of metal sulfides, and a solution 25 phase. Thus, As₂S₂, Sb₂S₂ and SnS dissolve as in the following reactions, whereas CuS, CdS and ZnS remain in solid form.

(43) AS2S3 (s) + 3 (NH4)₂S (aq) + 2 S => 2 (NH4)₃AsS4 (aq) (44) Sb₂S3 (s) + 3 (NH4)₂S (aq) + 2 S => 2 (NH4)₃SbS4 (aq) (45) SnS (s) + (NH4)₂S (aq) + S => (N^ftSnSs (aq) (Ammoniumpolysulfide: (NHiftSiftn = 2 ... 5)) [0053] The obtained solid and solution phases are then separated, whereby the solid phase is washed using a solution based on ammonium polysulfide, and the washing solution is combined with the solution phase.

20165972 prh 15-12-2016 [0054] The solution phase and the dissolved metals therein are can then be treated by an addition of sulfuric acid, whereby the sulfides of arsenic, antimony and tin are precipitated (reactions (46) - (48)).

(46) 2 (NH4)iAsS4 (aq) + 3 H2SO4 (aq) => AS2S5 (s) + 3 (NH4)₂SO4 (aq) + 3 H2S (aq) (47) 2 (NH4)iSbS4 (aq) + 3 H2SO4 (aq) => Sb₂S₅ (s) + 3 (NH4)₂SO4 (aq) + 3 H2S (aq) (48) (NH4)2SnS3 (aq) + H2SO4 (aq) => SnS2 (s) + (NFU^SCh (aq) + H2S (aq) [0055] After these separations, a sulfide solution remains, which can be recycled and reused.

[0056] The above mentioned third SO4 solution is, according to the procedure shown in Fig. 1, then concentrated by a multiphase evaporation crystallization, where the formed 15 steam phase can optionally be cooled, compressed and returned to the SO2 dissolution step for reuse.

[0057] The salt phase remaining after the evaporation, after removal of the steam phase, is, according to Fig. 1, carried to a thermal step, where the following reactions 20 preferably take place:

(49) (NH4)₂SO4 (s) + O2 (g) => N2 (g) + SO2 (g) + 4 H2O (g) (50) 2 FeSO4 H2O (s) => Fe₂O₃ (s) + 2 SO2 (g) + 1/2 O2 (g) + 2 H2O (g) (51) MgSO4 H2O (s) => MgSO4(s) + H2O (g) (52) MeSO4 H₂O(s) => MeO (s) + SO2 (g) + 1/2 O2 (g) + H2O (g) (Me = Mn, Ni, Co) (53) A12(SO4)₃-6 H2O (s) => AI2O3 (s) + 3 SO2 (g) + 3/2 O2 (g) + 6 H2O (g) [0058] Thus, a remaining portion of the metals form a mixture of solubilized sulfates 30 and non-soluble oxides. In typical conditions, the iron, manganese, nickel, cobalt and aluminum of said salt phase are turned into their oxide forms during said thermal step, whereas magnesium remains as a sulfate.

20165972 prh 15-12-2016 [0059] Due to their SO2 content, the gaseous products also formed are preferably returned to the above described SO2 dissolution step.

[0060] The solid residue obtained in the thermal step is preferably carried to a water 5 washing step, where the soluble components are transferred to the solubilized sulfate phase, and the non-soluble oxide phase (mostly containing Fe2O3) forms an iron concentrate.

[0061] Based on the above, according to a preferred embodiment of the invention, 10 the overall process includes the following steps:

- a sulphuric acid treatment using hot concentrated sulphuric acid, preferably carried out on a waste dust obtained from the steel industry,

- optionally mixing one or more further waste materials with the acid-treated material, preferably including jarosite or goethite, or both, particularly being jarosite,

- a sulphur dioxide (SO2) dissolution step, where a solid residue and a SO2 solution phase are formed,

- sulfidization and flotation of the solid dissolution residue, to obtain a first fraction of metal sulfides and a first SO4 solution, which metal sulfides can be recovered

- hydroxide addition and subsequent precipitation of metal hydroxides from the combined solution phases of the dissolution step (the SO2 solution) and of the sulfidization and flotation step (the first SO4 solution), whereby a solid phase and a second SO4 solution phase are formed, the solid phase containing a first fraction of metal hydroxides, which can be recovered,

- sulfide addition and subsequent precipitation of a precipitate from the hydroxide solution phase, the step also yielding a third SO4 solution,

- a poly sulfide treatment of the sulfide precipitate obtained from the poly sulfide treatment, in order to provide dissolved sulfides and a second fraction of metal sulfides, which latter can be recovered,

- a sulfuric acid treatment of the dissolved sulfides obtained from the poly sulfide treatment, whereby also the sulfides therein are precipitated, and can be recovered as a third fraction of metal sulfides,

20165972 prh 15-12-2016

- a step of concentrating the thus obtained solution phase in order to form a salt phase, followed by carrying out a thermal step on the formed salt phase, where a remaining portion of the metals form a mixture of metal sulfates and metal oxides, and

- finally a washing step carried out on the mixture of sulfates and oxides, whereby a non-soluble metal oxide phase and a solubilized sulfate phase are obtained, and can be recovered.

[0062] Figure 2 illustrates an alternative process scheme in accordance with an embodiment of the present invention. The process scheme of this Figure includes a step of roasting the solid phase obtained from the dissolution step, before sulfidization and flotation.

[0063] Said roasting step is intended to oxidize any elemental sulphur present in the solid phase obtained from the dissolution step, according to the following reaction (54):

(54) S(s) + 02(g) => SO₂(g) [0064] This step can be essential in certain cases, since many zinc processes recently developed result in jarosite fractions that are rich in elemental sulphur, while sulphur in its elemental form would have a negative effect on the subsequent sulfidization and flotation step.

[0065] It is to be understood that the embodiments of the invention disclosed are not limited to the particular structures, process steps, or materials disclosed herein, but are extended to equivalents thereof as would be recognized by those ordinarily skilled in the relevant arts. It should also be understood that terminology employed herein is used for the purpose of describing particular embodiments only and is not intended to be limiting.

[0066] Reference throughout this specification to one embodiment or an embodiment means that a particular feature, structure, or characteristic described in connection with the embodiment is included in at least one embodiment of the present invention. Thus, appearances of the phrases “in one embodiment” or “in an embodiment” in various places throughout this specification are not necessarily all referring to the same

20165972 prh 15-12-2016 embodiment. Where reference is made to a numerical value using a term such as, for example, about or substantially, the exact numerical value is also disclosed.

[0067] As used herein, a plurality of items, structural elements, compositional elements, and/or materials may be presented in a common list for convenience. However, these lists should be construed as though each member of the list is individually identified as a separate and unique member. Thus, no individual member of such list should be construed as a de facto equivalent of any other member of the same list solely based on their presentation in a common group without indications to the contrary. In addition, various embodiments and examples of the present invention may be referred to herein along with alternatives for the various components thereof. It is understood that such embodiments, examples, and alternatives are not to be construed as de facto equivalents of one another, but are to be considered as separate and autonomous representations of the present invention.

[0068] Furthermore, the described features, structures, or characteristics may be combined in any suitable manner in one or more embodiments. In this description, numerous specific details are provided, such as examples of lengths, widths, shapes, etc., to provide a thorough understanding of embodiments of the invention. One skilled in the relevant art will recognize, however, that the invention can be practiced without one or more of the specific details, or with other methods, components, materials, etc.

[0069] While the forgoing examples are illustrative of the principles of the present invention in one or more particular applications, it will be apparent to those of ordinary skill in the art that numerous modifications in form, usage and details of implementation can be made without the exercise of inventive faculty, and without departing from the principles and concepts of the invention. Accordingly, it is not intended that the invention be limited, except as by the claims set forth below.

[0070] The following non-limiting examples are intended merely to illustrate the advantages obtained with the embodiments of the present invention.

EXAMPLES [0071] In these examples, each step of the overall process is described with quantitative details of the composition, starting with the content of the raw materials, 5 shown in Tables 1 and 2.

[0072] The annual feed amounts of jarosite and dust have in the below calculations been selected to be 400,000 t/a and 20,000 t/a, respectively, and the processing time 8000 h/a.

20165972 prh 15-12-2016

Table 1. Raw material 1, i.e. the jarosite.

Moisture, t/si	215 385
Moisture, t/li	26,9
t/a. moist	615 385
t/h. moist	76.9
Moisture. “/<>	35.0
-Ξ	o o o o o
-Ξ	50.0
Raw material 1	Jarosite

Sr 87.62	O t~~ °' θ 2 H o o	MuO 70.937	_ o -H XO -H • o o ° ΜΊ · · O O
Ba 137.34	OOXO \\|- Ο Ο ΜΊ _o‘ XO rd \\|- T—Η Ο	O = si. rc θ'	cr rrd ^c2 oo un • XO o O O . O rd
( a 40.080	4.0 16 000 2.000 49.900	ms O 2 < O	o σ> en \O m > ö rd o rd
Al 26.982	o oo CT 00 \\|- XO O — O '/T	SiO₂ 60.085	4.3 17 115 2.139 35.605
Si 28.086	2.0 8 000 1.000 35.605	O $ T cd y: 22	_ Td CM Od O t~~ _ rC — .d ° 00 · · O O
S 32.064	12.7 50 863 6.358 198.286	-t- r\] o 5 J-. · CS Cd cc m CM	O O XO Γ· Tf ö ^Γ2 t CM O —
Ph 207.190	o g ο θ - § £	-r 0^1 O 2 * Ό 22	13.6 54 348 6.793 49.900
Cd 112.400	_ O 00 5 O CM t~~ o kO ο -H ° O Ö	f o UT £ o CT	4.4 17 564 2.195 7.240
Cu 63.540	_ o -r cm o o r~ • O ID o 00 · O	CM S*¹, O\ «? 2 — 00 ~ >0	00 — O Γ— θ - § 5
Zu 65.370	o o 2? o o o 2 N ° °- £· 00 —	O m cd w 2 — o/ = rc 0 CM	(N ’d- x — > > _o‘ O ΠΊ ΜΊ Γ*Ί Ö —
1 e 55.847	27.1 108 467 13.558 242.777	d S <D' 2 L- -H = *3S <>	7.4 29 501 3.688 15.298
rd o CT	O t~~ CM 2 O id • O ID o 00 · O CM	·/. o © ·- >0 .Ξ o s. θ	2.6 10 246 1.281 2.557
Xa 22.990	1.30 5 200 0.650 28.273	£ 00 © O g 2 — >0 Z	27.4 109 633 13.704 28.273
\ll4 18.039	1.4 5 589 0.699 38.729	·/. p r- = r- ”7 c*	37.2 148 639 18.580 38.729
1 o 8 S Ξ ~So	0/ /0 t/a t/h kmol/h	g/mol	0/ /0 t/a t/h kmol/h

(:i 69.720	40 16.0 2.000 28.686
hi 114.820	100 40.0 5.000 43.546
O	15 6.0 0.750 10.332
Au 196.967	0.5 0.200 0.0250 0.127
O Oi. >0 < l< o	150 60.0 7.500 69.528
g/mol	Λ ^S o i d M Λ ^3 E	Total 1 1	100.0 400 000 50
II 1.008	Π fN • XO ΜΊ ’d- ö '^r '	(hbO, 187.438	0.005 21.5 0.00269 0.0143
O 15.999	43.7 174 793 21.849 1 366	00 *' cr O xo s £	0.012 48.4 0.00605 0.0218
- :·	0.005 19.720 0.00246 0.0695	⁰⁰ O U o	0.002 8.645 0.00108 0.0103
Su 118.690	T> CM o o 2 S ° o o	Au 196.967	0.00005 0.200 0.000025 0.000127
Sh 121.75	o S g S ° ö ö	cr r- rd U cr Oi. _frj < -\|-	0.020 79.7 0.00996 0.0695
As 74.922	o o σ> \\|- O O X0 _o· XO Cd xo ö rd	SnO₂ 150.689	0.013 50.8 0.00635 0.0421
^w 00	rd o — O O O o o o o O 00 o o	... z-s σ\ O *= d S	0.048 191.5 0.0239 0.0821
Xi 58.71	OO ’xl- o 2 ^rr' 2 t O (-r^ O O ö ö ö	-. 2] ® ⁰⁰ (Λ <	oo cr ’d^- «/Ί rd xo cr 'e — n c^r ₍ö rd ö
Mu 54.938	_ O “ Ξ °' θ H H O o	Co() 74.932	cr o o — o o o o ö ö ö
M» 24.312	o r- — O 1^ «r, ö 5 A A o rd	XiO 74.709	O ΜΊ O O o o ö ö ö

91-08 -81-- 91- Had ZZ699I-08

Raw material 2______ t/a, dry Moisture. *7» t/h.dry t/a. moist t/h. moist Moisture, t/a Moisture, t/h

Dust 1 [Pl] 10 000 8.0 1.250 10 870 1.359 870 0.109

Dust 2 [P2]__10 000__8,0__1,250__10 870__1,359__870__0,109

Dust mixture [PS] 20 000 8.0 2.500 21 739 2.717 1 739 0.217

E

IT.

=

SJ

E ÖD o

OI

91-08-81--91. Had ZZ699I-08

Total 1		o © o © o		20 000		2.500
d 2 CU 'tf'	0.200 0.290	ΟΙ eq o	o o> C4 C4	ox	0.003 0.004	ό o o o’	00 Ό O O Ö Ö	© ©’
1 19.00	0.380 0.380	o 00 o	00 00 tn tn	X©	0.005 0.005	o o ©	0.250 0.250	o o in o’
•n □ £ tn	1.570 1.510	o Ι/Ί	n <n	00 ©	o CM o o O Ö	ox © ©’	0.554 0.532	X© 00 ©
( 12.01	0.710 0.850	o 00 ©	< n r- oo	x© ΟΙ	O O o o O Ö	o n o o’	0.739 0.885	eq X©
*. o O U £ £	O o o o o o O\' SO tn \\|-	42.500	3 900 4 600	© © ΟΙ 00	0.488 0.575	X© ©	3.053 3.601	Ι/Ί X© X©’
S 32.06	1.180 0.300	o o’	118.0 30.0	00	0.015 0.004	<3\ O ©’	0.460 0.117	©’
90'08 os	O o o o o o ö ö	o o o ©	o o Ö Ö	o ©	o o o o o o O Ö	O o o ©	o o o o o o Ö Ö	© o o ©
PM) 223.19	2.760 3.100	o m ox eq’	276.0 310.0	x© 00 ΟΙ	0.035 0.039	co o ©	0.155 0.174	00 eq ©’
C S C ?	O o O o o	ΟΙ © © ©’	o o ö		o o o o o o	o o o ©	0.0017 0.000	© o ©

91-02 -21-- SL Had ZZ699I-02

Example 1 - H2SO4 treatment [0073] A sulphuric acid treatment is carried out on the dust. The sulphuric acid is heated to a temperature of 200°C and mixed with the preheated (100-150°C) dust. The temperature of the formed mixture thus rises to more than 250°C. As a result, the oxides in the dust are sulphatized, the halogenides are decomposed and sulphatized at least to a degree of 70%. The water and the halogen hydrides are transferred to the gas phase, from where they are compressed using water washing. The reactions of this sulphuric acid treatment are further described below, in Tables 3-5.

Table 3. Reactions with sulfuric acid:

Reactions m ith ΙΙ₂ΝΟ₄	MeO(Me₂O.,)	11₂SO₄
kg/t	kmol/t	kmol/t	kg/t
(1) 2NaCl + H₂SO₄ =>	Na₂SO₄ + 2HC1	(NaCl)	25.39	0.434	0.217	21.3
(2) Na₂O + H₂SO₄ =>	Na₂SO₄ + H₂O		47.59	0.768	0.768	75.3
(3) 2KF + H₂SO₄ =>	K₂SO₄ + 2HF	(KF)	1.16	0.020	0.010	1.0
(4) K₂O + H₂SO₄ =>	K₂SO₄ + H₂O		12.76	0.135	0.135	13.3
(5) MgO + H₂SO₄ =>	MgSO₄ + H₂O		17.10	0.424	0.424	41.6
(6) CaF₂ + H₂SO₄ =>	CaSO₄ + 2HF	(CaF₂)	7.03	0.090	0.090	8.8
(7) CaO + H₂SO₄ =>	CaSO₄ + H₂O		30.65	0.547	0.547	53.6
(8) A1₂O₃ + 3H₂SO₄ =>	A1₂(SO₄)₃ + 3H₂O		4.55	0.045	0.134	13.1
(9) MnO + H₂SO₄ =>	MnSO₄ + H₂O		31.30	0.441	0.441	43.3
(10) ZnO + H₂SO₄ =>	ZnSO₄ + H₂O		311.60	3.829	3.829	375.6
(11)CuO + H₂SO₄ =>	CuSO₄ + H₂O		2.50	0.0314	0.0314	3.08
(12) NiO + H₂SO₄ =>	NiSO₄ + H₂O		0.150	0.00201	0.00201	0.197
(13) CoO + H₂SO₄ =>	CoSO₄ + H₂O		0.050	0.00067	0.00067	0.065
(14) PbO + H₂SO₄ =>	PbSO₄ + H₂O		29.30	0.131	0.131	12.9
(15) Fe₂O₃ + 3H₂SO₄ =>	Fe₂(SO₄)₃ + H₂O		425.00	2.661	7.984	783.0
				14.745	1446.2
H₂SO₄ consumption	20 000 t/a		1446.2	kg/t	28924	t/a

20165972 prh 15-12-2016

Raw material t/a. Moisture, t/h. t/a. t/h. Moisture. Moisture, dry % dry moist moist t/a t/h
[SS] Feed mixture H₂SO₄ (95%)	20 000 30 446	8.0 5.0	2.500 3.806	21 739 32 048	2,717 4.006	1739 1602	0.217 0.200
Mixture	50 446	6.2	6.306	53 787	6.723	3342	0.418

Reactions (1)-(15)	CoelTicient (sulfate/oxide, chloride, fluoride)	Reaction degree 0/ /0	Change in mass 0/ /0
(1) 2NaCl + H₂SO₄ =>	Na₂SO₄ + 2HC1	1.215	100	0.546
(2) Na₂0 + H₂SO₄ =>	Na₂SO₄ + H₂O	2.292	100	6.148
(3) 2KF + H₂SO₄ =>	K₂SO₄ + 2HF	1.500	100	0.058
(4) K₂O + H₂SO₄ =>	K₂SO₄ + H₂O	1.850	100	1.084
(5) MgO + H₂SO₄ =>	MgSO₄ + H₂O	2.986	98	3.328
(6) CaF₂ + H₂SO₄ =>	CaSO₄ + 2HF	1.744	70	0.366
(7) CaO + H₂SO₄ =>	CaSO₄ + H₂O	2.428	95	4.158
(8) A1₂O₃ +3H₂SO₄ =>	A1₂(SO₄)₃+3H₂O	3.356	60	0.643
(9) MnO + H₂SO₄ =>	MnSO₄ + H₂O	2.129	95	3.357
(10) ZnO + H₂SO₄ =>	ZnSO₄ + H₂O	1.984	99	30.355
(11)CuO + H₂SO₄ =>	CuSO₄ + H₂O	2.007	98	0.247
(12) NiO + H₂SO₄ =>	NiSO₄ + H₂O	2.074	90	0.014
(13) CoO + H₂SO₄ =>	CoSO₄ + H₂O	2.068	90	0.005
(14) PbO + H₂SO₄ =>	PbSO₄ + H₂O	1.359	95	0.999
(15) Fe₂O₃ +3H₂SO₄ =>	Fe₂(SO₄)₃+ H₂O	2.504	93	59.446
110.8

20165972 prh 15-12-2016

Table 4. The sulfatized dust

-w O E-	95.8 40 279 5.035
05 o £ ?! <υ L-	o \i- \i- r— o> x if- 05 rd 20
-I- ^rd o '^r- w £ s “ CT	o c t r-i X tn O'- — ; r- ο cr ö Ö
-I- O 2? y 2 o	O Cd CT o o n t o §5 o o Ö Ö	π Ξ y	rd o o> 3 3 r-H Ö
- £ o £ £ Y s 12	— 50 Ο · η o r- \T o o o ° o o A Ö o	rd O^^ ϋ tn —	N >n Ό o\ 30 _ 'Λ, Ο -Ι- Ο o
-f ^d o S z Z 12	cr oo rd rn o. - > Ö ° ° o o	O'- X O A rd £	O 05 \\|- \\|r- rd o 20 O O -H ö ö A o
-t ^4 o s? y A S S	Cd O O 00 — \T cr rcn rd tn ^rd rd — O'	rd cr ~ A A ?	o o o r- o O -h o o o Ö Ö g o
φ S y °. - —< ~ 12	— \O 00 X O 20 tn ~( cr ^0x1 A A — O —	O'- 3·	— ο ο ·η o o o o o o ö ö A o
oo d a y cn — CO <	^f- CO CO Γ-^- oo γί c Ö ~ °. A o o	>n C Ä =	rd o 20 o O -h o o o ö ö A o
U g°	o rd tr> x -TT O O Ö A A o o	© 2 Ss oc	x rd oo r\\|- 20 o tn o O> ö ö A o
-f <N O 2 y « i£ Φ 2i	r- tri oo o r- x 05 t, cn A O —	3 2	rd r- cr o tn o o tn ö ö A o
y 2 si. - - 2!	x <-h tri O'er o rd cr rd ° A O —	d 2 < -	20 tn 20 x cr o \\|o o \\|- ö ö A o
s X •T)	o o o o O O 3 ° § 2 Ö	o =	cr — \T x r- cr o 20 o o o Ö Ö Ö
-F Ό Γ5 y 2 2' 2	r- cr -\|rd o 20 50 ; tri o cr ö o	o A &Λ O	50 — rd I—Η Ο -H o o rd ö ö A o
— CT - _x & Τι	OOOO o’ A = o o	-1ri — o ^.- CM y o	20 o 20 rd tn rd 05 rd A O
d 3 y · <N	20 X O rd O O- 'G .C cr -r rd O rd
O X 1-1 — s. c 3 3 >_n-q 00	A O C3 -9 Ξ O^x is 1^3 —4	^—. ÖD	o _xo Λ g Ϊ2 5 Λ

-=	5.035 0.219	5.253
t/a	40 279 1749	42 028
	95.8 4.2	100.0
-w (Z) 3 Ό O .N '3 3 y:	Sulfatic Oxidic	Total

91-08 -81-- 91- Had ZZ699I-08 [0074] In addition to the sulphates, also NaCl, KF and CaF₂ are considered to belong to the sulphate phase.

Table 5. Halogenides

(his phase	iro	IK 1	III
g mol	18.015	36.461	20.006
t/a	1739	317	58
t/h	0.217	0.040	0.007
kmol/h	12.067	1.086	0.365

20165972 prh 15-12-2016

Example 2 - SO₂ dissolution [0075] Jarosite and the sulphatized dust are fed to an SO2 dissolution step. The temperature in said dissolution is about 90°C, whereby the reactions of the following listing take place, affecting the components of the jarosite and the components of the sulphatized dust. In this reaction listing, it has been assumed that all reactions (16) - (29) have a reaction degree between 0.95 and 1.00.

(16) 2A[Fe₃(SO4)2(OH)6] (s) + 3 SCh(aq) => A₂SO4(aq) + 6 FeSO4(aq) + 6 H2O (A = NH4, Na, K) (17) Fe₂(SO4)3 (s) + SO2 aq) + 2 H2O => 2 FeSCh (aq) + 2 H2SO4 (aq) (18) MeFe₂O4 (s) + SO2 (aq) + 2 H2SO4 (aq) => MeSCh (aq) + 2 FeSCh (aq) + 2 H2O (Me = Zn, Cu, Cd) (19) AI2O3 (s) + 3 H2SO4 (aq) => Ah(SO4)₃ (aq) + 3 H2O (20) MgO (s) + H2SO4 (aq) => MgSCh (aq) + H2O (21) MnO (s) + H2SO4 (aq) => MnSCh (aq) + H2O (22) NiO (s) + H2SO4 (aq) => NiSCh (aq) + H2O (23) CoO (s) + H2SO4 (aq) => CoSO4 (aq) + H2O (24) AS2O3 (s) + 3 H2O => 2 H3ASO3 (aq) (25) Sb2Ch (s) + H2O => 2 HSbCh (aq) (26) SnCh (s) + SO2 (aq) => SnSCh (aq) (27) GeCh (s) + SO2 (aq) => GeSCh (aq) (28) ImCh (s) + 3 H2SO4 (aq) => In₂(SO4)₃ (aq) + 3 H2O (29) Ga₂O3 (s) + 3 H2SO4 (aq) => Ga₂(SO4)3 (aq) 3 H2O

Table 6. Dissolution

[0076] After the SO2 dissolution, the solid and solution phases are separated. The solid phase is washed and the washing solution is added to the solution phase.

L08 -81-- 9 L Had ZZ699I-08

o § \r. -S' oo —	o o o o o _ o O O O o Ö Ö Ö
o 2 00	o o o 0 0^0 O O O o Ö Ö Ö
\aCI 58.443	o o o 0 0^0 O O O o o o o
ςζ9 zzi7 ’VosFKJ)	0.014343087 0.006 49 0.036
o s 7!	0.0218 0.011 90 0.066
-r C4 A >0	0.0103 0.002 14 0.0102
o Zj >0 2	0.0103 0.002 14 0.010
-f CM O £ ^r -f· = 3	0.0417 0.009 72 0.053
g/mol	kmol/h t/h t/a kg/m₃

X ©o •ΖΊ	000 £ £000 0 900 0
As 74.922	0.0267 0.0020 16 0.01
Al 26.982	0.363 0.0098 78 0.07
Mn 54.938	0.0734 0.0040 32 0.03	Au 196.967	r- μί o M (N O L —¹ O CS . Ö Ö Ö
	0.0623 0.0015 12 0.01	o Ci. 00 o	69.528 7.500 60.0 502
Cd 112.400	0.0036 0.0004 3 0.00	o S ~So	S g Λ Ϊ2 ft
( 11 63.540	0.0330 0.0021 17 0.01	00 — 00	0.135 0.0026 21 0.02
Zn 65.370	CM , oo O rl O O Tl · • · CM o o o	— '^r'	0.0695 0.0025 20 0.02
Sr 87.620	ΜΊ ο ΓΊ ΐΛ) θ. ο Ö o o	00 — o — °.	205.42 0.2071 1 656 1.39
Ba 137.340	m cm o H ’t o 2	o> o> Φ wS	441.1 7.057 56 460 47.28
1 e 55.847	13.070 0.730 5 839 4.89	3 y:	60.934 1.954 15 630 13.09
Si 28.086	36.901 1.036 8 291 6.94	Sn 118.690	0.0004 0.00005 0.4 0.000
Ca 40.080	51.492 2.064 16 510 13.83	Sb 121.75	0.002 0.0002 2 0.001
Ph 207.190	oc oc Zt — Ό Ό IT) T, Ά _n Γ4 2	/-S 00 •ΖΊ	0.002 0.0001 1 0.001
Dissolution residue g/mol	kmol/h t/h t/a 0/ /0	o s ~So	kmol/h t/h t/a 0/ /0

91-02-δ 1--G I- Had ZZ699I-02

Example 3 - Sulphidization of the dissolution waste and flotation of the sulphide phase [0077] In the sulphidization and flotation step, the following reactions (30) and (31) 5 take place:

(30) PbSCh (s) + Na₂S (aq) => PbS (s) + NazSCh (aq) (31) Ag₂SO4 (s) + Na₂S (aq) => Ag₂S (s) + Na₂SC>4 (aq) [0078] The solid dissolution waste is first suspended into water to form a slurry.

Subsequently, sodium sulfide is added to the sludge (see reactions (30) and (31)) in an amount equivalent to the lead and silver, and the sludge is floated. The sulfide phase and the gold are floated.

[0079] In the flotation, it is assumed that the yield of lead in comparison to the sulfide phase is 97%, and the yield of silver and gold is 95%. No significant amounts of minor components of the dissolution waste, such as gypsum and S1O2, are included in the sulfide waste, although trace amounts are inevitably carried to the sulfide phase.

[0080] Solution 1 (dissolution solution) and 2 (sulfidization and flotation solution) are combined to form solution 3 (see the following Table 8).

20165972 prh 15-12-2016

Table 8

	O © O ri	rs o o o o 0 0^0 O Ö Ö
XiO 74.709	kD O C<) o o o o o o O Ö Ö
0 °° e/) Γ» < <25	0.0133 0.003 21 0.021
Abi); 101.961	0.1813 0.018 148 0.1
MnO 70.937	0.0734 0.005 42 0.0
O - SL CO S	0.0623 0.003 20 0.0	Au 196.967	800 0100 £100'0 £900'0
05 f'} yrj rs	0.0036 0.000 4 0.0	z> Ci. >0 < \|<	kD ΜΊ C Γ O i/^ m rs cn o
( TiO 79.539	0.0330 0.003 21 0.0	on	xi o δ g Λ ϊι a
Total	12.713 101 701 100.00	0 = * κ	rs o rn 7 cr H H S o o	ssi:_lK	12.724 101 789 100.00
00 05 — 00	0.135 0.0026 21 0.02	-t o S ΐ < y 22	-r ID r- o 04 oo in -h er · . . oo ° o o	Au 196.967	0.000006 0.0000 0.01000 0.00001
en _ ΜΊ un en	0.0035 0.0001 1 0.00	-i- es o <73 · π cc « r'> “ CM	kD O ©5 '^ \\|· — r^· ^rr). rs o rs	Ao(l 143.323	0.0035 0.0005 3.986 0.004
II 1.008	205.97 0.2076 1 661 1.63	., r 1 a. O ko 05 Li. Τι	•/Ί Tf 05 m \\|- \\|- rs Μη o cn kD 00	Cal k 78.077	0.0675 0.0053 42 0.041
05 05 c un	412.6 6.601 52 810 51.93	X’ oo o =· ''^J- §	36.901 2.217 17 737 17.4	l»b() 223.189	0.0164 0.0037 29 0.029
S 32.064	53.762 1.724 13 790 13.56	o X r-l U O iL' y -h U	51.492 8.865 70 924 69.7	o - T)	0.0683 0.0038 31 0.030
Su 118.690	0.0004 0.00005 0 0.0004	04 N 00 0 40 c o y 'o	n^- — ·η o o o 0 0^0 o o o Ö Ö Ö
Sb 121.75	0.002 0.00020 2 0.002	-t cs >*S >D y £ s	ΓΛ „ -f- \|r o CM O 00 · . . ir, O o o	.. xi —	0.002 0.0005 4 0.004
g/mol	kmol/h t/h t/a 0/ /0	g/mol	kmol/h t/h t/a 0/ /0	75 CD	”o E x _xo ^9W-^I-

o rS 00 = 3	0.0435 0.005 40 0.0217
o	££000 9 1000 £0100
Sn 118.690	0.0417 0.005 40 0.022
Sb 121.75	m O 00 kD O N 'C X —H O —O o ö ö
m m o L· ⁰⁰ ^w >r>	0.0168 0.001 8 0.0043
©o ΜΊ	o> \\|- rs oo xO O m — O O o o o o
As 74.922	cr x n^- — \\|· 05 00 k© O — 'C X CS Ö r-H ö
AI 26.982	O MS M rl- ie M m X0 ΜΊ O o
Mn 54.938	o c-- m m -r o t c 05 — OC “t ö ö
Mg 24.312	•/Ί Tf Tf m μί r- o> rs o o m m en o o
Cd 112.400	\i- o r- μί r- rs ms oo O O o ö ö
(u 63.540	04 CO CO Γ— o r i -r 40 — OC —C ö ö
Zn 65.370	24.469 1.600 12 797 6.956
le 55.847	243.013 13.572 108 572 59.019
K 39.102	'G x > o. oo rs rs rs o μί en O o
Xa 22.990	— rs x© k© > — 05 en en — X X OO 00 -f-
XI l₄ 18.039	38.729 0.699 5 589 3.038
= o — O i e OTdcT⁰	Έ C<-> o E Ξ s a

o o = -H - !2	O CC CC \\|· \f OS \f Γ-· D N r₍ n o rq
O ΓΧ j·. Oi. Z2 S 2	T) 00 C4 OS TS \D “t O O CC OS T) CCi OCS
( \ISO4 208.462	\\|- SD 00 r- cc ts -H O O> -H ,—: ,—: o o o
-I- cm ö ° ζΛ i?· u 12	OS 00 00 Tt — TS \D CM vD CM O — o rq	o ζ/2 °. -C¹ oo — o.	O O o o o _ o O O O o o ö ö
-r CM O g y _ S S	o, 00 SD o r- g σ! cci g	o L. 5 xJ ΜΊ	o o _o o o _ g o ö °
-f c y: _: '/Ί	CC . ~ SD SD — _ CM CC °. O> CC MC CC TS O o> sd CC _	_ CC - Ti	o o _o o o _ g o ö °
T M2 <T> C/5 U £ g	CM SD O TS Tf 00 OS Tf SD CM CM CM o rq	T) o CM y	-f g _ -Ό g 2 o ° ö
”f O g y -: « g s 3	T,rc σ- 00 X? 00 CD g 3 CM 2	·*. o >0 ί- 1^' H Ti	oo __ o CN O \\|- O.^O o ° ö
O id / -e £ £ y —	_o o t~~ M2 g -f O O S *O O o< _r > CM cm — CM —	ö un >0	S g § §² S
T) Qs ™ 00	g £ s 2 s s	-r <N O £ ^r -t= 3	3 § £ o O ° °
00 — o — o	ΜΊ O \\|· \\|· 'Cj O SD cc ^! cc r- SD O O	O »ci .c C y -f= 12	CC T) o^ sd C4 z? O -H o O -H ,-: o o o
00 o> M 00	o o o o o _ o O O O o ö ö ö	-I- T) O y *- O ”1· (J T)	s g O o CM °. O ° °
CC T) T) CC	o o o o o _ o O O O o ö ö ö	-f O £ ί ^t/Γ ^,/Ί	cn -h r- sD — xr) ^1o o So o o ö ö
CM O O y ko O)	O 'Z Cl g C4 ~ ~ ΜΊ rq _r<1 \\|- cc cc ^{C i} CM —	-· ΉO «ΐr. O) “C ID = Ί	CC CC CC r-· -t cc sd -t sd cc sd ’d^- r] o n
O - s - £ SD	00 g 00 CM g O ö ° ö	**> 5 3 £ CM <	SD 00 (N r- o sd ’d- SD 00 SD -h ö -r r4
~a S ~So	Έ CC) ”6 E E ~So Λ > Ϊ2 Λ	~a E ~So	CC) ~o E E 'oo Λ Ϊ2 Λ

91-08 -81-- SL Had ZZ699I-08

20165972 prh 15-12-2016

Example 4 - The separation of indium, gallium ja germanium [0081] The indium and gallium are separated from Solution 3 by a hydroxide precipitation, by adjusting the pH to a level of 3.5-4, using Mg(0H)₂ as the pH adjustment agent. The temperature of the solution is between 80 and 90°C. Other possible pH adjustment agents are ZnO, Walz-oxide (or the ZnO therein), CaO, Ca(OH)₂ or CaCO₃.

[0082] The hydroxides In(0H)₃ and Ga(OH)₃ are less soluble compared to A1(OH)₃, which is also one of the least soluble hydroxides of the solution phase (when no ferric ions 10 are present).

[0083] The values of the solubility products of the hydroxides varies to some extent, depending on their source. If the solubility product values for the indium and gallium hydroxides are equal to or lower than 10(exp(-36)), and if the corresponding value for aluminium hydroxide is 10(exp(-31)), it is possible to obtain a sharp distinction. If the pH adjustment range is 3.5-4, the precipitate will contain also aluminium hydroxide.

[0084] Germanium (and gallium) can be precipitated completely from the solution in the form of a tannine. When assuming that indium, gallium and aluminium hydroxides are 20 precipitated in a pure form, and germanium is precipitated in the form of its hydroxide, the following reactions take place:

(32) In₂(SO4)3 (aq) + 3 Mg(0H)₂ (s) => 2 In(0H)₃ (s) + 3 MgSCh (aq) (33) Ga2(SO₃)₃ (aq) + 3 Mg(OH)₂ (s) => 2 Ga(0H)₃ (s) + 3 MgSCh (aq) (34) GeSCh (aq) + Mg(0H)₂ (s) => Ge(OH)₂ (s) + MgSO4 (aq) (34’) Al₂(SO₄)₃(aq) + 3Mg(OH)₂(s) => 2A1(OH)₃(s) + 3MgSO₄(aq) (35) H₂SO4 (aq) + Mg(0H)₂ (s) => MgSCh (aq) + 2 H₂O [0085] The precipitated hydroxides are separated from the solution, and are washed. 30 The washing solution is added to the solution phase. Thus, a precipitate containing In, Ga and Ge hydroxides is obtained, and a Solution 4.

11.0 18.015	851 0.106 5.901
S o « S ÖD	t/a t/h kmol/h

Table 9

	lotal 1	3 402.031 0.4253 100.0
lotal 1 1	3 402.031 0.4253 \|00 0	on 17.007	2195.883 0.27449 16.1392 64.5
⁼ S 9- §. — 00	3307.736 0.4135 5.301 97.2	AI 26.9815	1 144.148 0.14302 5.301 33.6
s· z ° 4) O	8.812 0.0011 0.0103 0.3	(ie 72.590	6.000 0.00075 0.0103 0.2
(.:1(()11)3 120.742	27.709 0.0035 0.0287 () 8	(ia 69.720	16.000 0.00200 0.0287 0.5
2. es — Tf — oo O '/S = -	57.775 0.0072 0.0435 1 7	In 114.820	40.000 0.00500 0.0435 1.2
4J (J O o, « - -ΐ Ξ 2 '* ’s G 2 -s 2 , Ό <υ tt = ~So	t/a t/h kmol/h	g/mol	t/a t/h kmol/h 0/ /0

Sn 118.690	0.042 0.00495 40 0.022	O jr m OI. o - 2	(T) 00 rs 00 (T) Ό \\|· 08 O C<) 08 ΜΊ cc ό n
Sh 121.75	0.163 0.01980 158 0.086	-i- rS O XD y o 00 CJ ° Cd	\\|- XO 00 c*c ~ 'r, -H O O O o
Co 58.933	0.017 0.00099 8 0.004	T cl O ° x 5 O\ U £	08 oo oo en — 'r, \O rs xO rs O — ^-1 o rq
Xi 58.71	0.069 0.00406 32	-» O 2? y. · >i S	24.469 3.950 31 601 17.170
As 74.922	2.643 0.198 1 584 0 8b 1	-f o S	243.013 36.916 295 326 160.461
AI 26.982	ci o O 0 0^0 ö ö o	-f o * £	rs xo o \iTf 00 08 Tf xo rs rs rs o rq
κ e «Z 08 •Z	O t~~ rc -f- O 0Λ -H <r> -t- ö ⁰⁰ o	”f O y: °. J CM / 3	24.185 3.435 27 483 14.932
rs £	'/S \\|- . '/η r- \T rs o o O8 π CO Ö '^r' O	O ID </) *T MO =	19.364 2.830 22 640 12.301
O o r i	\\|- O T. r- rs κ — o 3 ö ö o	o _ yi	12 770 230.060 1 840 477
Cu 63.540	1.619 0.103 823 0 447
Zn 65.370	24.469 1.600 12 797 b 053	II 1.008	163.005 0.16430 1 314
le 55.847	243.013 13.572 108 572 58 001	o =>. J~. O O\	319.630 30.70417 245 633 133.462
K 39.102	00 r- κ 2 oo rs rs ·/-. π rs o t. rr · CO ö -h g	000 0 000 0 00000 0 0000 0
Xa 22.990	n 30 Ξ S S3 00 A	In 114.820	000 0 000 0 00000 0 0000 0
08 — o	38.729 0.699 5 589 3 <>37	(ie 72.590	0.0103 0.00075 6.0 0.003
T Z O = s O j ⁰⁰	kmol/h t/h t/a kg in	g/mol	”o S 8 ~So

91-08 -81-- SL Had ZZ699I-08

91-02-δ 1--G I- Had ZZ699I-02

Example 5 - Sulfide precipitation [0086] The sulfide precipitation is carried out by adjusting the pH of the solution, for example using Mg(0H)₂, so that no significant amounts of iron (Fe²⁺) is precipitated. The reactions taking place during the precipitation include the following:

(36) 2H₃AsO₃ (aq) + 3H₂S (aq) => AS2S3 (s) + 6 H2O (37) 2HSbCh(aq) + 3H₂S (aq) => Sb₂S₃ (s) + 4 H2O (38) SnSCh (aq) + H2S (aq) => SnS (s) + H2SO4 (aq) (39) C11SO4 (aq) + H2S (aq) => CuS (s) + H2SO4 (aq) (40) CdSO4 (aq) + H2S (aq) => CdS (s) + H2SO4 (aq) (41) ZnSCh (aq) + H2S (aq) => ZnS (s) + H2SO4 (aq) (42) H2SO4 (aq) + Mg(0H)₂ (s) => MgSCh (aq) + 2 H2O

20165972 prh 15-12-2016

Tabic 10

Starting materials	H.sAsO.s	IISbO₂	S11SO4	C11SO4	CdSO₄	ZnSO₄
g 'mol	125.944	154.757	214.752	159.602	208.462	161.432
t/a	2 663	201	72	2 068	291	31 601
t/h	0.333	0.025	0.009	0.258	0.036	3.950
kmol/h	2.643	0.163	0.0417	1.619	0.174	24.469
Reaction	Sulfide							To
products	precip. 1	.\s₂S.,	sb_:s.,	SnS	CuS	CdS	ZnS	solution	ll₂O	ll₂SO₄
g/mol		246.038	339.692	150.754	95.604	144.454	97.434		18.015	98.078
0/ /0	100.0	11.1	0.9	0.2	5.3	0.9	81.6
t/a	23 385	2 601	221	50	1 239	202	19 073		8 772	20 639
t/h	2.923	0.325	0.028	0.006	0.155	0.025	2.384		1.096	2.580
kmol/h		1.321	0.081	0.0417	1.619	0.174	24.469		60.863	26.305
		As	Sb	Sn	Cu	Cd	Zn	S
g/mol		74.922	121.750	118.690	63.540	112.400	65.37	32.064
0/ /0	100.0	6.8	0.7	0.2	3.5	0.7	54.7	33.5
t/a	23 385	1 584	158	40	823	157	12 797	7 827
t/h	2.923	0.198	0.020	0.005	0.103	0.020	1.600	0.978
kmol/h		2.643	0.163	0.0417	1.619	0.174	24.469	30.513

Reagents	1 l₂S	Mg(OI l)₂
g/mol	34.080	58.327
t/a	8 319	12 274
t/h	1.040	1.534
kmol/h	30.513	26.305

Reagents g/mol	(XlhhS 68.136	S 32.064	ll_:SO₄ 98.078	IhO 18.015
t/a	2 316	730	3 334	93 542
t/h	0.290	0.091	0.417	11.693
kmol/h	4.250	2.847	4.250	649

Sull'ide solution	(XH₄),SO₄	irs	iro
g/mol	146.145	34.080	18.015
kmol/h	4.250	4.250	649
t/h	0.621	0.145	11.693
t/a	4 969	1 159	93 542
kg/m3	53.117	12.387

[0087] The obtained sulfide precipitate 1 is treated with an ammonium polysulfide solution, whereby AS2S3, Sb₂S₃ and SnS dissolve, whereas CuS, CdS and ZnS remain in solid form.

(43) AS2S3 (s) + 3 (NH4)₂S (aq) + 2 S => 2 (NH4)₃AsS4 (aq) (44) Sb₂S₃ (s) + 3 (NH₄)₂S (aq) + 2 S => 2 (NH4)₃SbS4 (aq) (45) SnS (s) + (NH₄)₂S (aq) + S => (NH4)₂SnS₃ (aq) (Ammoniumpolysulfide: (NH4)₂Sn(n = 2 ... 5))

20165972 prh 15-12-2016

Table 11

Sull'ide precipitate 2 g/mol	CuS 95.604	CdS 144.454	ZnS 97.434	lotal
0/ /0	6.0	1.0	93.0	100.0
t/a	1 239	202	19 073	20 513
t/h	0.155	0.025	2.384	2.564
kmol/h	1.619	0.174	24.469
	('11	Cd	Zn	S	lotal
g mol	o3 54(i	112.4(H)	65.37	32.004
0/ /0	4.0	0.8	62.4	32.8	100.0
t/a	823	157	12 797	6 737	20 513
t/h	0.103	0.020	1.600	0.842	2.564
kmol/h	1.619	0.174	24.469	26.263

[0088] The solid and solution phases are then separated, whereby the solid phase is washed using a solution based on ammonium polysulfide, and the washing solution is combined with the solution phase, i.e. with Solution 5.

[0089] Sulphuric acid is added to the thus obtained solution phase, whereby the sulfides of arsenic, antimony and tin are precipitated from the solution (reactions (46) (48)). After these steps, sulfide precipitates 2 and 3 are obtained, as well as a sulfide solution, which can be recycled and reused.

(46) 2 (NH4)₃AsS4 (aq) + 3 H2SO4 (aq) => AS2S5 (s) + 3 (NH4)2SO4 (aq) + 3 H2S (aq) (47) 2 (NH4)₃SbS4 (aq) + 3 H2SO4 (aq) => Sb₂S₅ (s) + 3 (NH4)₂SO4 (aq) + 3 H2S (aq) (48) (NH4)2SnS₃ (aq) + H2SO4 (aq) => SnS2 (s) + (NH4)2SO4 (aq) + H2S (aq)

20165972 prh 15-12-2016 o CO

Table 12

	lotal 1	100.0 3 602 0.450
loini	100.0 3 602 0.450	s 32.064	o oo rΠ Γ4 C4 o> O 00 C4 O - o I-’
00 y oo s. S	1.7 61 0.008 0.0417	o £ y od	1.1 40 0.005 0.0417
»s -O CO y o	CO CO CO CO 00 U CN θ· θ·	Sb 121.750	4.4 158 0.020 0.163
SO y S cn' _o* < CO	o £ 2 <N ^1- CO 04 (-O Ö	336T£ s\	, Tf- 00 CO H 00 04 ^f^f- ir> 40 —i o’ cl
(*> ’C Ξ Ξ o '= s	0/ /0 t/a t/h kmol/h	g/mol	0/ /0 t/a t/h kmol/h

iro 18.015	12 770 230.060 1 840 477
o °. y ko 04	293.282 28.173 225 385 122.46
C*P δ ^w 00 •ΖΊ	— o 2 O O ⁰⁰ O o °	-i- ΜΊ O 2 y 2 ο ”1· (J	O i—H O O fxj o Ö Ö Ö
\i 58.710	θ'-f- S S o O O o o	T <VI O £ £ A y Zi	σ> -h r- so — O O oo O Ö Ö Ö
Al 26.982	<4 O O O O O o' Ö O	5 1 6 d	£2 L' cm ~ g 40 o o o °
Mn 54.938	1.940 0.107 853 o 4b	d § \r. °. = -H 7 £	O CP CP \i- σ\ \i- Lj O> 04 ΓΊ O 04
Γ4 Cl “ ** ’d- C4	$ ? _s pj o O ' en o '^r ' °	d y si. o ~ Pi	ΜΊ 00 04 UO S0 2 o co σ\ ~ CO O 04
le 55.847	243.013 13.572 108 572 58 w	- o>	243.013 36.916 295 326 160.46
K 39.102	3.285 0.128 1 027 I) 56	-r ο Ό »3 * 2	\\|- Ό) 00 CO 00 OSO 04 04 · o 04
\<l 22.990	_rr ^r<: 2 J £ - 00	-t o y °. y 3	24.151 3.430 27 443 14.91
o> -7 ^r<) — f 00	38.729 0.699 5 589 3 ()4	O O4 y co _7 cm — CO y -w	19.364 2.559 20 470 11.12
Solution 5 g/mol	”o .= 8 ~Sb Λ ί Ϊ2 24	g/mol	kmol/h t/h t/a kg/m³

91-02-SL-9L Had ZZ699I-02

Example 6 - Evaporation crystallization

91-08 -81-- 91- Had ZZ699I-08

91-02-21--91- Had ZZ699I-02

Example 7 - Thermal treatment [0091] The salt phase is carried to a thermal phase, where the following reactions take place:

(49) (NH4)₂SO4 (s) + O2 (g) => N2 (g) + SO2 (g) + 4 H2O (g) (50) 2 FeSO4 H2O (s) => Fe₂O₃ (s) + 2 SO2 (g) + 1/2 O2 (g) + 2 H2O (g) (51) MgSO4 H2O (s) => MgSO4(s) + H2O (g) (52) MeSO4 H₂O(s) => MeO (s) + SO₂(g) + 1/2 Ch(g) + H2O (g) (Me = Mn, Ni, Co) (53) A12(SO4)₃-6 H2O (s) => AI2O3 (s) + 3 SO2 (g) + 3/2 O2 (g) + 6 H2O (g) [0092] In the calculations it has been assumed that the iron, manganese, nickel, cobalt and aluminum are completely turned into their oxide forms, whereas magnesium 15 remains as a sulfate.

Table 14

Reaction product g mol	Xa_:SO₄ 142 ()41	K,SO₄ 174 2bh	M«SO₄ I2O 374	Fe_:O., 150 oo2	MnO 7o 037	AI,O., 1 (i\| Ob\|	XiO 74 Too	(·<>() 74 032	Summa
kmol/h	24.185	1.642	3.055	121.506	1.940	0.013	0.069	0.0168
t/h	3.435	0.286	0.368	19.404	0.138	0.001	0.005	0.001	23.638
t/a	27 483	2 290	2 942	155 229	1 101	11	41	10	189 106
0/ /0	14.53	1.21	1.56	82.09	0.58	0.006	0.022	0.005	100.0

20165972 prh 15-12-2016

SO, to gas phase g/mol	SO, 64.063	11,0 18.015
kmol/h	264.4	325.6
t/h	16.94	5.87
t/a	135 527	46 931

[0093] The reaction product obtained after the thermal step is carried to a water washing step, whereby the soluble components are transferred to the solution phase, and the non-soluble oxide phase (mostly containing Fe2C>3) forms an acceptable iron concentrate.

Table 15

To solution phase g/mol	Xa 22.990	K 39.102	Mg 24.312	SO₄ 96.062
t/a	8 896	1 027	594	22 196
t/h	1.112	0.128	0.074	2.775
kmol/h	48.371	3.285	3.055	28.883

Iron concentrate g. mol	l-e/)., 159.092	MnO 70.937	AhO.; 101.961	XiO 74.709	CoO 74.932	Sum in a
0/ /0	99.26	0.70	0.007	0.026	0.006	100.00
t/a	155 229	1 101	11	41	10	156 392
t/h	19.404	0.138	0.001	0.005	0.001	19.549
kmol h	121 5<>n	1 O4(>	o o 13	o i inn	() ()\|bX
	le	Mn	Al	Xi	Co	()	Massa
g/mol	55.847	54.938	26.982	58.710	58.933	15.999
0/ /0	69.42	0.55	0.00	0.02	0.005	30.00	100.00
t/a	108 572	853	6	32	8	46 921	156 392
t/h	13.572	0.107	0.001	0.004	0.001	5.865	19.549
kmol/h	243.013	1.940	0.027	0.069	0.0168	366.585

Table 16. Water fed to the washing step

Water	ll₂O
g/mol	18.015
t/a	378 212
t/h	47.276
kmol/h	2 624

20165972 prh 15-12-2016

Washing

solution g mol	Xa 99()	K 39.102	Mg 24.312	S()₄ 96.062	IhO 18.015
kmol/h	48.371	3.285	3.055	28.883	2624
t/h	1.112	0.128	0.074	2.775	47.276
t/a	8 896	1 027	594	22 196	378 212
kg ni3			1 5^	58.69
	Xa₂S()₄	K₂SO₄	MgS()₄
g/mol	142.041	174.266	120.374
kmol/h	24.185	1.642	3.055
t/h	3.435	0.286	0.368
t/a	27 483	2 290	2 942
kg/m3	72.66	6.05	7.78

Example 8 - Recirculation [0094] Certain components can be recirculated in the process, particularly in case all of the above mentioned process steps are carried out in series as described. These components include sulfur dioxide (SO₂), sulfuric acid (H2SO4) and the sulfide solution containing ammonium sulfate ((NH₄)₂SO₄) and hydrogen sulfide (H₂S).

Table 17. Recirculation

g mol	SO, 64.063
t/a	65 410
t/h	8.176
kmol/h	127.628

t/a	54 904
t/h	6.863
kmol/h	69.975

g. mol	(MI₄hSO₄ 146.145	ll,S 34.080	11,() 18.015
kmol/h	4.250	4.250	0
t/h	0.621	0.145	0.000
t/a	4 969	1 159	0
kg/m3	53.117	12.387

Example 9 - Product yields [0095] In case all of the above mentioned process steps are carried out in series as described, the following products can be obtained, for example in the following yields, as obtained in the experiments carried out by the inventors.

20165972 prh 15-12-2016

Table 18. Products

Concentrate containing Ph. Ag and Au g/mol	PbS 239.254	Ag,S 247.804	Au 196.967	lotal
t/a	14 020	65.5	0.190	14 086
t/h	1.753	0.0082	0.0000238	1.761
kmol/h	7.325	0.033	0.000121
%	99 ^34	O 465	n non	100.000
	PI)	Ag	Au	s	lotal
g mol	207.190	107.870	196.967	32.064	233.402
kmol/h	7.325	0.066	0.000121	7.358
t/h	1.518	0.007	0.0000238	0.236	1.761
t/a	12 141	57	0.190	1 887	14 086
%	86.2	0.405	0.0013	13.4	100.0

Iron concentrate g/mol	1 e_:(); 159.692	MnO 70.937	Ahi), 101.961	NiO 74.709	CoO 74.932	Total
%	99.26	0.70	0.01	0.026	0.006	100.00
t/a	155 229	1 100.8	10.9	41.3	10.1	156 330
t/h	19.404	0.13760	0.00136	0.00517	0.00126	19.549
kmol/h	121.506	1.940	0.013	0.069	0.0168
	lc	Mn	Al	Xi	CoO	()	Mass
g/mol	55.847	54.938	26.982	58.710	58.933	15.999
%	69.42	0.55	0.00	0.02	0.01	30.00	100.00
t/a	108 572	852.6	5.7	32.5	7.9	46 921.1	156 330
t/h	13.572	0.1066	0.0007	0.0041	0.0010	5.8651	19.549
kmol/h	243.013	1.940	0.027	0.069	0.0168	366.585

[0096] Certain separated fractions can be utilized after some further treatments (separations or purifications). These include the following.

20165972 prh 15-12-2016

Table 19. Fractions that provide useful products after further separations

Precipitate containing In. Ga and Ge g/mol	111(011).; 165.842	Ga(OII).; 120.742	(;e(OII)₂ 106.605	\l(Ollh 78.00361	Total
t/a	57.775	27.709	8.812	3 307.736	3 402.031
t/h	0.0072	0.0035	0.0011	0.4135	0.425
kmol/h	0.0435	0.0287	0.0103	5.301
%	1.7	n s	n 3	97.2	100.000
	In	(hl	Ge	Al	OH	Total
g/mol	114.820	69.720	72.590	26.9815	17.007
t/a	40.000	16.000	6.000	1 144.148	2 195.883	3 402.031
t/h	0.00500	0.00200	0.00075	0.14302	0.27449	0.4253
kmol/h	0.0435	0.0287	0.0103	5.301	16.1392
%	1.2	0.5	0.2	33.6	64.5	100.0

Precipitate containing As, Sb and Sn g/mol	As,S₅ 310.166	Sb,S₅ 403.820	SnS, 182.818	Total
0/ /0	91.0	7.3	1.7	100.0
t/a	3 279	263	61	3 602
t/h	0.410	0.033	0.008	0.450
kmol/h	1 321	0.081	0.0417
	As	Sb	Sn	S	Total
g mol	74.922	121.75()	118.690	32.064
0/ /0	44.0	4.4	1.1	50.5	100.0
t/a	1 584	158	40	1 820	3 602
t/h	0.198	0.020	0.005	0.228	0.450
kmol/h	2.643	0.163	0.0417	7.097

20165972 prh 15-12-2016

Silver and gold can, in turn be separated from the final waste, by treating it further using conventional techniques.

Industrial Applicability [0097] The present invention provides, among others, an environmentally friendly solution for recycling the zinc-containing waste dust of the steel mills in connection with the recovery of metals from the jarosite precipitate formed as a waste in the zinc mills.

[0098] With the present invention, it is possible to utilize, not only the main components of jarosite (i.e. zinc, iron and lead), but also the critical metals it contains in smaller concentrations (such as silver, gold, indium and gallium)

Citation List

Patent Literature

EP0709472

US3871859

US4385038

Non-Patent Literature

United Nations Environment Programme, (2013), Metals Recycling Full Report Moors & Dijkema, Technological Forecasting & Social Change 73 (2006) 250-265

Rathore & al., Int. J. Civil Engineering & Technology, 5 (2014), Issue 11, pp. 192200

Claims

The claims

1. Process for the hydrometallurgical processing of zinc or steel waste materials selected from jarosite or goatite removers and containing zinc

5 of the arc furnace dust (EAF dust), either individually or in combination, characterized in that the following steps are carried out on one or more waste materials

- alternative sulfuric acid treatment with hot concentrated sulfuric acid,

- a sulfur dioxide (SO2) leaching step consisting of a solid residue and an SO2 solution phase,

10 - sulfidation and flotation of the solid leaching residue to obtain a first fraction of metal sulfides and a first SCL solution which can be recovered;

- addition of hydroxide and subsequent precipitation of metal hydroxides from the combined solution (SO2 solution) and sulphidation and flotation step (first SCU solution)

15 solution phases to form a solid phase and a second SCL solution phase containing the first metal hydroxide fraction which can be recovered,

- addition of sulphide followed by precipitation of the precipitate from the hydroxide solution phase, which also produces a third SCL solution,

- polysulfide treatment of the sulfide precipitate obtained from the polysulfide treatment to provide

20 dissolved sulphides and another metal sulphide fraction which can be recovered,

- sulfuric acid treatment of dissolved sulphides obtained by polysulphide treatment, whereupon the sulphides contained therein are precipitated and can be recovered as the third metal sulphide fraction,

25 - a step of concentrating the solution phase thus obtained to form a salt phase,

- after which a thermal step is performed on the formed salt phase, in which the remaining part of the metals forms a mixture of metal sulfates and metal oxides, and

- finally, a washing step which is carried out on a mixture of sulphates and oxides to give

30 insoluble metal oxide phase and solubilized sulfate phase and may be recovered.

20165972 prh 23 -01- 2020

Process according to one of the preceding claims, characterized in that the sulfuric acid treatment is carried out on zinc-containing electric furnace dust (EAF dust) obtained from the steel industry, whereby the halides transferred to the gas phase are decomposed as hydrides.

A process according to claim 2, characterized in that the sulfuric acid treatment is carried out using concentrated sulfuric acid heated to a temperature of about 200 ° C and mixing this heated acid with a preheated waste material, preferably heated to a temperature of 100-150 ° C.

Process according to any one of the preceding claims, characterized in that the hot concentrated sulfuric acid treated material is mixed with one or more other waste materials, preferably by mixing the sulfuric acid treated dust with jarosite or goethite, or both.

A process according to any one of the preceding claims, characterized in that a leaching step is carried out using SO ₂ , preferably at a temperature of about 90 ° C, whereby a tremendous amount of the metal components of the raw material dissolve and the iron is reduced to its Fe ²⁺ form add raw material (s)

20 solubility of components such as ferrite.

Process according to any one of the preceding claims, characterized in that the solid phase obtained from the SO ₂ leaching step is roasted in order to oxidize the elemental sulfur present in said solid phase.

Process according to any one of the preceding claims, characterized in that a sulphidation and flotation step is performed on the insoluble residue obtained from the leaching step, optionally roasted, by the addition of a sulphidising agent such as sodium sulphide, followed by flotation to obtain product concentrates which

30 contain lead, silver and gold.

Process according to any one of the preceding claims, characterized in that the hydroxide precipitation is carried out on the combined solution phases obtained from the leaching step (SO ₂ solution) and the sulphidation and flotation step (first SCL solution), preferably

20165972 prh 23 -01-2020 using magnesium hydroxide (Mg (0H) ₂ ) as a pH adjusting agent at a temperature between 80 and 90 ° C to separate indium and gallium and germanium from the solution to give a precipitate containing indium , gallium, germanium and aluminum hydroxides.

5

Process according to any one of the preceding claims, characterized in that a sulfide precipitation step is carried out using H ₂ S for another SO ₄ solution and adjusting the pH of the mixture thus formed, preferably using magnesium hydroxide (Mg (O) ₂ ), without significant amounts. iron (Fe ²⁺ ) precipitate, but a sulfide precipitate containing sulfides of arsenic, antimony, tin, copper, cadmium and zinc.

10. The process according to any one of the preceding claims, characterized in that sulphide precipitation is carried out ammoniumpolysulfidikäsittely sulphide precipitate obtained, so that the NH ₄ aqueous solutions of dissolved arsenic (As ₂ S s), antimony sulphide (Sb ₂ S 3) and tin sulfide (SnS) stand out as a precipitate in the remaining copper sulphide (CuS) , cadmium sulphide (CdS) and

15 of zinc sulfide (ZnS).

Process according to any one of the preceding claims, characterized in that the sulfuric acid treatment is carried out on the NH ₄ solution obtained after the polysulfide treatment, whereupon the sulfides of arsenic, antimony and tin are precipitated.

Process according to one of the preceding claims, characterized in that the sulfide solution remaining after the polysulfide and sulfuric acid treatments is recycled.

Process according to any one of the preceding claims, characterized in that

The third SO ₄ solution from the sulphide precipitation is concentrated by evaporation.

Process according to one of the preceding claims, characterized in that the third SO ₄ solution, which is concentrated by evaporation, is subjected to a thermal step in which the iron, manganese, nickel, cobalt and aluminum of the concentrate are converted into their

30, while magnesium remains in the form of sulfate.

Process according to any one of the preceding claims, characterized in that a temperature of 500 to 1200 ° C is used in the thermal step to form solid oxides and separate them from the sulfates remaining in the solution phase.

Process according to claim 14 or 15, characterized in that the remaining thermally treated residue is washed, whereby the insoluble oxide phase forms an iron concentrate (which mainly contains Fe2C3) and the soluble components are transferred.

5, which can be further processed to separate the other components.

Use of a process according to any one of the preceding claims for separating precious metals from industrial zinc-containing dust, which is preferably an arc furnace

10 dust (EAF dust) by first treating the sulfuric acid using hot concentrated sulfuric acid to decompose and sulfate the dust halides and continuing to heat the sulfated dust by heat treatment at a temperature of 400 to 600 ° C whereby the halogens can be removed from the solid fraction.

Use of the process according to any one of claims 1 to 16 for the separation of precious metals from the zinc or goitite residue of the zinc industry by directly feeding the residue to the sulfur dioxide (SO2) leaching step and continuing the process of claims 1 to 16 in the following steps.

Use according to claim 18, wherein the zinc industry residue is a jarosite residue and the solid phase obtained from the SCE leaching step is roasted to oxidize the elemental sulfur present in said solid phase.