LU83997A1 - PROCESS AND APPARATUS FOR THE RECOVERY AND CONCENTRATION OF NON-FERROUS MATERIALS SUCH AS ZINC AND LEAD - Google Patents

Description

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......... 0 ~ / 'Τγ'ΊΤΙ "^ RAND-DUCHÉ DE LUXEMBOURG

Patent N * ...... Q- O-d ..... O / du 1Q. March ... lêS2t ..................... Monsieur the Minister of Economy and the Middle Classes

Title issued ......................................... Intellectual Property Service

—— LUXEMBOURG

Patent Application I. Application ..JiüU ^ iU ^ ßäMmJSQCmDA '_ .. AZIOMBIA ΚΙΜΕ0-ΙΖΤΜ, ΏνΒ8Ι (& / β ^^ ________________________________ (l). ZÙœ ... K .. JAattei .... ly .1iome.y .... Italy ......................................... .......................................... ........ .................................................. .............

represented by, E.Meyer8 & E.Freylingert ..... Ingf aonsejls en propr.inâ.M .................. (2) .A6 .... .ruei ... d ^ .JSimeiiÂrey ... Li ^ mtmirg, ........ iegiMmt..en ^ i ^ al £ i ^ de-MmâaÈaàæes ............ .................

deposit) this. „Ma. Mi ^ .Jsdl.rte3if ^ sxd ^ qu £ àxA ... vdngi deux -......... — ...................... ........ (3) 'at JE0? ..______________ hours, at the Ministry of the Economy and the Middle Classes, in Luxembourg: 1. this request for obtaining a patent for invention : .J! Erϋoëäê..et .... ^^ pcœâ ^ L · pΩllP ^ JΛ.r {ruΌér.atian ... et ... la..aonΰentrxtian .... de .. ~ .... ....................... (4) non-ferrous materials such as zinc and lead "............. .................................................. ............

2. the delegation of power, dated .......... F.oxs ............................ ................. February 15, 1982____________ 3. description in language ....................... .................. of the invention in two copies; 4. ..... Mne ............... drawing boards, in two copies; 5. the receipt of the taxes paid to the Luxembourg Registration Office on .....: ........................... .................................................. ..........

declares (s) assuming responsibility for this declaration, that the inventor (s) is (are): Æmluigi.MéÂLïILIâs ...... YiM ^ .S £ nmx: .A5y ^ cmy ... Ii2 lie ................................................ .................................. (5) claim) for the above patent application the priority of a (s) request (s) from (6) l? rev ^ t .................................. ............................ registered in (7) Italy ............. .................................................. .....................................

le ........... tr.eize .... mar.s .... ml ... neuf ..... Qent .... qîiaire .... r.ingt. ..wi ............................................... .................................................. ...... (8), „.................. s.Qm ... le..MQ ... 2QMÂ..A / 3.1 .. .................................................. .................................................. .................................................. ......................................

in the name of ...... td, .. ââp.QeOBt.e ............................... .................................................. .................................................. .................................................. ............. (9) elect (elect) for him / her and, if appointed, for his / her proxy, in Luxembourg .............. ......................

.................................................. .................................................. .................................................. ... (10) requests (nt) the grant of a patent for the invention for the subject described and represented in the abovementioned appendices, - with postponement of this grant to ......... six .. ....................................... months. (11) T, km of ^ anâaiaires__ Ç ^ IL Deposit Report

The above patent application has been filed with the Ministry of the Economy and the Middle Classes, Intellectual Property Service in Luxembourg, on: / F>% \ t / £ f s? '’” ···. % \ Pr. The Minister p 15 bwirps la / L. a- = * of the Economy and the Middle Classes, ................................ I s $ ·. Ä / / ma BS007 en

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yEL-3272 / EM / BM

Claiming priority of a patent application filed in Italy on March 13, 1981 under No. 20343 A / 81

PATENT

Process and apparatus for the recovery and concentration of non-ferrous materials such as zinc and lead f i I SAMIM SOCJETA 'AZIONARIA KINERO- 1 KETALLDRGICA S.p.A.

! P.le Mattei 1 | I - Rome i 4! / t- 4

Method and apparatus for the recovery and concentration of non-ferrous materials such as zinc and lead.

The present invention relates to a process for enriching, in useful non-ferrous metals, such as lead and zinc, by volatilization or fumigation, at a suitable temperature, of products which contain such metals, in a variable percentage, in the form of oxides or sulfides of said metals, and the apparatus for carrying out said process is another aspect of this Invention.

The products to be used can be either primary raw materials (ores) or secondary raw materials (steelworks fumes, mineral residues and metallurgical slag).

The currently most important processes in the volatilization field for recovering, or concentrating, non-ferrous metals such as zinc and lead will be described below.

Process with the Waelz furnace: in this process, the charge, which contains zinc (at most 30 to 35/0, lead, and other metals (in a smaller proportion) is mixed with dust of coke or anthracite dust in a proportion of 18 to 25 $ by weight, and is loaded in a conventional rotary oven inclined from 2 to 4 ° relative to the horizontal.

An appreciable amount of useful metals is thus recovered. The main drawbacks are the considerable volume of the installations, with very large exchange surfaces between the volumes to be treated and atmospheric air, so that the useful heat can be recovered only 50%.

The cyclone furnace process is a process in which the charge, mixed with the coke dust, is sent to a cylindrical cyclone furnace where it is brought into tangential contact with the preheated air. The fumigation is carried out in an adjacent oven, which is generally an electric arc oven. In the electric furnace non-volatile materials can be collected in a white phase which is separated from the slag. So, energy consumption con- X? 2 sldérables are involved. In addition, the load must be completely dried and must have a maximum granulation of one millimeter. It has now been surprisingly verified that the disadvantages of conventional technology can be eliminated by working in a single reaction zone in a medium with a partially oxidizing and partially reducing nature.

or

In addition, using the process suggested here, it is possible to use high quality reindeer and small charcoal instead of natural gas or coke. These advantages do not prevent the obtaining of a satisfactory mode of heat distribution as well as the establishment of suitable physicochemical conditions for the development of the reactions of interest.

A first object of the invention is a process which provides the mixing of the products containing Pb and Zn in the form of their oxides or their salts (sulfates, sulfides, silicates, aluminates and others) with a product containing carbon, the combustion partial carbon giving carbon monoxide (CO).

The process is carried out so as to have two stages.

The first stage is a direct reduction of zinc, starting from its oxides or its salts, with volatilization of the zinc and the lead oxide contained in the starting charge. Said reduction takes place at the expense of the carbon which is contained in the carbon product used.

The second stage is a gas phase oxidation of the zinc produced in the first stage, by air and / or oxygen, which is carried out concurrently with the zinc vapors * -.Jst. ’Trained.

The non-volatile fraction of the charge, which is essentially composed of CaO, S10 ^, and FeO, that is to say, in the form of oxides, and which contributes to forming the slag, will have its concentrations in various elements selected so as to produce a slag at a melting temperature not exceeding 35 Pas 1200 ° C, so that the non-volatile materials can leave the reactor in the liquid phase.

For the latter reason, it will be necessary. to provide appropriate additions to the basic products if the concentrations of the components are not sufficient.

J

to meet the conditions specified above.

During the course of the first stage, under determined and imposed processing conditions, metallic lead can be obtained by the reaction: 5 PbO + CO -> Pb (liquid) + CO ^

The metallic lead thus obtained will mix with the slag but will be separated by gravity. The carbon monoxide collected around the axis of rotation causes the volatilized products upwards and is burnt with oxygen so that additional heat can be supplied to the process. Processing temperatures range from 1100 to 1600 ° C.

A second object of the invention is the apparatus for carrying out the process in question.

Reference is made to FIGS. 1 and 2 of plate 15 cl-Jolnte.

The reactor has a frustoconical shape and is composed of one or more frustoconical parts, which are optionally replaced by their external or internal enveloping curved surface, and is arranged with its vertical geometric axis 20 and can be rotated around said axis 1. The reactor consists of a metal casing 2, which is internally lined with a refractory layer 3.

The angular speed of rotation and the angle between the generatrices of the internal surfaces of the walls of the frustoconical bodies (or their enveloping surfaces as may be the case) and the vertical, are such that the charged solid phase remains, from a dynamic point of view, in equilibrium under the concurrent actions of weight, rotational inertia forces and friction forces due to the internal walls, while the liquid phase formed during the treatment flows towards the base of the reactor which has a drain hole 5.

The inside diameter of the largest base of the reactor can be from 1 to 10 meters long and preferably, Q, from 2/6 meters, while the inside diameter of the smallest base varies between 0.2 and 1 metre. The diameter of the drainage hole must be between 5 and 30 $ of the diameter of the largest base depending on the potential production of the installation, and can even reach 100% of the diameter of the smallest base. The angle of the generators with the vertical • • * can vary between 10 and 60 °, we prefer the values if greater than? 0 °.

The speed of rotation of the conical body should be between 10 and 80 rpm.

(In the case of a device composed of more than one truncated cone, or of a curved surface enveloping the generatrices of the cone or their tangents, the angle between the consecutive truncated trunks must not exceed 30 °).

10 In addition, there are from 2 to I) pipes (nozzles) 6 and 7, with their end opening inside the reactor and suitably inclined, the two nozzles being capable of being displaced along the vertical axis so as to that they can be used both for the loading of the weakened charge and that of the fuel.

On the other hand, one or more pipes 8, (a maximum of four), are essentially parallel to the generatrices of the internal surface and have perforations 9 over their entire length or almost, the said perforations being regularly spaced if desired, and the air and / or oxygen are continuously blown and possibly preheated.

The speed of the combustion auxiliary current has a radial centrifugal component and a tengential component with respect to the path of the point of impact on the wall, which agrees with the movement so as not to interfere with the dynamic conditions. of the charge which is present either in the liquid J state or in the solid state,% _ Finally, a central pipe 10 is provided / ^. s for the injection of the combustion auxiliary current to a word ^ of addition ^ O both to burn the oxide / carbon which has formed and to cause the oxidation of the Zn vapors.

The feedstock can be a primary raw material (an ore) and / or a secondary raw material (steelworks fumes, residual treatment sludge and others) • 35 which contain lead and zinc, in variable proportions, such as 1 % and more. The granulation will be between 0.01 mm and 5 mm. The products can be introduced at the top of the reactor after having already been mixed with the fuel, the latter also being of the fine-grain type, or else they can be supplied separately by the aforementioned pipes so as to obtain a sufficient release of heat, in accordance with at the desired temperatures, and also to provide a reducing medium at the top.

5 In the bottom of the furnace, by the pipes not yet used up to this stage, products containing carbon are added to ensure the treatment conditions (reduction) and the thermal conditions, necessary.

The amount of carbon to be used is a function of the amount of zinc and varies from 8 to 25 Æ of the charge and preferably from 15 to 20 $.

As combustion aid, air is used, possibly preheated to 600 ° C and enriched with oxygen, or also pure oxygen, possibly preheated to 200 ° C.

It should be remembered that the speed of the process is very high because of the very large contact surface between the individual phases, which is a direct consequence of the fine granulation of the loaded product and the rotary movement of the reactor. The consumptions which can be predicted are almost stoichiometric.

The present invention is illustrated by the descriptive and nonlimiting example below.

EXAMPLE

The raw material is steelmaking smoke 25 containing $ 20 of zinc and $ 5.5 of lead. The reactor is a throne-like receptacle flared downward and composed of a metal sheet envelope lined internally with a refractory lining, the dimensional specifications being as follows: 5 ° Diameter of the largest base of the cone (upper section) 5800 mm

Diameter of the smallest supper base (lower section) 800 mm

Height of the truncated cone 5000 mm "55 Angles of the generators of the cone with the vertical 45 ° and 10 °, respectively (top and bottom).

AT

6 * The characteristic parameters of the treatment are as follows:

Cone rotation speed 20 ^ pm Oxygen flow 5 normal per min 5 Supply speed for the cone; kg per min

Load feed speed: 65 kg per min

The charge is mixed with 0.10 kg of coke per kg of charge, the coke being intended to be used as auxiliary coke.

Under these conditions, an oxide is obtained containing $ 60 of Zn and $ 10 of Pb, with a production of 20 kg per minute and yields of Zn and Pb of the order of $ 93-95 and ^ j ^ more.

i have

Claims (5)

1. Poup / i'écupératlon process or the concentration of Zn v 't Pb from primary or secondary raw materials j comprising mixing the product with carbon, partial combustion ^ ^ tlon carbon to obtain CO, characterized by fact that it is carried out in two stages, (in the first stage 11 there is a direct reduction of zinc by reaction with the carbon contained in the carbonaceous compounds and the volatilization of both zinc and lead oxide, the tempé-10 necessary erasures being reached by partially burning carbon and CO with air and / or oxygen, the products - which contain zinc and lead having the appropriate granulation; in the second stage an oxidation occurs * in the gas phase of the zinc obtained in the first stage, by means of air and / or oxygen. 2. Method according to claim 1, characterized in that the temperatures vary from 1100 ° C to 1600 ° C. d. Process according to Claims 1 and 2, characterized in that the granulation of the solid products of the charge is between 0.01 mm and 5 mm. 4. Method according to any one of claims 1 to d, characterized in that the combustion auxiliary, air and / or oxygen, is preheated to a temperature between 200 and 600 ° C. 5. Apparatus for carrying out the process according to claim 1, characterized in that it is frustoconical and "" is composed of one or more truncated trunks optionally replaced by their respective enveloping surfaces, Internal or external, the reactor being composed of '' an enve-50 metal loppe (2) internally lined with refractory products (d) and able to rotate around its geometric axis (1) arranged vertically, a drain hole (5) being formed in the bottom of the reactor so that the charged solid products, under the effect of the various forces, adhere to the internal walls of the reactor and so that the liquid substances formed can flow towards said flow hole (5), the internal diameter of the largest base of the ^ cone being chosen between 1 and 10 meters, the inside diameter "8 of the smallest base being 0.0 to 1 meter, the diameter of the drain hole (5) being 5 to 100 $ of the inside diameter of the smaller base of the cone, the angle (4) of the generators of the cone with the vertical being between 10 and 60 °, and the speed of rotation of the reactor between 10 and 80 revolutions per minute. 6. Apparatus according to claim 5, characterized in that the generatrices of the conical surfaces must not have relative to each other an inclination greater than "50 °. ---- ^ * · * i L [I