AU601019B2

AU601019B2 - Method of processing lead-containing sulphide materials

Info

Publication number: AU601019B2
Application number: AU11628/88A
Authority: AU
Inventors: Jury Alexandrovich Grinin; Efim Lazarevich Kremerman; Vyacheslav Alexandrovich Lysenko; Ivan Petrovich Polyakov; Gulnar Asylbekovna Sabitova; Jury Ivanovich Sakov; Jury Ivanovich Sannikov; Anatoly Petrovich Sychev
Original assignee: VNI GORNO METALL INSTI
Current assignee: Vsesojuzny Nauchno-Issledovatelsky Gorno-Metallurgichesky Institut Tsvetnykh Metallov (vniitsvetmet)
Priority date: 1988-02-16
Filing date: 1988-02-11
Publication date: 1990-08-30
Anticipated expiration: 2008-02-11
Also published as: FR2628119A1; FR2628119B1; AU1162888A; DE3804809C1

Description

-LP I w .L S F lef:0 344 FORM COMMONWEALTH OF AUSTRALIA PATENTS ACT 1952 COMPLETE SPECIFICATION

(ORIGINAL)

FOR OFFICE USE: Class Int Class Complete Specification Lodged: Accepted: Published: Priority: This document contains the amendnments made under Se tion 49 ar d is correct for printing.

Related Art: Name and Address of Applicant: Gorno-Metallurgi chesky Address for Service: Vsesojuzny Nauchno-Issledovatelsky Institut Tsvetnykh Metallov (Vniitsvetmet) USSR, Ust-Kamenogorsk ulitsa Promyshlennaya, I UNION OF SOVIET SOC. REPUBLICS Spruson Ferguson, Patent Attorneys Level 33 St Martins Tower, 31 Market Street Sydney, New South Wales, 2000, Australia Complete Specification for the inventior entitled: Method of Processing Lead-Containing Sulphide Materials The following statement is a full description of this inventiun, including the best method of performing it known to me/us 5845/3 METHOD OF PROCESSING LEAD-CONTAINING SULPHIDE

MATERIALS

The present invention relates to non-ferrous m tallurgy and more particularly to methods of processing lead-containing sulphide materials.

The present invention can be successfully used for processing plymetallic sulphide ores and concentrates containing non-ferrous, trace, rare, and noble metals.

0 q9 0 CO The main trend in improving pyrometallurgical produc- 0 o0013o 10 tion of heavy non-ferrous metals consists in developing the 0 extraction methods based on autogenic melting of sulphidle materials. The advantages of autogenic processes include a 0 V,9 high specific output, a sharp decrease of the volume of technological gases, heating capacity of concentrates which 0 00 15 decreases considerably the use of external heat sources, a possibility of the effective processing of a material relatively depleted in non-ferrous metals.

9 0 Different versions of autogenic processes are known: all of them are characterized by the use of a highly developed surface of the sulphide material for ensuring the autogenic nature of annealing and melting processes.

Known in the art is a method of processing lead-containing sulphide materials (SU, A, 851981) by melting a mixture of lead-containing sulphide materials, fluxes, and return dusts, in a flame of an oxygen-containing gas, the melting being accompanied by introduction of a ground carbon-containing reducer into a flame and by a transfer of metals coni 2 tained in the mixture into the melt in the form of oxides with liberation of gases containing return dusts, reduction of metal oxides in the dispersed melt by their filtration the layer of a solid carbon-containing reducer with the formation of lead and lead-depleted slag, and separation of lead from the slag.

However, according to the known method, a refractory ash formed on the surface of particles of the solid carbon- 0 containing reducer is slowly dissolved in an oxidized melt o. 10 due to a low velocity of the motion of dispersed melt drops with respect to the reducer particles. Therefore, an ash o 0° layer is retained on the surface of the particles thereby hindering the contact of the lead-containing melt with car- 0o0 bon which decreases the output of the processing and deter- .00 15 iorates the quality of lead being prepared.

In addition, in the flame of the oxygen-containing gas (for instance, oxygen) the partial oxidation of the solid carbon-containing reducer with oxygen takes place. This favours the formation of leady matte and enhances the lead 20 content in slags which in its turn decreases the extraction of lead and increases the losses thereof in the course of subsequent processing matte and slag.

It i a an1 objfct eof th invontion *to pro.-o-n'^ mte^_hd of processing lead-containing sulphide mate wherein the reduction of metal oxide e dispersed melt by their filtration thr e layer of a solid carbon-containing 'd ia Barformd in a way enhanin 1-the output of the- L n ii L l r 3 It is the object of the present invention to overcome or substantially ameliorate the above disadvantages.

There is disclosed herein a method of processing lead-containing sulphide materials by melting a mixture of lead-containing sulphide materials, fluxes,- and return dusts in the flame of an oxygen-containing gas, the melting being accompanied by introduction of a ground carbon-containing reducer into a flame and by a transfer of metals contained in the mixture into the dispersed melt in the form of oxides with liberation of gases containing return dusts, reduction of metal oxides in the dispersed melt by filtration of the melt through the layer of a solid carbon-containing reducer with the formation of lead and lead-depleted slag, and separation of lead from the slag; wherein the reduction of metal I oxides in the dispersed melt is performed under bubbling a gas inert to the composition of the slag through the lead-depleted slag.

It is expedient in a method of processing lead-containing sulphide material to use a gas inert to the composition of the melt in amounts equal to 5-22% of the amount of the oxygen-containing gas.

It is desirable in a method of processing lead-containing sulphide materials to use return dusts simultaneously with the gas inert to the 20 composition of the melt, It is also desirable in a method of processing lead-containing sulphide materials to use nitrogen or carbon dioxide as a gas inert to the composition of the melt,

KLI

-4- Sometimes it is expedient in a t.hod of processing lead-containing sulphide materials to use gases liberatinin the cour.,se of melting as a gas inert to the composition 1 of the melt.

It is preferable in a method of processing lead-containing sulphide materials to pre-heat the gas inert to the composition of the melt to temperatures exceeding 200 0

C.

It is reasonable in a method of processing lead-containing sulphide materials to use clinker of rolling zinc-contamning materials as a solid carbon-containing reducer.

It is also reasonable in a method of processing leadcontaining sulphide materials to use clinker of rolling zinccontaining materials in amount 8-25% of the mass of leadcontaining sulphide materials.

The present invention ensures an increase in the velocity of motion of par.ticles of a solid carbon-containing reducer with respect to the melt which enhances the rate of dissolution of refrectory ash in the melt and improves the onditions of contact between the lead-containing melt and 120 carbon; as a result, the output of the melting process rises and the amount of lead obtained grows.

Besides, the present invention make it possible to eliinate oxidation of a solid carbon-containing reducer with oxygen of a. gas phase due to the fact that the surface of carbon particles is coated with slagged non-ore minerals as a result of which the reducing abilities of the solid carboncontaining reducer improve and the amount of lead increases.

The present invention also ensures a predominant of oxidation of sulphides as a result of which the metals enter the flame zone nearest to the reducer in an oxidized form which eliminates the formation of leady matte and also increases the amount of lead prepared.

A method of processing lead-containing sulphide materials resides in that a mixture of lead-containing sulphide materials, fluxes, and return dusts is melted in a flame of an oxygen-containing gas, to this end, a solid carbon-contai- V'L' Nze_ ning reducer "Isimultaneously fed into a flame, the melting being accompanied with a transfer of metals contained in the mixture into the dispersed melt in the form of oxides with liberation of gases containing return dusts. Then the reduction is performed in the dispersed melt of metal oxides by filtration of the melt through a layer of solid carboncontaining reducer under bubbling through the layer of the reduced the melt of a gas inert to the compoeitJon of this melt with the separation of lead from lead-depleted slag.

The accomplishment of the reduction of metal oxides (first of all, lead oxide) under bubbling a gas inert to the melt composition through the melt enhances considerably the dissolution rate of refractory ash formed on the surface of carbon-containing material. As a result no ash layer is formed on the surface of the reducer particles and the contact between metal oxides and carbon becomes much better. This increases the output of the process and favours a more compl.ete extraction of lead.

44, 2) 1 15 a OttieFIR WO awa we lie aWLLvan.L. lJJ ILv r inert to the metal composition used for bubbling through the i1 I 6melt is 5-22% of the total amount of the consumed oxygen- Icontaining gas. If the amount of gas used for bubbling is less than 5% of the total amount of the oxygen-containing gas, the resistance forces of the viscous melt cannot be overcome properly and, correspondingly, the required velocity of motion of the reducer particles with respect to the melt is not ensured. This decreases the output of the process and the extraction of lead. The use of the gas for bubbling in amount more than 22% of the total amount of the oxygen-containing gas is undesirable since a high intensity of bubbling leads to the formation of "windows" in the layer of the carbon-containing reducer as a result of which the reducing ability of the reducer decreases and, hence, the output of the process and lead extraction also decrease.

Aooordin to the herein d m return dusts are fed simultaneously with a gas inert to the composition of the melt.

A The use of nitrogen or cabron dioxide is most preferable according to the present invention.

Sometimes it is technologically favourable to use gases liberating in the course of melting as a gas inert to the composition of the melt.

Ao to to pro nt inven+er, he gas used for bubbling through the melt must be heated to temperatures no less than 200°C. When the gas delivered for bubbling or a mixture thereof with return dusts is preliminary heated, a temperature of the melt being reduced rises which results in the acceleration of the reduction processes and favours the accomplishment of the object of the invention. Heating i r ir i I u ,I r;-L;c -7 of the gas for bubbling to temperatures below 200 0 C does not ensure the required heat balance of the reduction since the reduction process is endothermal; this decreases the output of the process and the extraction of lead.

Azl.ding t tho pro ont inv ntion, clinker of rolling zinc-containing materials is used as a solid carbon-containing reducer in amount 8-25% of the mass of lead-containing sulphide materials.

o o Clinker of rolling zinc-containing materials contains, o 10 along with valuable components (non-ferrous metals), elemental iron and carbon whose particles are coated with a slag layer from non-ore minerals. Due to this fact no oxidation of carbon takes place in an oxygen flame and, hence, the reducing ability thereof is utilized more completely. In addition, the oxygen-containing gas is used for its designated purpose, i.e. for oxidation of metal sulphides to metal oxi- WS des. It should also be taken into account than elemental iron is a good reducer of melted oxides of non-ferrous metals ,su* (lead) as a result of which they are reduced more completely.

20 The amount of clinker is dictated by the necessity to ensure the conditions of a complete reduction of lead oxide.

Clinker of rolling zinc-containing materials is used in amount equal to 8-25% of the mass of lead-containing sulphide materials.

-@Wclinder is supplied in amount less than 8% of the mass of sulphide materials, the reduction of lead oxide is incomplete; when the amount of clinker exceeds 25% of the mass of sulphide materials, the yield of slag becomes so u igh (because of the slag-forming components in the clinker) that the absolute losses of lead with the slaggrw For a better understanding of the present invention specific examples of realizing thereof are given hereinbelow by way of illustration.

Example 1 A mixture of lead-containing sulphide concentrate and fluxes of the following composition (mass lead 48.1, zinc copper 1.82, iron 5.86, sulphur 16.48, silicon dioxide 6.55, and calcium oxide 4.65, was processed.

The return dusts obtained in the processing were added to the mixture and coke was used as a solid carbon-containing reducer. The melting was performed in the flame of comnmercial oxygen taken in amount 214 nit 3 per ton of a mixture of concentrate and fluxes. The above metals contained in the mixture passed into the melt in the form of oxides and the gases formed in the course of me~lting and containing return dusts were liberated. Then the metal oxides were reduced with coke under bubbling nitrogen through the melt, the nitrogen being used in amount 3,5, 12, 22, and 25% of the amount of commercial oxygen supplied for melting 11, 26, 43, 47, and 54 nm 3 respectively, per ton of a mixture of concentrates and fluxes). I~n the course of reduction lead and lead-depleted slag were prepared.

The r'esults of the experiments are given i-n Table 1.

For the sake of comparison Table 1 lists also the data of the experiments conducted when nitrogen was fed in amount -9less (3 and more (25 than claimed limits of the amount of oxygen.

Example 2 The sulphide concentrate considered in Example 1 was processed under similar conditions. Nitrogen and return dusts were supplied for bubbling.

The results are given in Table 1.

SExample 3 The sulphide concentrate considered in Example 1 was I 10 processed under similar conditions. Carbon dioxide instead i of nitrope was fed for bubbling.

The -asults are given in Table 1.

jExample 4 The sulphide concentrate considered in Example 1 was processed under similar conditions. The gases liberated in the course of melting were used for bubbling.

The results are given in Table 1.

Example The sulphide concentrate considered in Example 1 was processed under similar conditions. Nitrogen was heated to 150, 200, 300, and 350°C. Consumption of nitrogen was 12% of the amount of commercial oxygen.

The results are given in Table 2.

.il i 1- 10 The effect of stirring the melt being reduced on the output of the process an Nos Parameters The proposed method with the supply of gas into the melt: Commercial nitrogen (carbon dioxide) Consumption of nitrogen (carbon dioxide) of the amount of oxygen fed for melting ,I Table 1 id extraction of lead Consumption of gas 12% of the amount of commercial oxygen per melting 3 5 12 22 25 Melting Nitrogen gases in a mixtu with retur dusts 1 Output with respect to concentrate, kg/h, nitrogen 1250 1280 1300 1320 1250 1320 1340 2 carbon dioxide 1250 1280 1300 1320 1250 3 Output with respect to metallic lead, kg/h, nitrogen 531 555 578 574 529 588 598 4 carbon dioxide 531 555 578 574 529 Extraction of lead, mass nitrogen 88.3 90.1 92.5 90.4 88.0 92.6 92.7 6 carbon dioxide 88.3 90.1 92.5 90.4 88.0 re n

H

0 !i I 11 Table 2 The effect of gas temperature on the output of the process and extraction of lead

I

j i 6Q Nos Gas tempera- Output with Output with Extraction ture, oC respect to respect to of lead, concentrate, lead, mass kg/h kg/h 1 150 1220 518 88.3 2 200 1360 601 91.9 3 300 1385 616 92.5 4 350 1410 631 93.1 As i seen from examples 1, 3 (Table the consumption of gas for bubbling in amount 5-22% of the consumption of oxygon-containing gas for melting increases the output of the melting process whereas the consumption of more than 22% causes a decrease of the output and lead extraction.

The observations have shown that an enhanced consumption of the gas for bubbling favours the formation of "windows" in the layer of carbon-containing reducer and makes the reducer less efficient.

Examples 2, 4 show that the use of nitrogen with return dusts and susted gases for bubbling in the course of melting ensures the high output of the process and high extraction of lead into metal.

Example 5 illustrates that the use of "cold" gas for bubbling (at a temperature below 2006C) decreases the rate of reduction of lead oxide and, correspondingly, lowers the 12 output of the process and extraction of lead.

Example 6 SThe sulphide concentrate considered in Example 1 was S processed under similar conditions but instead of coke clinker of the following composition was fed for the reduction (in mass copper 2,5, zinc 2.3, lead 0.8, sulphur iron 30.1, silicon dioxide 12.6, calcium oxide 2.8, carbon i 20.8; the amount of clinder was 6, 8, 15, 25 and 30% of the amount of the sulphide concentrates. Nitrogen was supplied for bubbling in amount 12% of the amount of commercial oxygen. The results of the experiments aie given in Table 3.

As is seen, the use of clinker as a solid carbon-containing reducer in the course of melting lead-containing sulphide raw material in the flame of an oxygen-containing gas ensures first of all the predominant oxidation process without oxidation of carbon and then the reduction process with a high output of the whole process and high lead extraction.

The present invention makes it possible to improve t,.

conditions of contact between a lead-containing melt and j carbon thereby increasing the output of the melting process iJ and the amount of lead.

I I i 1 ILisi~uYI~-- Table 3 The- effect of clinker COnS~Unption on extraction of lead Conslimp- The yield of Lead content Extarac- Losses of tion of melting to in melting tion of lead with clinker, ve i th t o f products, lead, $leg, 7o of the sulphide mas S% mass 70 mass weight concentof SUlphi- rate, de con- mass 0% ce ntrate black slag _Iead slag lead 45.3 26.2 98.31 3.B9 45-7 28.2 98.04 1.49 46.6 30.5 97.3 1.15 92.6 93. 1 94.1 931.3 92.4 2.13 0.88 0.73 0.89 1.15 46.8 38.4 96.05 1.12 46.4 52.9 95.71 1.04 0 9 54 t 44

Claims

2. A method as claimed in claim I, wherein the gas inert to the composition of the lead-depleted slag is used in an amount of 5 to 22% of the amount of the oxygen-containing gas.
3. A method as claimed in claim 2, wherein return dusts are fed simultaneously with the gas inert to the composition of the slag.
4. A method as claimed in claim 2, wherein nitrogen or carbon dioxide is used as a gas inert to the composition of the slag. A method as claimed in claim 1, whereirn gases liberate in the course of melting are used as a gas inert to the composition of the slag.
6. A method as claimed in any one of claims 3 to 5 wherein the gas inert to the composition of the slag is preliminarily heated to a temperature exceeding 200 0 C.
7. A method as claimed in claim 1, wherein clinker of rolling zinc-containing materials is used as a solid carbon-containing material.
8. A method as claimed in claim 7, wherein the clinker of rolling zinc-containing materials is used in amount of 8 to 25% of the mass of lead-containing materials.
9. A method of processing lead-containing sulphide materials, the method being substantially as hereinbefore described with reference to any one of the Examples with the exception of any comparative examples. SLN/24761 DATED this THIRTEENTH day of JUNE 1990 Vsesojuzny Nauchno-Issledovateisky Gorno-Metallurgichesky Institut Tsvetnykh Metallov (Vniitsvetmet) Patent Attorneys for the Applicant SPRUSON FERGUSON 24761