DE377143C - Process for the extraction of metals from composite ores - Google Patents

Description

Process for the extraction of metals from composite ores. object the invention is a process, separately and in successive stages Metals to be won from confused ores, such as B. Static ores, which contain zinc, copper, lead, silver and gold.

It is known to extract lead from lead zinc sulphide ores in the manner that the lead is converted into sulfate, which is dissolved by a chloride solution is brought - and that the lye freed from the lead is used again.

However, this known method is only about treatment of lead zinc sulphide ores, in which the conditions are completely different than when complex ores are to be treated.

One of the main reasons why so far complex ores are made of metals have practically not been extracted by a hydrometallurgical process, is -that the different metals also have different solvents and precipitants require, and these must be applied in such a way that the metals concerned can be recovered without the extraction of other metals in the ore thereby is affected.

It is well known that copper and zinc are replaced by sulfuric acid and gold and silver can be extracted by potassium cyanide; but so far the technology had Not yet a usable process to dissolve lead as sulphate with a chloride liquor.

In the known process - the lead sulphide is converted into lead sulphate by means of sulfuric acid or an acid sulphate. But at the same time also all or more of the metals contained in the sulphide ores, such as zinc, copper, Silver and gold, converted into sulfate, and this conversion into sulfates must be disadvantageous be- for the subsequent extraction of such other metals in a pure state.

For this reason, the present process does not produce sulfuric acid or an acid sulphate is used, but the ore is roasted and only afterwards with Sulfuric acid leached to remove the copper and zinc; after these two are removed, Chloridlatige is added to lead chloride and silver chloride in Form solution. From this solution lead and silver are made according to the well-known Cementation process precipitated, and to the residue after removal of the lead and silver is given potassium cyanide to extract the gold.

Through extensive experimentation, the inventor has found that fresh chloride liquor dissolves lead sulfate fairly easily. However, as soon as the chloride liquor contains about 0.5 percent lead, it is so saturated with lead that it brings practically no further lead sulfate into solution.

One of the main characteristics of the present invention is that the lead dissolved by the chloride liquor from lead sulfate is constantly from the Solution is removed during the dissolution process to the extent that the lead is removed from the solution is absorbed. As a result, the liquor can never be saturated or their releasing effect lose, rather it retains its ability to dissolve new amounts of lead sulphate.

The method is to be described in more detail below.

The ore is crushed to a mesh size of about 5oo meshes to t qcm (Oo meshes to I inch) and roasted to remove the metal sulfides of the ore in transferring soluble form. Copper and zinc are made soluble in diluted ones Sulfuric acid, lead and silver in a solution of sodium chloride or iron chloride, Gold in a solution of zinc.

The successive stages in the process are as follows: crushing, Roasting, leaching with sulfuric acid to extract copper and zinc in solution, Electrolysis of the purified solution to obtain electrolyte zinc and copper (if the ore contains enough copper to be electrolytically precipitated) if not (the copper is precipitated from iron or zinc. Filtered by pressing, Washing out the residues after the copper and zinc; leaching. Leaching of the residues with a chloride solution (or solutions) to dissolve lead and silver. Knock down of lead and silver from solution on iron or in any other suitable Way, x_. B. on anything higher than lead in the electrical series (more electropositive) metal; filter by pressing and washing after recovery of lead; Leaching of the residues with potassium cyanide: filtering by pressing and Washing out the 'residues after extraction of the gold, then clearing away the residues.

Experiencing the '' can be done in the following ways:? After (iah ore suitable, about up to a sieve size of 500 meshes per square centimeter, crushed it is roasted with a cold, weak solution of sulfuric acid stirred, the clear solution is drawn off and purified, the residue is filtered, the filtrate is purified and electrolyzed to make electrolyte zinc and sulfuric acid to obtain which the latter is used again for leaching fresh ore.

This process runs in a circuit from the zinc liquor vats through the cleaner and electrolytic cells back to the zinc lye vessels.

i If copper is present in sufficient quantity, it becomes electrolytic like to a point where the solutions present about 0.75 percent copper of zinc sulfate; the rest of the copper is precipitated on iron or zinc dust.

The precipitated copper can either be fused or roasted occluded, redissolved in sulfuric acid and electrolytically precipitated.

The residues containing the lead are first agitated in hot sodium chloride solution in suitable stirring and thickening devices. The following reaction occurs: Pb S04 -1- 2NaCl ----. PbClz 1- Na. » S04. Before the solution has become saturated with lead chloride, the clear lead chloride solutions are continuously drawn off from the thickeners, and the lead is deposited on iron (or a metal with a higher electrical voltage than lead) - preferably in the form of metal dust - which The solution is regenerated or returned to the stirrers so that the saturation point of the chloride solution for lead is never reached, and the solvent is regenerated without ever losing its effectiveness - Pb -j- Fe C12 -4- Na. SO4 So the caustic liquid contains both iron chloride and sodium chloride, and the following reactions apply: PbS04 -f- 2 NaC1 -E- FeC12 -j- Na2S04 = Pb CL + 2 Na .S04 + Fe C12 or PbS04 -f- FeC12 -f- 2 NaCI + Na2SO4 Pb C12 + Fe S04 -j- Na2SO4 --f- 2 Na Cl. The amount of iron chlorine in the solution increases continuously until it becomes sufficiently effective to dissolve the lead sulfate n; then no more sodium chloride needs to be used, according to the following reaction: Pb S 04 --f - Fe C12 - Pb C12 + F e S 0,;.

At the same time, the iron chloride is reformed from the ferrous sulfate with the precipitation of lead by iron: PbC12 -f- FeS04 -f- Fe --- Pb -} - FeCI = -j- FeS04. If this solution is used continuously for leaching lead sulphate containing ore, the content of ferrous sulfate in the solution increases. If the When the saturation point is reached in the solution, ferrous sulfate can crystallize out and recovered as a by-product, or part of the solution can be discharged, to reduce the effectiveness of the solvent by the ferrous sulfate impede. The loss of chlorides as a result of the removal of part of the iron chloride solution can be balanced become a solution by adding sodium chloride.

This part of the process can be used to treat ores containing silver, in which case the ore is roasted so that practically all of the lead and a large part of the silver is converted into the sulphates of these metals (PI) S04 A-, S04). The silver formed in this way is obtained in (colloidal) solution as a silver chloride (2 A-Cl) and precipitated with the lead when metallic iron is added to the solution, according to the following equations (using sodium chloride solution) Pb SO, + Ag2 SO, + 4 Na Cl 2 Ag Cl -j- Pb Cl, + 2 Na, SO ,, Pb Cl = + 2 AgCl -f- 2 Na2S O9 + 2 Fe - Pb + 2 Ag -j- 2 Fe C12 -f - 2 Na " SO ,. When using iron chloride solution, the reactions are as follows: PbS04 + Ag2S04 -f- --FeCl2 _-__ Pb C12 --f- 2 Ag c _ 1 + 2 Fe SO, Pb Cl, + 2 Ag Cl -E- z Fe S 04 + Fee = Pb -j- 2 Ag - @ 2 Fe C12 -} - 2 Fe S O4. After the lead and silver have precipitated, part of the solution is cleaned as required Sodium sulphate or ferrous sulphate crystallizes out, depending on the chloride solution used, the other part goes easily and continuously back to the stirrer-leachers uslauge stirred vessels returned.

The lead precipitates are washed and fused together as chloride Dissolved silver is also precipitated with the lead and then separated from it the ordinary refining method.

After, as mentioned above, the lead and some of the silver extracted from the ore, the residue is filtered by pressing and washed; the solution goes to the lead precipitation plant, the residue to the stirring and thickening vessels of the gold and silver operations of the plant, where the residue is still to be extracted Existing gold and silver leached with potassium cyanide and further on zinc dust It is precipitated in the manner generally customary in the cyanide process.

When executing the system for this process, the agitator vessels of the lead leaching plant are surrounded with masonry, possibly between (learn about the masonry and the outer wall of the lead-lined steel mixing vessels a gap is left through which the hot gases from the roasting ovens pass, to heat the chlorinated atrium fluids.

* As an example, the following is a system for carrying out the invention described in detail: Zinc-copper drive_ The roasted food is placed in a central chamber brought a Dorr thickening mixer; where stirring with air takes place; The apparatus is built in such a way that it can lead in the middle part, the sitting down of the back stand takes place in the outer part. The settled residues are drawn off at the bottom and at the top in the same stirrer or, if necessary, in a second one in the row pumped the following agitator thickener. From the top of this second thickener the clear solution returns to the first stirrer; the residue is from the bottom of the second mixer is pulled into a third thickener, from its Upper part of the clear solution is discharged into the second stirrer, the residues on the other hand, from the bottom of the third thickener into a filter press; from this one goes Residue in the lead operation of the plant, the filtrate, back to the third thickener and «-add to the second and the -first thickener.

Sulfuric acid is added to the first and second agitators at will added in such an amount that all soluble copper and zinc are dissolved in the roast and a neutral solution from the top of the first thickener to a fourth Stirrer passes over.

When the roasted food is stirred in the sulfuric acid solution with air in the first two stirrers, the iron is oxidized and ferric sulfate, Fez (S04) 3, is formed, as well as aluminum sulfate, Al. = (S04) 3.

This neutral solution is transferred to the fourth mixer, Zinc oxide is added and stirred with air.

The purpose of this is to form more zinc sulfate, Zn SO .., so that when electrolvsieren the acid bound as Fee (S04) 3, Al = (S04) 3 is obtained, and also one Part of the other impurities, such as bismuth, arsenic and antimony, from the solution to fell. The reaction that takes place in a solution containing Fe "(S04) 3, Al, (S04) 3, H, 0 takes place when stirring in the presence of zinc oxide is as follows: Fe2 (SO4) 3 -j- Al2 (S) Ja -I- 6H20 -f- 6U0-6 Zn S O4 -f- 2 Fe (O H) 3 + 2 Al (O H) ,,. Iron and Aluminum is precipitated as hydroxides. The felling of the fourth Stirrers will be added to the first stirrer if your zinc oxide gel is worth it returned, and (read zinc is obtained with the acidic solution; if it is too little contained, they are filtered by pressing and put away while the clear Solution goes into a fifth mixer.

The clear solutions from your fourth mixer will be in the fifth where, by adding iron powder, most of the copper, antimony, Bismuth and arsenic is felled.

The clear solution is from the fifth into a sixth agitator brought, the copper-containing residue is withdrawn from the fifth stirrer at the bottom and conveyed to a second filter press. The press cakes are melted, or they can be brought back to a roasting furnace 11n (1 i> ZV (Iiert, then in sulfuric acid dissolved and precipitated by electrolysis.

The filtrate from the second filter press goes to your sixth stirrer. In this, the last traces of Kadiniuni, iron, cobalt, nickel, Alltillion, bismuth, copper and arsenic like.

.111s this sixth mixer \\ - ground residues and solution below drained into a thickener; The clear solution is drawn off from diesels on a sand filter, and the precipitates will rise from the bottom of this thickener brought another filter. The filter cake is then cleared away and the filtrate returned to (lein last consignor.

The solution is freed from any sediment through (read sand filter and is cleaned in a Sainniel tank, from where the L5 solution is electrolytic Cells goes where the zinc is precipitated and sulfuric acid is regenerated; a part of the solution coming from the electrical (ilv table part) becomes -r_11 (lein Sainniel container returned to adjust the electrolyte accordingly, part goes iii Another storage vessel from which the acidic solution is sent to your first mixer goes back to leaching in fresh ore. Lead oil). The lead residue from the First filter press go into a Dorr mixer, where they are stirred in chloride solution will. Solution and pulp are drawn off at the bottom and placed in the: middle part of a (or several) thickener pumped. .111s this the pulp is drained below and pumped into the mixer, the clear solution is drawn off from the top of your thickener, directed to a sand filter and flows from this down to a felling box (drum), where the lead and silver are deposited on iron.

The solution flows from the bottom of the felling box into a crystallization vessel, where they cooled and sodium sulfate or ferrous sulfate crystallized out (or immediately returned to the stirrer).

The solution is then placed in a collecting container in which it if necessary adjusted to the required content by adding sodium chloride is, and then pumped back into the mixer in order to lye in the circuit Lead sulfate residue to be used.

`Penn all the lead is removed from the residue, they will be in the Ein (lickvor-, iitis directions pumped, from <nasty in a filter press, and washed; the filtrate goes back to the thickeners and the filter cake to the Gold and silver mining facility.

The clear solution from the thickeners goes to your sand filter, felling box, Crystallizing vessel, sanitary container and back 711111 stirrer (or directly zii the latter).

The lead precipitates are extracted from a felling box, in one I) relltronnliel washed and go from (la to the crucible, uni to the well-known ordinary alcohols fused and ingeniously grounded. Gold- and silver operation. The washed one removed from the filter press of the lead plant Filter cake is placed in a stirrer and finite in a zinc potassium solution Air stirred. The pulp is drawn off at the bottom of this one riddling apparatus, into the : Middle part of a Dorr-EindlckerS done and from the latter back to yours Stirrer. In this cycle the pulp is kept until the soluble gold and Silver are in solution. Then the pulp goes into a second thickener, where it becomes Settling is brought and further withdrawn from below in a filter press; after this if it is filtered and washed out, the press cake is cleared out.

The filtrate is fed into the second thickener, from this from at the top in the middle part of the first thickener, from the latter at the top to a clarifying filter and on to the felling boxes. In these, the gold is formed by the addition of zinc dust and silver is precipitated from the solution.

The clear solution is carried from the felling boxes into a collecting container, where it is adjusted to normal level with potassium vanide, and then to your first Stirrer returned. _ The gold and silver deposits are from brought the felling boxes to the refining plant, where the gold and silver are made according to the well-known ordinary methods to be divorced and refined.

The method described above represents a combination of which some elements are known per se; however, the overall procedure is new and causes a distinct new technical effect by attracting new ones valuable precipitating bodies made from composite ores that were previously worthless was. This progress is brought about by the second of the above sub-procedures, d. i. the new way of extracting lead and silver; this part is that missing link in a successful hydrometallurgical process for the separate extraction of the various metals from composite ores. This second sub-process can also be used for obtaining the Metals made from lead ores or lead and silver ores.

By uniting this (so far missing) link with known ones Method, the inventor has created a combination method which is a practical one successful treatment of any compound zinc, lead, copper, gold and silver ores made possible at a considerably lower cost than any other Procedure.

Claims (5)

PATENT CLAIMS: i. Process for the extraction of lead from composite, z. B. sulphidic ores, in which the lead is converted into sulphate and then through Treatment with a chloride solution is made soluble, in which further the lead is precipitated by a metal (such as iron), characterized in that the dissolved Lead is continuously removed during the dissolution process as it is dissolved will,. Such that the chloride liquor its ability to dissolve new amounts of lead sulfate retains. 2. The method according to claim i, characterized in that the precipitation of the lead, the iron chloride formed by iron to dissolve further quantities of lead sulphate is used so that further addition of chloride liquor is not necessary. 3. Design of the method according to claims i and 2, consisting in the extended Use on residues containing lead sulphate to recover the lead. q .. Method according to Claims i to 3, characterized in that at the same time as the lead silver is also drawn out. 5. Process for the treatment of lead, zinc, copper, gold- and silver-containing ores using the method according to claims i to q., consisting of the following measures: roasting the ore to convert lead and silver into sulphate, Convert zinc and copper into sulfate and oxide, complete conversion of zinc and copper oxide by sulfuric acid into sulphate, extraction of copper and zinc this sulfuric acid solution by electrolysis or otherwise, treating the lead and silver sulfate with a chloride solution (after removal of the soluble zinc and Copper), precipitation of lead and silver from this lye by adding iron or other metal and treating additional amounts of lead sulphate and silver sulphate with the chloride solution, treatment of the residues (after removal of the soluble copper, Zinc, lead and silver) with potassium cyanide to extract the gold and precipitation the gold from the solution by adding metallic zinc.