CN1047699A - From difficult-treating gold mine, reclaim gold and silver - Google Patents

Abstract

The invention belongs to the difficult method of smelting precious metal ore recovery gold and silver of hydrometallurgical recovery.With the difficult gold mine of smelting of copper bearing ammoniac thiosulfate solution leaching.Add an amount of vitriol and replace unsettled sulphite, when solution circulated is used, need not replenish sulphite, thereby reduce the consumption of reagent, the technology that makes thiosulfate technique carry gold realizes industrial production easily.

Description

From difficult-treating gold mine, reclaim gold and silver

The present invention belongs to Wet-process metallurgy method to reclaim precious metal, particularly belongs to the technology of using the hydrometallurgical recovery gold and silver from difficult-treating gold mine.

From ore, extract gold at present and run into unmanageable complicated ore, particularly cupric more and more, contain ore such as manganese, be difficult to handle them with cyanide process.In addition, prussiate is a highly toxic substance, easily causes environmental pollution; Another shortcoming of cyanide process is that reagent is expensive.As use high density, cost is improved.For this reason, both at home and abroad all at the non-cyanidation technique of research.For cupric, contain gold and silver in the sulphide ores such as manganese, be a reasonable method with copper bearing ammoniac thiosulfate solution leaching because speed of response is fast, the extraction yield height of gold, leach used sulfur-bearing cupric component can generation on the spot from ore.This method is based on thiosulfate anion can generate stable complex compound with gold and silver in alkaline medium.

Reaction is in the presence of cupric ion:

In the presence of oxygen:

Because thiosulphate toxicity is little, leaching liquid can be recycled again, so do not pollute the environment; Thiosulphate leaches so can use than higher concentration than prussiate considerably cheaper on the other hand, thereby shortens leaching time.

This method as far back as the 1900's just the someone propose.Afterwards, the Soviet Union, Japan carried out fundamental research to this process.Find that cupric ion has booster action to this process.But these researchs are all carried out under High Temperature High Pressure.Up to Canadian Berezowsky(U, S in 1978, Pat.No.4,070,182) propose about 60 ℃, under normal pressure, handle the slag that soaks that ammonia soaks behind the copper-sulphide ores with thiosulfate solution and reclaim after the gold and silver, just make this process have realistic meaning.But he does not solve S ₂O 2- ₃Instability problem.B.J.Kerley (U.S.Pat.NoS.4,269,622 and 4,369,061) in two parts of patents points out, in order to make S in the solution ₂O 2- ₃Keep stable, can add 0.1-2%SO 2- ₃He thinks S in basic solution ₂O ₃Disproportionation reaction easily takes place:

So SO 2- ₃Existence can suppress S ₂O 2- ₃Disproportionation reaction.He points out that simultaneously pH value of solution preferably remains on 8, and temperature is 50-60 ℃ scope.Though Kerley under lab obtains good result, still according to his experimental result, the factory that sets up can not normal running.Perez etc. (U.S.Pat.No.4,654,078) point out that this is because the pH of solution is low, contains iron in the leaching liquid, makes S ₂O 2- ₃Be decomposed into S ₄O 2- ₆Thereby hindered the leaching of precious metal.So they bring up to 9-10.5 with pH value of solution, make the iron oxidation precipitation, be beneficial to the leaching of precious metal.

Kerley and Perez have emphasized SO 2- ₃For stablizing S ₂O 2- ₃Vital role, but all not mention sulphite itself be a unsettled material, it is can oxidized (as reacting shown in 5) in the leaching process.In order to keep certain SO 2- ₃Concentration needs

Constantly add sulphite.Consequently the loss of thiosulphate is converted into the loss of sulphite, does not fundamentally solve the problem of reagent exorbitant expenditure.

The present invention is in order to address this problem, to U, S, Pat.NoS.4,269,622,4,369,061 and 4,654,078 process that is proposed is improved, and promptly replaces sulphite with vitriol, so as economically from refractory ore particularly cupric, contain and reclaim Jin Heyin the manganese ore.Therefore the scope of application of this process and Kerley, Perez etc. are described together.In brief, in order to reclaim cupric, to contain gold and silver-colored in the sulphide ores such as manganese, the cupric 0.5-4g/l of available pH 9-11, (0.05-0.4%); S ₂O 2- ₃0.2-1M; NH ₄The solution of OH 0.4-2.2M in oxygen-containing atmosphere, leached 0.5-4 hour under 40-60 ℃, and thiosulphate decomposes the vitriol that can add 0.05-1M in the leaching process in order to suppress, as sodium sulfate, vitriolate of tartar, ammonium sulfate etc.Principle process is seen accompanying drawing.Wherein

1, leaching; 2, liquid-solid separation; 3, displacement; 4, sour molten slag;

5, roasting; 6, system (NH ₄) ₂S; 7, system (NH ₄) ₂S ₂O ₃;

8, system (NH ₄) ₂SO ₃

Dotted line partly represents to use instead the sulphite part of being saved behind the vitriol among the figure.(chemical industry metallurgical 1989,2, the iron substitution method that 45-50) is proposed reclaims golden available Hu Jiexue etc. in the leaching liquid.

Can see SO from reacting 5 2- ₄Concentration increases, and reaction is carried out left.SO 2- ₃The concentration increase promotes to react 4 again and carries out left, plays the effect of stablizing thiosulphate.Therefore because vitriol is a highly stable material, leaching process can not consume, and displacement back tail washings returns when using, and does not need picture to replenish sulphite and (or replenishes superfluous S °, or replenish superfluous SO ₂, NH ₃) additional like that vitriol.Only need begin to add a small amount of vitriol just can be recycled (being that dotted line has partly saved among Fig. 1) at the leaching process first time.This will significantly reduce reagent consumption.(loss of just superfluous sulphite or superfluous sulphur has been avoided fully.) for example, domestic certain replica plant's experimental result shows that one ton of ore deposit of every processing consumes 18Kg(NH ₄) ₂S ₂O ₃, 76Kg SO ₂, 18Kg NH ₃As use this development, so most of SO ₂Consumption can save.In the described circulation experiment of Kerley patent (U, S, Pat.No, 4,369,061), be actually with superfluous sulphur and suppress S ₂O 2- ₃Decompose.Shown in equation 6.

As use this development, superfluous sulphur action required of floatation recovery and expense all can be saved after superfluous sulphur reached.

Demonstrate it below

Example 1

The variation of sulfur-bearing component in leaching process in the leaching liquid measured, and measurement result sees Table 1.It show following some: (1) sulphite is very unsettled, be added in the solution after, very fast decomposition; (2) in the solution that only adds thiosulphate, also contain SO 2- ₃And S ^2-, illustrate that disproportionation reaction exists; (3) in the thiosulfate solution as do not add sulphite or vitriol, the thiosulphate loss is more; (4) only add ammonium sulfate and do not add sulphite

Table 1, leaching process sulfur-bearing component change in time

NH ₄OH 2.0M;Cu ⁺⁺1g/l;

Liquid: Gu=4: 1; O ₂1 liter/minute; Mechanical stirring

The thiosulfuric acid salt system in do not detect SO from start to finish 2- ₃And S in the system ^2-May not from S ₂O 2- ₃Disproportionation reaction but from the decomposition of sulphide ores.

These results show that vitriol exists increases the thiosulfuric acid salt-stable.

Example 2

With the thiosulfate solution leaching cupric gold sulphide concentrate that contains vitriol, sulphite respectively, its leaching the results are shown in Table 2.It shows and does not add sulphite, the leaching system of vitriol, and golden leaching rate is low.It is about the same with the leaching result who adds sulphite to add vitriol.Be the existence of vitriol, improved golden leaching yield.

Table 2 leaching experimental result

Ore: Au 50.4g/t; Ag 0.0078g/t; MnO ₂0.048%; Fe ₂O ₃: 28.9%;

Cu????????3.19%;C????????0.42%;S????????20.6%;

[NH ₄OH] 2.0M; [S ₂O 2- ₃] 1.0M; Cu ⁺⁺1g/l; O ₂1 liter/minute; Mechanical stirring

Example 3

Handle the few gold sulphide concentrate of another cupric with the described condition of table 2, it contains Au 74.4g/t; Ag 91.4g/t; Cu 0.33%; Fe 39%, and the golden leaching rate in leaching back is～94%, and silver-colored leaching rate is～80%.

Example 4

Use thiosulfate solution, not only can leach gold in the sulphide ores, also can leach gold in the oxidized ore.For example an oxidized ore contains: 53.2% SiO ₂; 16.7% Al ₂O ₃; 10.5% Fe; 3.4% TiO ₂; 0.15% P; 0.16% CaO; 0.55% MgO; 0.027% S; 0.44% As; 3.8% K ₂O; 0.04% Na ₂O; 8.6g/t Au.It is following to containing Cu 1g/l at 40 ℃; Na ₂S ₂O ₃1.0M; NH _{4 4}OH 2.0M; (NH ₄) ₂SO ₄0.3M solution leaching after, gold drops to below the 0.3g/t in the slag.

Example 5 circulation experiments

Leaching liquid if can recycle, and will reduce cost greatly, and help the popularization of this technological process.A circulation comprises leaching, replacement process, and the solution after the displacement will replenish thiosulphate, ammonium hydroxide, makes their concentration equal before the leaching for the first time in the solution separately concentration, is used further to leaching, no longer supplementation with copper ion and vitriol.7 circulations have been carried out altogether.Leach for the 7th time 96.8% leaching rate.Each time leaching rate with the first time leaching rate compare about fluctuation ± 1%.Experiment showed, that leaching liquid can be recycled.

Test used ore and form, with table 2.

Leach for the first time experiment condition:

1.0M Na ₂S ₂O ₃; 2.2M NH ₄OH; 0.4M(NH ₄) ₂SO ₄; 1g/lCu ⁺⁺; Liquid: Gu=2: 1; 36～42 ℃; Leaching time 1.5 hours; Mechanical stirring; Po ₂=1 liter/minute.

Permutizer condition:

Use iron replacement; Fe: Cu=2: 1; 40 ℃; Time swap one hour; Mechanical stirring.

Claims (2)

1, with the difficult method of smelting gold and silver ore of copper bearing ammoniac thiosulfate solution leaching, comprise with cupric 0.5～4g/l, contain thiosulphate 0.2～1M, the solution that contains ammonium hydroxide 0.4～2.2M, under the condition of pH9-11 and 40～60 ℃, leach ore in the oxygen-containing atmosphere, it is characterized in that adding in the leaching liquid vitriol more than 0.1% to replace the sulphite of former interpolation, make when utilizing circulation fluid again, need not to add vitriol and sulphite as leaching liquid.

2, require 1 described method according to patent, it is characterized in that the vitriol that adds can be ammonium sulfate, sodium sulfate, vitriolate of tartar.

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