CN1186867A - Method of extracting gold by mixed oxidant in cyaniding leaching - Google Patents

Abstract

According to the different property of gold containing ore, mixed oxidant of several kinds of four oxidants including compressed air, potassium permanganate, hydrogen peroxide and calcium peroxide is used in auxiliary gold leaching. This can raise leaching speed and leaching rate of gold and reduce consumption of cyanide. The present invention can produce ever high effect when used in leaching gold containing oxide ore with high grade and large viscosity and gold containing sulphide.

Description

During leaching, cyaniding extracts the method for gold with blending oxidizing agent

The present invention is relevant with the technical skill of cyanide gold-leaching.

It generally is in the presence of oxygen that the cyaniding of gold is leached, and the gold in the mineral is dissolved in the cyanide solution of alkalescence.For a long time, people adopt the way that feeds pressurized air (airborne oxygen is introduced ore pulp) in ore pulp to realize oxygen supply always, because airborne oxygen changes over to the ore pulp and to be diffused into the speed on goldc grains surface too slow from gas phase, this just must determine that this process is slowly on kinetics, particularly when handling some oxygen consumption or consumption cyanogen ore, the leaching velocity of gold is slow, and leaching yield is low, prussiate consumption height; " mining metallurgical engineering " 1993 Vol.13 Nol P49～51,54 have reported the experimental study situation of " application of hydrogen peroxide in cyanide gold-leaching technology ", test shows, though hydrogen peroxide can shorten extraction time, improve the leaching yield of gold, reduce the prussiate consumption, yet its oxidisability is too strong, except that the oxidizable element gold, also can destroy the leaching agent prussiate when consumption is big, even make some goldc grains over oxidation and passivation, along with the increase of hydrogen peroxide consumption, after taking the lead in increasing, the leaching of gold subtracts, in addition, hydrogen peroxide easily decomposes in ore pulp, and costs an arm and a leg.

At the problem that aforesaid method exists, the present invention intends adding blending oxidizing agent in the cyanide gold-leaching process, to reach the purpose that reduces the prussiate consumption in leaching velocity that improves gold and leaching yield.

It forms the blending oxidizing agent that the present invention selects for use and consumption following (logical air supply represents that with dissolved oxygen content other is an ore consumption per ton):

Pressurized air: 0～10ppm;

Potassium permanganate: 0～1kg/ ton ore;

Hydrogen peroxide: 0～0.5kg/ ton ore;

Calcium peroxide: 0～0.5kg/ ton ore; During concrete operations, different in kind according to gold containing ore, in the above-mentioned four kinds of oxygenants of optional usefulness two kinds, three kinds or all the blending oxidizing agent formed of oxygenant assist and soak gold, if selected pressurized air in the blending oxidizing agent for use, then in ore pulp, lead to pressurized air earlier, and then add other blending oxidizing agent by a certain percentage.

With regard to pressurized air, potassium permanganate, hydrogen peroxide, in the alkaline medium that cyaniding is leached, its oxidisability is by to weak order being by force: hydrogen peroxide

＞potassium permanganate

=0.588V)＞pressurized air

, it soaks gold reaction and is followed successively by: $2\mathrm{Au}+4C{N}^{-}+H_2{O}_2=2\mathrm{Au}{\left(\mathrm{CN}\right)}_2^{-}+2O{H}^{-}-----\left(1\right)$ $3\mathrm{Au}+6{\mathrm{CN}}^{-}+\mathrm{Mn}{O}_4^{-}+2H_{2}O=3\mathrm{Au}{\left(\mathrm{CN}\right)}_2^{-}+4{\mathrm{OH}}^{-}+\mathrm{Mn}{O}_2------\left(2\right)$ $4\mathrm{Au}+8C{N}^{-}+O_2+2H_{2}O=4\mathrm{Au}{\left(\mathrm{CN}\right)}_2^{-}+4O{H}^{-}-----\left(3\right)$ Calcium peroxide is made by hydrogen peroxide and liming reaction, it is slightly soluble in water, its oxygenizement produces hydrogen peroxide by its hydrolysis and realizes, compare with hydrogen peroxide, it is more stable in alkaline medium, its oxygenizement is balanced and slowly, can reduce direct adding hydrogen peroxide and the side reaction that produces, thereby its consumption lacks than hydrogen peroxide generally.

Gold containing ore is crushed to certain particle size (disseminated grain size on gold is decided), add tap water by certain liquid-solid ratio (deciding by test) on ore character, blending oxidizing agent is (if blending oxidizing agent has been selected pressurized air for use, that just earlier logical pressurized air, and then add other liquid-phase oxidation agent, the kind of blending oxidizing agent and the ratio of adding and consumption, decide on ore character) and prussiate (being generally sodium cyanide), use alkali (sodium hydroxide or liming again, be generally sodium hydroxide) regulate pH value to weakly alkaline (being generally 10～12), in stirred leaching tank, leach, leaching process finishes back (gained solution is the cyaniding leach liquor of gold), enter subsequent job again and further handle, to obtain highly purified gold mud or ingot.

The invention has the advantages that:

1. blending oxidizing agent can provide several oxygenants to participate in soaking gold reaction simultaneously, because the difference of goldc grains surface properties, the different oxygenant meeting of these oxidisability " is sat in the right seat " and " is found " its suitable separately goldc grains surface to work in ore pulp, gives full play to their advantages separately; In addition, liquid-phase oxidation agent (potassium permanganate, hydrogen peroxide and calcium peroxide) easily contacts with the goldc grains surface, thereby guaranteed the uniform distribution and the high utilization rate of active oxygen, this just fundamentally realizes improving the leaching velocity of gold and the purpose of leaching yield, and the consumption of simultaneous oxidation agent is also lower.

2. adopt the auxiliary gold that soaks of blending oxidizing agent, owing to need not the raising of (or minimizing) inflation (preventing or reduced the volatilization loss of prussiate) and leaching velocity, add liquid-phase oxidation agent such as hydrogen peroxide and can also make the sulfide surface oxidation and passivation, prevent that harmful ions such as Cu, S, Fe from reacting with prussiate, thereby can save prussiate in a large number.

3. the raising of cyaniding leaching rate can reduce the investment and the floor space of equipment, and the minimizing of the raising of gold leaching rate and prussiate consumption can obviously improve mine economic profit.

4. the auxiliary gold-leaching technology of blending oxidizing agent is simple, on existing equipment, can realize, its used oxygenant is cheap, wide material sources, easy to prepare (even cost an arm and a leg, as hydrogen peroxide, because its consumption is little, the expense that increases newly is also few, and the product that leaches reaction does not all influence the subsequent disposal operation.Thereby have broad application prospects.

5. with regard to ore character,, when, viscosity of high grade to handling is difficult to indissoluble gold ore deposit such as the oxidized ore inflated and consumption cyanogen oxygen consumption sulphide ores greatly, has stronger competitive power with the auxiliary gold that soaks of blending oxidizing agent.

Now leaching embodiment in conjunction with the cyaniding that contains gold mineral describes in further detail.

Embodiment 1:

The typical quartz vein in Hengyang, Hunan contains golden oxidized ore, and ore contains gold 8.25 gram/ton ores, ore oxidation degree height, and silt content is big, is difficult to inflation, and the major metal mineral are limonites, a spot of cupric oxide; Secondly gangue mineral is calcite based on quartz, a spot of kaolin.Handle by the inventive method, the processing condition that adopted are: the material grinding particle size is for to account for 80% less than 74 microns, liquid-solid ratio is 3: 1, ore pulp PH10～11 (regulating) with sodium hydroxide, other test conditions and test-results are as shown in table 1, for ease of relatively, logical compressed-air actuated data have also been listed in the table 1.

Test conditions and result's (table 1) under the different oxygen supply conditions

Test conditions	Extraction time (hour)	Dissolved oxygen content (PPm)	Blended liquid phase oxygenant consumption (kg/ton ore)	Sodium cyanide consumption (kg/ton ore)	Gold leaching rate (%)
						Pressurized air	???30	???10	????/	????2.0	?82.14
(calcium peroxide+potassium permanganate) 1: 2	???18	???/	????0.6	????1.0	?95.42

Embodiment 2:

Chenzhou, Hunan typically contains golden multi-metal sulfide, and ore contains gold 14.52 gram/ton ores, and the major metal mineral are pyrite and mispickel, are chalcopyrite, lead glance and zink sulphide secondly, and gangue mineral is based on quartz.Gold mineral is based on native state, and is in close relations with sulfide, and the distributive law of pyrite and mispickel gold accounts for more than 90%, and the disseminated grain size of gold is generally 0.060～0.015 millimeter.Handle by the inventive method, the material grinding particle size is to account for 80% less than 43 microns, and liquid-solid ratio is 2: 1, ore pulp PH10～11 (regulating) with sodium hydroxide, other test conditions and test-results see Table 2, for ease of relatively, also list logical compressed-air actuated data in the table 2.

Test conditions and result's (table 2) under the different oxygen supply conditions

Test conditions	Extraction time (hour)	Dissolved oxygen content (PPm)	Blended liquid phase oxygenant consumption (kg/ton ore)	Sodium cyanide consumption (kg/ton ore)	Gold leaching rate (%)
						Pressurized air	???48	???10	????/	????2.5	??70.02
Pressurized air+(calcium peroxide+hydrogen peroxide+potassium permanganate) 2: 3: 4	???24	????4	????0.9	????1.0	??94.58

Embodiment 3:

The Guizhou gold mine is for containing golden multi-metal sulfide, and ore contains gold 10.92 gram/ton ores, and the major metal mineral are pyrite, are chalcopyrite secondly, a spot of lead glance and zink sulphide, and gangue mineral is based on quartz.Gold is based on native state, and is in close relations with sulfide, and the distributive law of gold accounts for more than 80% in the pyrite, and the disseminated grain size of gold is generally 0.015～0.035 millimeter.Handle by the inventive method, material is crushed to less than 74 microns and accounts for 90%, liquid-solid ratio 2: 1, ore pulp PH10～11 (regulating) with sodium hydroxide, other test conditions and the results are shown in Table 3 for ease of relatively, has also been listed logical compressed-air actuated result in the table 3.

Test conditions and result's (table 3) under the different oxygen supply conditions

Test conditions	Extraction time (hour)	Dissolved oxygen content (PPm)	Blended liquid phase oxygenant consumption (kg/ton ore)	Sodium cyanide consumption (kg/ton ore)	Gold leaching rate (%)
						Pressurized air	???40	????10	????/	????2.0	??72.21
Pressurized air+(hydrogen peroxide+potassium permanganate) 2: 3	???24	????5	????1.0	????1.2	??98.88

Claims (4)

1. extract the method for gold during a cyaniding is leached with blending oxidizing agent, comprise and adopt pressurized air, hydrogen peroxide as oxygenant, it is characterized in that: selected blending oxidizing agent also comprises potassium permanganate and calcium peroxide, it is formed and consumption is: pressurized air 0～10ppm, potassium permanganate 0～1kg/ ton ore, hydrogen peroxidase 10～0.5kg/ ton ore, calcium peroxide 0～0.5kg/ ton ore, logical air supply represents that with dissolved oxygen content other consumption is an ore consumption per ton; Different in kind according to gold containing ore, in the above-mentioned four kinds of oxygenants of optional usefulness two kinds, three kinds or all the blending oxidizing agent formed of oxygenant assist and soak gold, if selected pressurized air in the blending oxidizing agent for use, then in ore pulp, lead to pressurized air earlier, and then add other blending oxidizing agent by a certain percentage.

2. method according to claim 1 is characterized in that: the blending oxidizing agent of selecting for use calcium peroxide and potassium permanganate to form, its blending ratio is 1: 2 (weight ratio).

3. method according to claim 1, it is characterized in that: the blending oxidizing agent of selecting for use pressurized air, calcium peroxide, hydrogen peroxide and potassium permanganate to form, logical pressurized air is to dissolved oxygen content 4ppm, and other oxygenant blending ratio is 2: 3: 4 (weight ratio).

4. method according to claim 1 is characterized in that: the blending oxidizing agent of selecting for use pressurized air, hydrogen peroxide and potassium permanganate to form, and logical pressurized air is to dissolved oxygen content 5ppm, and other oxygenant blending ratio is 2: 3 (weight ratio).