The non-ferrous metal minerals commonly found in gold ore and their effects on the cyanidation of gold are as follows:
1. copper mineral ores copper minerals, such as chalcopyrite, bornite, chalcocite, azurite, malachite, etc., and natural copper cyanide can be consumed with a cyanide reacts with copper cyanide complex salt . The solubility of various minerals in cyanide solutions is shown in the table below.
Solubility of copper minerals in 0.099% NaCN solution
Mineral name | Minute  child  formula | Copper dissolution rate ( % ) | |
Metal copper Azurite Copper mine  Chrysocolla Copper ore Chalcopyrite Copper ore malachite  Sulfur arsenic copper ore Beryllium copper mine | Cu 2CuCO 3 · Cu(OH) 2 Cu 2 O CuSiO 3 Cu 2 S CuFeS Fe S · 2Cu 2 S CuS CuCO 3 · Cu(OH) 2 3Cu S · As 2 S 5 4Cu 2 S · Sb 2 S 3 | 90.0 94.5 85.5 11.8 90.2 5.6 70.0 90.2 65.8 21.9 | 100.0 100.0 100.0  15.7 100.0  8.2 100.0 100.0  75.1  43.7 |
For different copper minerals, typically 0.1 to 3.4 grams of cyanide is consumed per 1.0 gram of copper dissolved, and sometimes oxygen in the solution is also consumed.
Since the cyanide solution interacts strongly with many copper minerals, it is difficult to extract gold by cyanidation in the presence of excess copper minerals. However, when the cyanide concentration is lowered, the strength of action between copper minerals and cyanide drops sharply. Therefore, low-concentration cyanide solution is used in industrial production to treat copper-bearing gold ore. In order to facilitate the smooth progress of cyanide, the content of copper in the cyanide ore should be controlled below 0.1%.
2. The zinc mineral oxidized by zinc mineral is easily dissolved in the cyanide solution, and the unoxidized sphalerite is slightly reacted with the cyanide solution to form zinc cyanide salt and thiocyanate. The metal zinc is in the cyanide solution. Dissolving is faster than gold. The solubility of various zinc minerals in cyanide solutions is shown in the table below. In general, when the dissolved zinc content in the cyanide solution reaches 0.03 to 0.10%, it affects the dissolution of gold.
Solubility of zinc minerals in sodium cyanide solution
Mineral name | Minute  child  formula | Zinc content ( % ) | Zinc dissolution rate ( % ) | |
Raw ore | Leaching | |||
Sphalerite Siliceous ore Water zinc mine Heterogeneous mine Zinc iron spinel Red zinc mine Sphalerite | ZnS ZnSiO 4 3ZnCO 3 · 2H 2 O H 2 Zn 2 SiO 5 (Fe, Mn, Zn)O (Zn,Mn)Fe 2 O 4 ZnO ZnCO 3 | 1.36 1.22 1.36 1.19 1.19 1.22 1.22 | 1.11 1.06 0.78 1.03 0.95 0.79 0.73 | 18.4 13.1 35.1 13.4 20.2 35.2 40.2 |
When sphalerite is dissolved in a cyanide solution, there are zinc complex salts, thiocyanates, sulfates, and intermediate sulfides in the solution. The formation of these compounds consumes a large amount of oxygen and cyanide, and therefore, sphalerite has a certain adverse effect on gold leaching. Various types of zinc oxide will form zinc complex salts in the cyanide solution, and zincate will also be formed in the alkaline solution, which has an adverse effect on the cyanidation leaching of gold.
3. Lead minerals Common galena in gold ore. When the amount of lead in the ore is appropriate, cyanidation of gold is often advantageous. Since the harmful effects of lead can be eliminated cyanide solution of alkali metal sulfide, can promote the precipitation of gold when replaced, but also to promote the dissolution of silver gray silver ores. Excess lead in the solution is unfavorable for gold leaching. Especially when lime is used as a protective base, the leaching rate of gold will decrease significantly with the increase of lime dosage. At the same time, the consumption of zinc will increase after the replacement operation, and the gold grade of the gold mud will be lowered.
Unoxidized galena has a weaker effect on cyanide, producing NaCNS and Na 2 PbO 2 . The lead oxide mineral can be dissolved in the cyanide solution to form a lead salt, and then reacted with the soluble sulfide to form a PbS precipitate.
4. Antimony minerals The common antimony mineral in gold-bearing ore is stibnite. Although the stibnite does not directly interact with the cyanide solution, it is well soluble in alkali, which produces cyanide and thio sulphite and cyanide and oxygen in the solution until the sulphide is completely changed. Until the formation of oxides.
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