CN112111644A

CN112111644A - Method for efficiently recovering gold and silver

Info

Publication number: CN112111644A
Application number: CN202010945443.3A
Authority: CN
Inventors: 柯柏友
Original assignee: Individual
Current assignee: Individual
Priority date: 2020-08-31
Filing date: 2020-08-31
Publication date: 2020-12-22

Abstract

The invention discloses a method for efficiently recovering gold and silver, and relates to the field of metal metallurgy. The invention relates to an extraction method of sulfuric acid cinder and cyanidation tailings with high iron content and certain gold and silver content. The spongy reduced iron powder is prepared by adding reducing agents such as coal and the like and desulfurizing agents into sulfuric acid cinder and cyanidation tailings, mixing, adding into a roasting kiln, and carrying out reduction roasting. So that the wrapped micro-fine gold and silver particles are exposed in the sponge state of the reduced iron. And then the prepared spongy reduced iron powder is subjected to conventional gold and silver extraction, so that the gold and silver-containing material which is extremely difficult to leach is high in leaching rate. The sponge iron after gold and silver extraction is a valuable metallurgical chemical raw material, valuable metals can be efficiently and comprehensively utilized, precious mineral resources of China are fully utilized, and great wealth can be created for the society.

Description

Method for efficiently recovering gold and silver

Technical Field

The invention discloses a method for efficiently recovering gold and silver, and relates to the field of metal metallurgy.

Background

The sulfuric acid cinder is the waste residue discharged in the sulfuric acid production process, the waste residue for producing one ton of sulfuric acid is determined according to the sulfur content of pyrite, generally 0.8-1.1 ton, but China is a large sulfuric acid production country, thousands of tons of waste cinder are discharged every year, and part of the waste residue is sold to a cement plant at low price to be used as an additive or added to an iron-making plant for iron making; a considerable part of the water-soluble sulfate-containing organic fertilizer is stacked in the open air, not only occupies a large amount of cultivated land, but also can be oxidized into water-soluble sulfate to pollute stratum water systems under the action of bacteria after being placed for a long time, influences ecological balance and is a waste of resources. The pyrite cinder contains other valuable metal elements such as gold, silver, copper, cobalt and the like besides rich iron. However, valuable metals in the sulfuric acid cinder are difficult to extract due to the fact that the embedded particle size is fine and the attached condition is basically in a wrapping state, particularly gold and silver are extracted, the roasting temperature for acid preparation is higher, micro-fine-particle gold is wrapped again, the leaching rate is low, and the extraction value is lost. The development of the research on the high-efficiency comprehensive utilization of the cinder is an ideal way for changing waste into valuable, and has important significance for improving the economic benefit of enterprises and preventing and treating the environmental pollution.

The cyanidation tailings are tailings of cyanidation gold extraction after roasting of flotation gold concentrate, and China is a country with more gold production and produces a large amount of cyanidation tailings in the production. The cyaniding tailings are mostly powder, have fine granularity, and contain elements such As Ag, Fc, S, Cu, Pb, As, Zn and the like besides gold with relatively low grade. However, valuable metals in the cyanidation tailings are difficult to extract, particularly gold and silver are not leached during cyanidation, and are micro-fine nano-grade gold wrapped in iron, sulfur, arsenic and other gangue under the condition of severe wrapping. It is determined that the leaching rate is low and the extraction value is lost. The enrichment is carried out by mineral separation processes such as gravity separation, magnetic separation, flotation and the like, but the method is rarely applied due to low recovery rate and poor enrichment effect. However, a large amount of cyanide tailings not only occupy the land, but also pollute the air, and if the cyanide tailings are washed into a river channel by rainwater, heavy metals in the cyanide tailings can also pollute the water body. The efficient comprehensive recycling of the cyanidation tailings has social and economic benefits and has practical significance for solving the environmental pollution.

At present, the yield of the sulfuric acid residues and the cyanidation tailings in China is large, the sulfuric acid residues and the cyanidation tailings are used as secondary resources to be comprehensively utilized, and the comprehensive recovery of valuable metals is significant.

Disclosure of Invention

Aiming at the defects and shortcomings in the prior art, the invention discloses a method for efficiently recovering gold and silver, which comprises the steps of adding reducing agents such as coal and the like and desulfurizing agents into sulfuric acid cinder and cyanidation tailings which have high iron content and certain gold and silver content, mixing, adding into a roasting kiln, and carrying out reduction roasting to obtain spongy reduced iron powder. So that the wrapped micro-fine gold and silver particles are exposed in the sponge state of the reduced iron. And then the prepared spongy reduced iron powder is subjected to conventional gold and silver extraction, so that the gold and silver-containing material which is extremely difficult to leach is ultrahigh in leaching rate.

A method for efficiently recovering gold and silver is characterized by comprising the following steps: firstly, adding reducing agents such as 20-35% of coal powder and the like and 3-5% of desulfurizer calcium carbonate stone powder into sulfuric acid cinder and cyanidation tailings which have high iron content and certain gold and silver content, mixing, adding the mixture into a roasting kiln for reduction roasting, controlling the roasting temperature at 1100-1200 ℃, roasting for 1-4 hours, discharging the mixture out of the kiln, grinding and magnetically separating to obtain spongy reduced iron powder with the iron content of over 91%, adding the prepared spongy reduced iron powder into a stirring tank for size mixing, adding lime for regulating the pH value to 11, and adding sodium cyanide or an environment-friendly gold extraction agent for conventional gold and silver leaching. The original wrapped micro-fine gold and silver particles are exposed in the sponge state of reduced iron, which is greatly beneficial to leaching of the gold and silver. Therefore, the recovery rate of the gold and silver can reach more than 90 percent. The sponge iron after gold and silver extraction is a valuable metallurgical chemical raw material with a value more than enough to the reduction roasting cost of the reduced iron. The profit value of extracting the gold and silver is the earning! The method can efficiently and comprehensively utilize valuable metals, fully utilize precious mineral resources of China, and has remarkable social benefit and economic benefit.

Detailed Description

The invention will be further understood with reference to the following specific examples.

Example 1

The sulfuric acid cinder of a certain sulfuric acid plant in Anhui Anqing contains 56% of iron, 1.7% of sulfur, 2.65g/T of gold and 36g/T of silver, is added with 35% of reducing agents such as coke powder and 3% of desulfurizer calcium carbonate stone powder, is mixed and stirred uniformly, is added into a roasting kiln for reduction roasting, the roasting temperature is controlled to be 1100-1150 ℃, the mixture is discharged from the kiln after being roasted for 4 hours, and spongy reduced iron powder is prepared by grinding and magnetic separation, wherein the iron content is 91.5%. And adding the prepared spongy reduced iron powder into a stirring tank for size mixing, adding lime for regulating the pH value to 11, adding 1.5kg of environment-friendly gold extracting agent per ton of ore, adding activated carbon for full-peat pulp gold and silver extraction, and leaching for 24 hours. The gold residue in the test tailings is 0.17g/T and the silver residue is 7.3g/T, the leaching rate of the gold is up to 93.5 percent, and the leaching rate of the silver is 79.7 percent, so that the satisfactory effect is achieved.

Example 2

The cyanidation tailings of a certain gold smelting plant of Henan Lingbao contains 59.3 percent of iron, 2.3 percent of sulfur, 4.65g/T of gold and 47g/T of silver, 30 percent of reducing agent such as coke powder and 5 percent of desulfurizer calcium carbonate stone powder are added into the cyanidation tailings, mixed and stirred uniformly, added into a roasting kiln for reduction roasting, the roasting temperature is controlled to be 1100-1150 ℃, the mixture is discharged from the kiln after being roasted for 3.5 hours, and spongy reduced iron powder is prepared by grinding and magnetic separation, wherein the iron content is 92.3 percent. And adding the prepared spongy reduced iron powder into a stirring tank for size mixing, adding lime for regulating the pH value to 11, adding 1.8kg of environment-friendly gold extracting agent per ton of ore, adding activated carbon for full-peat pulp gold and silver extraction, and leaching for 24 hours. The gold residue in the test tailings is 0.33g/T, the silver residue is 9.0g/T, the leaching rate of the gold is as high as 92.9 percent, the leaching rate of the silver is 80.8 percent, and a satisfactory effect is achieved.

Example 3

Cyaniding tailings of a gold smelting plant, which is located in Shandong province, contains 55.7% of iron, 2.3% of sulfur, 5.75g/T of gold and 53g/T of silver, and is prepared by adding 30% of reducing agents such as coke powder and 5% of desulfurizer calcium carbonate stone powder, mixing and stirring uniformly, adding the mixture into a roasting kiln for reduction roasting, controlling the roasting temperature at 1100-1150 ℃, roasting for 4 hours, discharging the mixture out of the kiln, grinding ore and magnetically separating to obtain spongy reduced iron powder with the iron content of 91.0%. And adding the prepared spongy reduced iron powder into a stirring tank for size mixing, adding lime for regulating the pH value to 11, adding an environment-friendly gold extracting agent of 2.3 kg/ton ore, adding activated carbon for full-peat size gold and silver extraction, leaching for 24 hours, testing the tailings of gold residues of 0.35g/T and 8.7g/T, wherein the leaching rate of gold is up to 93.9 percent, and the leaching rate of silver is 83.5 percent, so that a satisfactory effect is achieved.

Claims

1. A process for recovering gold and silver efficiently includes such steps as mixing the sulfuric acid dregs and cyanidation dregs with high iron content and a certain content of gold and silver with coal and desulfurizing agent, and calcining in kiln to obtain spongy reduced iron powder. So that the wrapped micro-fine gold and silver particles are exposed in the sponge state of the reduced iron. And then the prepared spongy reduced iron powder is subjected to conventional gold and silver extraction, so that the gold and silver-containing material which is extremely difficult to leach is high in leaching rate.

2. The method for efficiently recovering gold and silver as defined in claim 1, wherein: firstly, sulfuric acid cinder and cyanidation tailings which have high iron content and certain gold and silver content are mixed with reducing agents such as coal and the like and desulfurizing agents, the mixture is added into a roasting kiln for reduction roasting to prepare spongy reduced iron powder, and then the prepared spongy reduced iron powder is subjected to conventional gold and silver extraction.