A process for advanced impurity removal and resource recovery of gold smelting wastewater

Abstract

The invention discloses a process for deep impurity removal and resource recovery of gold smelting wastewater, comprising the following steps: firstly using mineralization vulcanization chemicals to remove zinc in barren wastewater under the conditions of pH values ​​of 5-6 and 2.5-3 in sequence and copper, then carry out acidification stripping and neutralization reaction at the pH value of 1.5-2, 8.5-9.5, and finally introduce sulfur dioxide gas for aeration treatment to complete the deep impurity removal and resource recovery of lean liquid wastewater. The mineralization vulcanization agent used is prepared by mixing ferrous sulfate, calcium sulfide and water. The process of the present invention has the advantages of high safety factor, high treatment efficiency, good impurity removal effect, high resource recycling benefits, and environmental protection. The ferrous ions, calcium ions and sulfate ions contained in the mineralization vulcanization agent will basically not remain in the liquid after cyanide removal, so the use value is high and the application prospect is good.

Description

technical field [0001] The invention belongs to the field of gold smelting wastewater treatment, and in particular relates to a process for deep impurity removal and resource recycling of gold smelting wastewater. Background technique [0002] The cyanidation gold extraction process in the gold smelting production process is currently the most important gold extraction method because of its high recovery efficiency and many other advantages. Among them, the filtrate produced after the replacement of the rich gold and precious liquid zinc powder in the gold smelting production process is It is poor liquid wastewater, which contains valuable metal impurity ions zinc and copper, as well as valuable recyclable cyanide, and is a kind of waste water capable of recycling. [0003] At present, the conventional method for treating barren wastewater is the acidification stripping method, in which in the direct acidification process of barren wastewater, the cyanide complexed with zinc...

AI Technical Summary

Problems solved by technology

The main disadvantages of this traditional treatment process are: the concentration of cyanide in the treated liquid is too high to meet the discharge requirements, and advanced treatment is required; the acidification process produces mixed metal slag, including cyanide ions converted by metal copper ions during the acidification process. Copper precipitation, which is a highly toxic substance, that is, the mixed metal slag produced during the acidification process is a hazardous waste that cannot be sold directly and the economic efficiency of the metal slag treatment process is low

However, the existing method of combining sulfuration and acidification still has the following defects: (a) not only includes sulfuration and acidification treatment steps, but also ultrafiltration / nanofiltration treatment steps, the treatment process is long, the treatment efficiency is low, and the treatment cost is high , low return on recycling

(b) The vulcanizing agent used is sodium sulfide or sodium hydrosulfide, which is easy to introduce a large amount of sodium ions, resulting in an increase in the salinity of the system, low resource utilization benefits, or even no profit. At the same time, due to the sodium sulfide or sodium hydrosulfide The activity is strong, and it will react rapidly during the acidification process and convert a large amount of hydrogen sulfide gas, which will increase the amount of acid used in the acidification process, and the existence of newly generated hydrogen sulfide gas requires more safety precautions for the processing equipment / processing system. High, there is also a certain security risk

(c) In the existing vulcanizing agent, in addition to introducing a large amount of sodium ions, other impurities may also be introduced. If the vulcanizing agent used contains Mn 2+ or Zn 2+ When used, these metal impurities will enter the decyanide solution, which will affect the recycling value of the decyanide solution, and even cannot be reused in the cyanide gold extraction process of gold smelting production.

(d) In the existing treatment process, it is difficult for the vulcanizing agent to remove zinc and copper in the wastewater quickly and efficiently. As a result, the concentration of zinc ions and copper ions in the liquid after vulcanization is still high, while the concentration of zinc sulfide slag and copper sulfide slag The purity of zinc and copper is relatively low. At the same time, there are still defects in the concentration of cyanide and heavy metals that exceed the standard after adding lime to adjust the pH value of the solution after sulfidation and copper removal. It cannot be directly discharged or directly returned to the production process, that is, the existing treatment The impurity removal effect of the process still needs to be improved, and it is difficult to obtain zinc sulfide slag and copper sulfide slag with high recovery value, and it is difficult to realize the resource utilization of the liquid after cyanide removal

(e) In the existing recycling process, the treatment method of tail gas is mainly to pass the tail gas directly into the lye, and convert it into a mixed salt solution of sulfide salt and cyanide salt by reacting with the lye, but the mixed salt solution cannot Directly returned to the production system for use; at the same time, in the existing treatment process, different types of gases in the tail gas are not treated separately, and different types of gases in the tail gas cannot be recovered separately, so it is difficult to realize the effective resource utilization of the tail gas

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