A high-arsenic pyrite concentrate alkali leaching pre-oxidation-calcium chloride synergistic dearsenization system and process thereof

The system of alkaline leaching pre-oxidation-calcium chloride synergistic arsenic removal at ambient temperature and pressure solves the problem of low cyanide leaching rate in high arsenic sulfur gold concentrate, achieving improved gold leaching rate and reduced cyanide consumption, and provides a highly efficient and environmentally friendly pretreatment process.

CN122303581APending Publication Date: 2026-06-30QINGHAI KUNLUN GOLD CO LTD
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Patent Information

Authority / Receiving Office
CN · China
Patent Type
Applications(China)
Current Assignee / Owner
QINGHAI KUNLUN GOLD CO LTD
Filing Date
2026-03-26
Publication Date
2026-06-30

AI Technical Summary

Technical Problem

Direct cyanidation leaching of high-arsenic-sulfur gold concentrate has a low leaching rate. During cyanidation, arsenic reacts with cyanide ions to form complexes, consuming cyanide and forming a passivation film on the surface of gold particles, which hinders the dissolution of gold. Existing pretreatment methods have problems such as environmental pollution, large investment, and long cycle.

Method used

An alkaline leaching pre-oxidation-calcium chloride synergistic arsenic removal system at ambient temperature and pressure is adopted, which includes fine grinding, pre-oxidation, calcium chloride reaction and solid-liquid separation. The minerals are oxidized by NaOH, and CaCl2•6H2O and lime are added to form stable calcium arsenate and calcium sulfate precipitates, thereby reducing cyanide consumption.

Benefits of technology

It can increase the gold leaching rate by 7-9 percentage points and reduce cyanide consumption by more than 30% under normal temperature and pressure, achieving efficient removal of arsenic and sulfur, and has good economic and environmental benefits.

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Abstract

This invention discloses a room-temperature and atmospheric-pressure alkaline leaching pre-oxidation-calcium chloride synergistic arsenic removal system and process for high-arsenic-sulfur gold concentrate. The process includes: fine grinding, alkaline pre-oxidation, calcium chloride synergistic arsenic and sulfur removal, solid-liquid separation, and cyanide leaching. In the alkaline pre-oxidation stage, NaOH is added and oxygen is introduced to achieve efficient oxidation of arsenic-sulfur minerals under room-temperature and atmospheric-pressure conditions. Subsequently, calcium chloride is added to rapidly precipitate arsenate and sulfate ions, forming stable calcium salt precipitates. This process effectively solves the problems of low cyanide leaching rate in high-arsenic-sulfur gold concentrate, equipment blockage caused by arsenic and sulfur accumulation in closed-loop circulation, and decreased leaching rate. Experimental results show that this invention can significantly improve the gold leaching rate and reduce cyanide consumption, demonstrating good industrial application value and economic efficiency.
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