| Currently, cyanidation process of gold mining is widely used in gold extraction process. High concentrations of cyanide leaching will produce an extremely high concentration cyanide solution tail liquid. The waste water contains a variety of contaminants, for example: cyanide, heavy metal, heavy metals and cyanide complexes, thiocyanate, arsenic, ammonia and so on. If the waste water will not passed comprehensive management, it is absolutely not allowed emissions. So the main destination of high concentration or high concentration of cyanide solution tail liquid is used in the cycle for cyanide leaching process, but during the recycling process, various pollutants in the waste water will continue to accumulate, at the same time ion concentration will be gradually increased, it will affect the cyanide process indicators seriously, thereby affecting the economic benefits of the mine.Recent years, environmental lawsand regulations have been introduced,environmental protection is urgent. Zero emissions is strong advocate of cleaner production measures in our country, so whether from national policy or the treatment cost-benefit analyzed that to discharge waste water as a terminal manner inconsistent with the direction of sustainable development. In order to respond positively to the call of the state environmental protection, and promoting ecological construction of the mine, we should implement zero discharge and comprehensive utilization of waste water recycling resources such as energy measures, actively cyanide concentration was high most economical and rational governance is through recycling after proper treatment, it not only reduces the amount of fresh water mines, comply with clean production requirements, but also optimizes the cyanidation process of production targets, at the same time it can bring higher direct and indirect economic benefits for the mine.This paper reflects the purification and recovery, recycling, energy conservation,optimization of process indicators, etc. We have completed the experimental research laboratory and engineering applications. Cyanide designed liquid handling capacity of300 m3/d and the actual processing capacity of 360 m3/d. It has run so far nearly 4years and cumulated waste water treatment about over 400,000 m3, that includes product sodium cyanide purity is higher than 20 %, copper slag copper products by22 %-40 %, cumulative net benefit more than 8,000 million, all treated wastewater is used in recycling cyanide leaching process to protect the cyanide leaching process indicators effectively.The core of this technology is after a four-dimensional to the first negative pressure stripping precipitation, the core equipment is hydrocyanic acid in four-dimensional vacuum stripping device. Which overcome the traditional shortcomings of technological processes, such as: low cyanide recovery, process does not run continuously, insecurity, higher gas resistance. When we adopted new technologies, free cyanide removal rate was over 95.00 %, and the average removal rate of copper ions was over 99.00 %, then the hydrogen cyanide gas was all cycle absorbed, the recovering sodium from the process was all used in cyanide leaching,all copper slag which generating moisture content less than 30 % was all sold, so the cost of waste water treatment is only 33 % of the economic benefits.In addition, in order to prevent leakage of hydrogen cyanide gas, when we use the technology, we can put the high concentration of hydrogen cyanide gas blow-off area in the negative pressure zone. The process all used PLC automatic control technology, during normal operation, you can achieve unattended. At the same time,the process equipped with hydrogen cyanide gas leak emergency monitoring, early warning and emergency response system, the entire system security can be effectively guaranteed. The technology was awarded the china gold association of science and technology progress award, It has applied for ministry of environmental protection science and technology award. In addition, the technology selected for the fourth installment of mineral resources conservation and comprehensive utilization ofadvanced and applicable technologies to promote the directory, it ranked the non-ferrous and rare metals projects first.The technology is applicable to high concentrations of cyanide in different sectors of integrated wastewater treatment, such as gold industry, electroplating industry,coking industry, chemical industry, gas production industries, which all use cyanide or cyanide midwifery, therefore during the production process is bound to produce a certain amount of wastewater containing cyanide. The technology has made a breakthrough in the field of environmental protection technology, it provided a strong technical support for the high concentration of cyanide, heavy metals and other harmful ion containing cyanide wastewater comprehensive management. |
PDF Full Text Request