On January 9, the National Science and Technology Awards Conference was held at the Great Hall of the People in Beijing. At the conference, the research results of "Key Technologies for Treatment and Clean Utilization of Arsenic-containing Solid Waste in Nonferrous Smelting" completed by more than 10 lead, antimony and copper nonferrous smelting enterprises won the second prize of the National Science and Technology Progress Award.
The pollution prevention and safe disposal of arsenic-containing solid waste in nonferrous smelting has always been a major problem in my country's nonferrous metals and environmental protection industries. Arsenic-containing solid waste has various forms and different components, and is often accompanied by valuable elements such as gold, silver, antimony, bismuth, and tellurium. The traditional treatment and utilization process unilaterally pursues the recovery of valuable metals and ignores the prevention and control of arsenic pollution. Not only is the resource utilization rate low, but the arsenic flow in the whole process is out of control and secondary pollution is serious, which urgently needs technological innovation.
With the support of the National 863 Program key projects, the National Environmental Protection Public Welfare Industry Scientific Research Project, the National Natural Science Outstanding Youth Fund, and the Hunan Provincial Science and Technology Major Project, the project is based on the major strategic needs of the country's heavy metal pollution prevention and control, with the goal of preventing and utilizing arsenic pollutants in non-ferrous smelting such as copper, lead, and antimony. Focusing on key technologies such as efficient treatment of arsenic-containing solid waste and clean recovery of valuable metals, a series of new processes and complete sets of equipment have been developed, which have been widely promoted and applied in large-scale copper, lead, and antimony non-ferrous smelting enterprises in my country. In the past three years, a total of about 160,000 tons of arsenic-containing solid waste have been cleanly utilized, about 12,000 tons of arsenic have been safely disposed of, and the recovery of valuable metals has achieved an additional output value of about 4.676 billion yuan, with profits and taxes of 349 million yuan. The main innovations are as follows: a mathematical model of arsenic distribution behavior in the non-ferrous smelting process was constructed, a numerical simulation technology for the distribution of arsenic pollutants in the main smelting process was developed, and a dynamic evaluation system for smelting harmful elements (arsenic) pollution was developed, providing a scientific basis for the prevention and control of arsenic pollution in non-ferrous smelting; in response to the problem of separation and utilization of multi-metal arsenic-containing solid waste, the selective separation mechanism of arsenic and similar elements was revealed, a new process for efficient separation of arsenic and valuable metals was invented, and a high-pressure oxygen-enriched enhanced arsenic removal device was developed. The selective removal rate of arsenic in arsenic-containing solid waste reached 97.42%, providing technical support for the clean utilization of arsenic-containing solid waste; in response to the problem of disposal of arsenic-containing hazardous waste, a new process of mechanochemical detoxification-gelation arsenic was developed, a new technology for hot-pressing and melting solidification of arsenic-containing solid waste was developed, and a new method for arsenic precipitation and stabilization of high-arsenic waste liquid was invented, forming a new high-density arsenic solidification technology that meets various needs; the leaching toxicity index of solid arsenic after disposal is better than the relevant national standards (GB 18598-2001), the arsenic content can reach 27%, achieving high-density and safe solid arsenic; in order to solve the problem of efficient recovery and utilization of valuable metals in dearsenicized materials, a new process for cascade recovery of antimony, bismuth and other metals from valuable materials after dearsenicization was invented, and a new process for deep separation of arsenic alkali slag and recovery of antimony alkali was invented, which increased the recovery rate of bismuth from 40% of the original process to 96%, and the annual recovery of bismuth reached 10% of the global total, and the utilization rate of antimony increased from less than 40% of the traditional process to more than 95%. At present, this technical achievement has been included in the "National Advanced Pollution Prevention and Control Demonstration Technology List", and has been promoted and applied in more than 10 lead, antimony and copper non-ferrous smelting enterprises, playing an important leading role in the control and clean utilization of arsenic solid waste pollution in my country's non-ferrous industry, with significant social and economic benefits and broad application prospects.
