On August 2nd, China Nonferrous Metals Industry Association organized an expert meeting on scientific and technological achievements in Kunming, Yunnan Province, and completed the “electrolytic aluminum overhaul slag” jointly completed by Zhengzhou Hongyue Environmental Protection Technology Co., Ltd., Hunan Zhongda Metallurgical Design Co., Ltd. and Zhengzhou University of Light Industry. The method of acid-free treatment and industrialization is to evaluate the scientific and technological achievements. The evaluation expert group is Vice President of China Nonferrous Metals Industry Association, Chairman of the China Nonferrous Metals Society, Professor Jia Mingxing, Academician Zhang Wenhai of China Ruilin Engineering Technology Co., Ltd., Academician Huang Xiaowei of Yanken Technology Group Co., Ltd., and Assistant Professor Li Wei of the President of Zhongnan University. Professor Zhang Ting’an, the director of the Northeast University Library, Professor Yang Bin, the vice president of Kunming University of Science and Technology, and the academician and expert of Guodiantou Qingtongxia Aluminum Industry Niu Qingren.

Since the beginning of the 21st century, China’s electrolytic aluminum industry has developed rapidly. In 2017, China’s electrolytic aluminum production reached 32.27 million tons, and its production capacity has exceeded 40 million tons, ranking first in the world, with production accounting for 57% of the world total. At the same time, the environmental pollution problem of the electrolytic aluminum industry has been highly concerned by the state, industry and society. Overhaul slag is a typical hazardous solid waste discharged from electrolytic aluminum production. On average, for every ton of electrolytic aluminum produced, 20-30kg of overhaul slag will be produced, with an annual total discharge of millions of tons. Because the overhaul slag contains soluble fluoride and cyanide, which are highly toxic, if it is not disposed properly, it will be mixed with the rainwater into the river, infiltrated into the underground polluted surface water, groundwater and soil, which will cause great impact on the surrounding ecological environment, human health and the growth of animals and plants. Great harm. In March 2016, the Ministry of Environmental Protection’s new National Hazardous Waste List (2016 Ministry of Environmental Protection Order No. 39) has clearly stipulated that aluminum electrolytic cell overhaul slag belongs to Class T industrial hazardous waste. The harmless resource treatment of overhaul slag has become one of the major problems to be solved urgently in the electrolytic aluminum industry.

Zhengzhou Hongyue Environmental Protection Technology Co., Ltd., Hunan Zhongda Metallurgical Design Co., Ltd. and Zhengzhou University of Light Industry and other units, after more than ten years of research, experimentation and continuous exploration, and further optimized through industrial application, developed “acid-free leaching + The four-step process technology of oxidizing cyanide + calcium salt defluoridation + physical sedimentation can effectively remove the harmful substances in the overhaul slag. The treated materials can strictly meet the national emission standards and effectively solve the overhaul slag of the aluminum plant electrolyzer. Harmless handling of problems.

The results evaluation expert group unanimously determined that the “electrolytic aluminum overhaul slag wet acid-free treatment process and industrialization” technology developed by the project effectively solved the problem of harmless treatment of the toxic substances in the electrolytic cell of the aluminum plant; The reaction ratio is precisely controlled, which effectively improves the labor intensity and working environment of the workers, has high production efficiency, low material consumption and stable treatment effect; the project has small investment and low cost, and fundamentally solves the equipment and plant existing in the acid treatment process. Corrosion problems effectively improve the economics and safety of production. The project technology has promoted and built 11 production lines including Baotou Hope, Zhongfu Industry and Yunnan Defu Environmental Protection in China, realizing industrial application, good technology reproducibility, high maturity, application effect reaching environmental protection standards, and getting users. Recognition. The overall technology of the project results has reached the international advanced level.

Electrolytic aluminum overhaul slag harmless technology