China News Service, Guiyang, November 27 (Liu Meiling) "Compared with the traditional technology, the'medium and low-grade phosphate rock high-efficiency, clean, comprehensive utilization and beneficiation integrated technology' is a subversive change, improving the quality and reducing the quantity or avoiding the production of phosphogypsum from the source." On the 27th, the "black technology" introduced to reporters by Zhang Qin, a researcher at the Guizhou Research Institute of Chemical Industry, was the latest scientific research result released by the institute.

  Phosphogypsum is a solid by-product produced in the production of wet-process phosphoric acid by phosphoric chemical companies. Data shows that every 1 ton of phosphoric acid produced will by-produce 4 to 5 tons of phosphogypsum. The actual utilization rate of phosphogypsum in China is currently about 40%, and the rest Through stockpiling, however, a large amount of stockpiling will bring huge environmental risks.

The high-efficiency comprehensive utilization technology of low- and medium-grade phosphate rock of the Guizhou Research Institute of Chemical Industry won the second prize of the Basic Research Achievements of the Chinese Society of Chemical Industry in September 2021.

Photo courtesy of the interviewee

  "For the sustainable development of the phosphate chemical industry, the production and effective use of phosphogypsum has become the primary issue that must be solved." Zhang Qin said that China's phosphate rock reserves rank second in the world, and about 80% of them are medium and low grades that cannot be directly utilized. Phosphate rock.

  At present, the domestic medium and low-grade phosphate ore beneficiation process basically uses physical beneficiation, which not only has a greater impact on the environment, but also has a higher cost.

It is a common bottleneck problem encountered in the development of China's basic phosphorus chemical industry.

  In order to fundamentally solve the key common problems in the phosphorus chemical industry, the scientific research team of the Guizhou Provincial Research Institute of Chemical Industry has innovated and developed the "integrated technology for the efficient, clean and comprehensive utilization of low- and medium-grade phosphate ore beneficiation" to solve the generation of phosphate tailings and the recovery rate of phosphorus from the source. The problems of low phosphate concentration and low quality of the obtained phosphate concentrate greatly improve the formation and treatment conditions of phosphogypsum, and directly obtain high-quality phosphogypsum.

  This technology also solves the worldwide problem of separation of acid-insoluble matter in the extraction of phosphoric acid by nitric acid method.

In addition, high-quality phosphate concentrates can be obtained through this technology. For example, it can be used to produce phosphoric acid by the traditional sulfuric acid method, which can reduce the production of phosphogypsum and improve its quality.

When used in the production of phosphoric acid by the nitric acid method, the production of phosphogypsum can be prevented from the source.

Through this technology, the associated magnesium in the phosphate rock can be separated and produced into magnesium hydroxide, which opens up a new way for the development of the magnesium industry of the phosphate rock resources and greatly increases the added value of the phosphate rock resources.

Guizhou Phosphate Group-Chuanyandong mining area using phosphogypsum ecological management mine comparison chart.

Photo courtesy of the interviewee

  "The new technology we have developed has 6 innovations and has completely independent intellectual property rights." Zhang Qin said that the application of this technology will create a new type of modern phosphorous chemical enterprise with neither tailings slag nor phosphogypsum slag.

  In 2017, Guizhou Provincial Research Institute of Chemical Industry and Shanghai Shengyuan Group cooperated to establish Guizhou Shengyuan New Materials Co., Ltd., and established a set of "3,000 tons/year low- and medium-grade phosphorus in Languan Township, Weng'an County, Qiannan Prefecture, Guizhou Province New ore dressing test device for ore and phosphate tailings", to carry out test work.

  After experiments, in June 2018, the China Chemical Industry Society organized domestic authoritative experts to evaluate the scientific and technological achievements of the "Medium and Low Grade Phosphate Ore Efficient and Clean Comprehensive Utilization of Beneficiation Integrated Technology" and "Phosphate Tailings Efficient and Clean Comprehensive Utilization Technology". The evaluation conclusions are as follows: "The technological achievements have reached the leading domestic level."

  In October 2020, the integrated technology for the efficient and clean utilization of low- and medium-grade phosphate ore beneficiation of the Guizhou Research Institute of Chemical Industry won the 2018-2020 Inorganic Chemical Technology Progress Award.

  In September 2021, the high-efficiency comprehensive utilization technology of low- and medium-grade phosphate rock from the Guizhou Research Institute of Chemical Industry won the second prize of the Basic Research Achievements of the Chinese Society of Chemical Industry.

  At present, this technology project has been included in the "14th Five-Year Plan" of Guizhou Province, and the scientific research team of this technology has signed a framework cooperation agreement with Hubei Yihua Group.

  The problems caused by phosphogypsum require both symptoms and root causes. Guizhou currently produces more than 10 million tons of phosphogypsum each year. The large-scale stock and production volume have put tremendous pressure on enterprise development and the ecological environment.

  To this end, the Guizhou Provincial Research Institute of Chemical Industry has introduced microbial ecological treatment and restoration technology, using the physiological characteristics of microorganisms to treat phosphogypsum harmlessly, so as to achieve mine restoration, comprehensive land management and ecological green resource applications.

  Chen Wenxing, Chief Engineer of the Guizhou Provincial Research Institute of Chemical Industry, said: “After the extensive application of the microbial green ecological treatment and restoration technology system, it can realize the'waste treatment with waste', realize the coordinated advancement of high-quality economic development and high-level protection of the ecological environment, and promote the high level of phosphorus chemical industry. Quality continues to develop."

  Microbial green ecological treatment and restoration technology has been successfully demonstrated in the treatment of phosphogypsum and the restoration of mines in Guizhou Phosphate Group's mining area.

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