As a strategic resource, fluorine is highly valued by the country. The comprehensive utilization of fluorine should implement the three principles of circular economy, promote the production of “green products†in practice, reduce the pollution caused by the use of products by downstream customers, track the whereabouts of products, and carefully study the whereabouts of fluorine and its recycling.
China's fluorine chemical industry has more than 50 years of development history. Before the 1980s, domestic fluoride production processes were simple, equipment was backward, and product varieties were relatively simple. After the 1980s, China made great progress in the research and development of fluoride products. Fluoride has become very important in the national economy. Chemical Products. With the new demands for fluoride in industries such as metallurgy, chemical industry, machinery, optical instruments, and electronics, the world's inorganic fluorine chemical products have grown to more than 1,000 kinds, and China has more than 100 kinds of fluorine chemical products in mass production.
Fluoride resources 1. The basic situation of fluorine resources.
Fluorite reserves are limited. At present, fluorspar is the main source of fluorine. The world reserves of fluorspar are about 600 million tons, and China's reserves account for about 54%. The world consumes 4.6 million tons of fluorite every year, of which 2.6 million tons come from China. In order to protect this strategic resource, China has now restricted mining and exports.
Phosphorus ore contains a lot of fluoride resources. The world's phosphate ore reserves are about 60 billion tons, and the fluorine content in phosphate ore is about 2% to 4%. The fluorine associated with phosphate ore accounts for more than 87% of the world's fluorine reserves, which is far greater than that of fluorite. Currently, there are only 800-140 million tons of fluorine in the phosphate rock currently having actual mining value, which is equivalent to 1.6-200 million tons of fluorspar fluorine content.
2. The status of the use of fluorine resources.
(1) The status of resource utilization is irrational. At present, China's fluorine chemical production mainly uses fluorspar as raw material. This kind of resource utilization is unreasonable. There is no effective resource for the development and utilization of the fluorine resources in the largest phosphate reserves. It is a resource issue that needs to be solved.
(2) The results of fluorine resource utilization of polyfluoride. In 1999, relying on technological advancement and innovation, Duoduduo Company successfully developed the production technology of "producing high-quality white carbon black from cryolite-produced cryolite" around the comprehensive utilization of the by-product fluorine resources of phosphate fertilizers. This technology uses phosphate by-product sodium fluorosilicate as raw material to produce high molecular ratio cryolite, creating a new path for fluoride production of electrolytic aluminum in China. It not only opens up new fluorine resources, but also solves long-term problems and constraints. The "three wastes" pollution problem in the development of phosphate fertilizers in China has also saved the national strategic resource, fluorite. This technology was rated by the former State Development Planning Commission as a "National High-tech Industrialization Demonstration Project", and it was given 8 million yuan in treasury bond funds.
The company continued to commit itself to the comprehensive development of phosphate production by-product fluorine and the use of fluorosilicic acid to produce a series of fluoride products. In 2007, the company's “Fluorine Resources Comprehensive Utilization Project†was included in the national resource conservation and environmental protection bonds in 2007. The project received financial support of 4.8 million yuan from the country.
3. Analysis and outlook.
(1) Reasons for the failure of the use of the by-product fluorine in phosphate fertilizers. The first is institutional reasons. The traditional planned economy system prevented pilot enterprises from obtaining raw materials (such as aluminum hydroxide) with reasonable prices from the non-ferrous metals industry. At the time, the fluoride plant was mostly set up for aluminum plants. It was difficult for pilot companies to enter the aluminum industry; the second was the process. On the reason. All countries’ production processes have been tested in China, and China has become a testing ground for foreign technology. Although these technologies were very advanced at the time, domestic companies did not digest the innovative capacity they had absorbed, and they basically did not localize them; the third issue was equipment. Some companies can't find a suitable matching device even though the process is open. Fourth, there is not enough awareness of environmental protection.
(2) Outlook. The development of a recycling economy of fluoric resources will help protect and save the country’s important strategic resource, fluorite, which will help develop and utilize new “fluorine†resources, which are by-products of phosphate fertilizers, and provide a strong resource guarantee for the sustainable development of fluorinated workers in China. Facilitate the advancement of technological advancement and independent innovation in the fluorine chemical industry, especially the development of the use of the by-product fluorine production of phosphate fertilizers to produce fluorine chemical products. While promoting the progress of the fluorine chemical industry, the fluorine chemical industry will develop a recycling economy and promote the development of green chemical technologies. may.
Reduction in the use of fluorine resources Polymer than cryolite. At present, domestic cryolite products can be divided into two major categories: macromolecular cryolite and common cryolite. The macromolecular cryolite process uses sodium fluorosilicate as raw material to produce cryolite products in an alkaline environment; common cryolite processes The hydrofluoric acid produced from fluorite is used as raw material to produce cryolite products in an acidic environment.
2. Anhydrous aluminum fluoride. At present, domestic aluminum fluoride products can be divided into three categories: anhydrous aluminum fluoride, dry aluminum fluoride, and wet aluminum fluoride. Anhydrous aluminum fluoride technology uses anhydrous hydrogen fluoride (above 99.9%) The raw materials are produced by gas-solid reaction with aluminum hydroxide to produce aluminum fluoride products; the dry aluminum fluoride process is mainly produced by the unpurified hydrogen fluoride gas produced from fluorite as raw material and aluminum hydroxide undergoes gas-solid reaction to produce aluminum fluoride products; The aluminum fluoride process is based on the use of hydrofluoric acid produced from fluorite as raw material and aluminum hydroxide for liquid-solid reaction to produce aluminum fluoride products.
Taking the domestic electrolytic aluminum output of 12.8 million tons in 2007 as an example, anhydrous aluminum fluoride is used instead of the original wet aluminum fluoride, and the country will reduce emissions of 20,000 tons or more per year.
Reuse of fluorine resources 1. Electrolytic aluminum industry fluorine recycling work. In 2007, the global output of electrolytic aluminum reached 36 million tons (including China's 12.8 million tons). In 2008, the global output of electrolytic aluminum is expected to reach 39 million tons (including 14.5 million tons in China), calculated as 28 kilograms of fluoride per ton of aluminum consumed, both at home and abroad. The consumption of fluoride salt in the market was 10l tons in 2007 and 1.09 million tons in 2008.
Fluoride salts are theoretically not consumed as a flux for electrolytic aluminum. Analysing the electrolytic aluminum production process, the main destination of fluorine is the volatilization of fluorine-containing gas, absorption by electrolytic cells,
Electrolyte inventory and electrolyte loss during electrolysis.
2. Aluminum industry and other industries fluorine recycling work. The use of fluorine-containing electrolytes, which are by-products of the aluminum industry, as raw materials for the production of cryolite, allows the recycling of fluorine resources and produces good economic and social benefits.
The surface of the aluminum profile is treated with ammonium bifluoride to obtain the ammonium fluoroaluminate residue. Ammonium fluoroaluminate can produce ammonium bifluoride as a byproduct of aluminum fluoride. This process is more in line with the concept of circular economy.
Technical progress and suggestions Technological progress.
(1) The pilot test of “the production of hydrofluoric acid using fluosilicic acid produced by phosphate fertilizer†jointly developed by China's Yuntianhua Group Sanhuan Co., Ltd. and Tianjin Chemical Research and Design Institute was completed before the industrialization work began.
(2) Guizhou Hongfu Co., Ltd. has signed a cooperation agreement with Switzerland Daiwei Co., Ltd. for the introduction of technology for the production of hydrofluoric acid from the use of phosphoric acid by-product fluorosilicic acid. It has been successfully implemented and has become the world's first large-scale device for the production of hydrofluoric acid from the production of fluorosilicic acid by the use of phosphate fertilizer, which has a strong demonstration effect.
(3) Fluoride's efforts. Based on the successful implementation of the production of high-quality white carbon black from sodium cryolite produced by sodium fluorosilicate method, the company carried out research on aluminum fluoride and series of fluoride salts made from fluorosilicic acid. Some of the processes and products are being industrialized and actively participated in the Yunnan fluorine. Development of resources and pilot work.
The company presided over the revision of cryolite, hydrofluoric acid, anhydrous hydrogen fluoride national standards, presided over the development of lithium fluoride national standards, is presiding over the development of 16 general chemical industry standards, production of cryolite, aluminum fluoride national instrument analysis standard samples, Established China's fluoride industry sector. A national accredited laboratory.
The company follows the concept of “using fluorine for the benefit of mankind†and aims to “create an inorganic fluorine chemical industrial base in Chinaâ€. Through technological innovation and management innovation, the company has scaled the aluminum fluoride products and refined the electronic-grade fluoride products. Other inorganic fluoride series.
2. Conclusion and suggestion. The fluorine-silicon resources of China's industrial by-products can provide sufficient fluorine resources for the fluorine chemical industry. The technological development of the conversion of fluorosilicic acid to hydrofluoric acid has achieved a substantial breakthrough. Entering the implementation stage, the production of hydrofluoric acid using by-product fluorosilicic acid has obvious economic advantages. Considering the development of silicon series products, the benefits are even more obvious.
The comprehensive utilization of fluorine involves many industries such as phosphate fertilizers, fluorinated chemicals, and non-ferrous metals, and the relevant national departments and various industry associations should further play their roles in strengthening the planning and management control of fluorine resources and making full use of such advantageous enterprises and research institutes as phosphorus, fluorine and silicon chemicals. The strengths of research and engineering design, collaboration and cooperation, improve resource utilization at both the elemental cycle and process engineering levels.
Accelerate economic restructuring and optimize regional distribution, and encourage the development of a recycling economy of fluorine resources. Through the adjustment of industrial structure, it is necessary to limit the elimination of backward technologies, equipment, and enterprises that waste resources and pollute the environment. Encourage the use of phosphate fertilizer by-products to develop recycling projects of fluorine resources, especially through the establishment of a resource-saving and comprehensive utilization type of industrial structure to further increase the efficiency of the use of fluorine resources.