Recently, Prof. Liu Wanyi of the School of Chemistry and Chemical Engineering of Ningxia University took notes when representing representatives of more than 60 ferroalloy production enterprises in Ningxia: The annual production capacity of ferroalloys in the district is 1.2 million tons, and approximately 30,000 tons of microsilica is produced. If the content of silicon dioxide in microsilica reaches more than 92%, and then remove impurities, with the current domestic market conditions, the price per ton can reach 2,000 yuan, and the annual production value is 60 million yuan. After further purification, it will be sold to foreign countries. higher.
Prof. Liu Wanyi went on to say with regret that he did not understand why some ferroalloy companies threw it as waste.
Later, someone told Professor Liu Wanyi that it was not the enterprise that did not want to recover the silica fume but that it could not be recycled.
The ferroalloy industry knows that when the submerged arc furnace produces ferrosilicon and industrial silicon, the dust emitted from the flue gas will cause extremely serious atmospheric pollution. Iron alloy soot particles are also the leading cause of high incidence of lung cancer. However, smoke dust is not useless. If they are resourced, recycling a kind of semi-encrypted silica fume known as a magic material abroad can achieve a win-win result of economic benefits and environmental benefits. However, Ningxia Rongsheng Ferroalloy Group Co., Ltd. engineer Lan Lanjun said: “Since 85% of pure silicon powder costs 1 ton, it costs 500 yuan, while the operating cost of the recovery unit is 700 yuan per ton. The high cost has forced the recycling of ferroalloy companies in the region. The equipment is basically shut down. The company invested 32 million yuan in 2003, installed a dust recycling device, and can recover 5,000 tons of silicon micropowder every year because the purity of the produced silicon micropowder is 85% due to the constraints of the backward recycling process. Between 90%, the funds have not been recovered after 3 years.""
Some manufacturers of ferroalloys equipped with recovery devices only turned on the machines for inspections and smoked dust in the evening. This not only caused the loss of blank silica fume, but also caused pollution in the surrounding environment. "Ningxia Hui Autonomous Region Environmental Monitoring Brigade, said Kong Lingbin.
According to an industry insider, more than 20 of the more than 60 ferroalloy manufacturing companies in the region could not continue to maintain the recovery of silicon micropowders, and the rest was barely operating. Only Helanshan Ferroalloy Co., Ltd. has recovered better.
In addition, the promotion of Blank Silica Fume in the domestic market has also reduced the enthusiasm of corporate recycling.
Rong Shengjun, an engineer of Rongsheng Group, explained that the entire building materials industry in China has blind spots in its understanding of silicon micropowders, and most companies do not understand their market potential and therefore use very little. The silicon micropowders produced in Ningxia are also used only in large-scale projects such as the Three Gorges Dam and the Qinghai-Tibet Highway. In developed countries such as Japan and the United States, some products of the construction industry must add silicon micropowders in order to increase flexibility, so the market for silicon micropowders is very large in foreign countries. Since the production of silicon micropowders in most ferroalloy production plants in Ningxia is difficult to scale, foreign exports are difficult to do. Therefore, although the international market price of silicon micropowders with purity above 98% reaches US$8,000 per ton, most companies in Ningxia are currently producing. The silicon micropowder is difficult to export separately, but it can only be acquired by Norway's Elkem Group at a low price, and it will enter the international market.
“Shizuishan City is one of the main distribution areas of silicon raw material resources in China. Silicon micropowder resources are abundant. In order to recycle silicon micropowder into industry, it is necessary to solve the contradiction between product recovery and environmental protection costs. The government’s recovery of silicon micropowders cannot be blindly focused. In order to force enterprises to solve the problem of environmental protection and improve product quality, they should participate in the promotion of silicon micropowder applications, increase the market for silicon micropowder sales, and find a way for the recycling of silicon micropowder from ferroalloy companies. The enthusiasm for recycling microsilica," Professor Liu Wanyi concluded at the end of his lecture.
Chengdu Rongjian Engineering Materials Co.Ltd
