Silicon metal 3303: industrial silicon, also known as silicon metal, is a trading name that appeared in the mid-1960s. Silicon metal is a product smelted by silica and carbonaceous reducing agent in a submerged arc furnace. The content of the main component silicon is about 98% (in recent years, the silicon content of 99.99% is also listed in metal silicon), and the rest of the impurities for iron, aluminum, calcium and so on. According to the content of iron, aluminum and calcium in silicon metal, The silicon metal can be divided into 553, 441, 411, 421, 3303, 3305, 2202, 2502, 1501, 1101, and other different grades. Additional products of silicon metal include micro-silica fume, edge-skin silicon, black-skin silicon, metallic silicon slag, etc. Among them, micro-silica fume is also called silica fume, which is widely used in refractory materials and concrete industries.
Industrial silicon material is an extremely important intermediate product in the silicon product industry chain. It is the main raw material for the manufacture of silicon polishing wafers, solar cells and high-purity silicon products. It is the most basic raw material for the information industry and new energy industry. It can also be said that 3303 Silicon metal has become a basic pillar industry in the information age. Therefore, improving product quality, removing impurities from industrial silicon products, and preparing high-purity 3303 metal silicon are issues that researchers are generally concerned about. At present, the most common impurity removal method in industrial silicon plants is to carry out out-of-furnace refining of industrial silicon in a ladle. However, the injection of refining gas and the addition of a large amount of slagging agent can significantly reduce the temperature of industrial silicon melt. Therefore, it is not realistic to use the waste heat of industrial silicon melt to carry out out-of-furnace refining for a long time, which restricts the development of industrial silicon out-of-furnace refining technology and the further improvement of industrial silicon product quality. metal silicon 3303 often has the disadvantage of low purity. The low purity here is not caused by too many impurities, but is caused by incomplete purification.
The method of refining and purifying silicon metal 3303 outside the furnace solves the problems of low heat utilization rate and low purity of the prepared industrial silicon. Include the following steps:
Step 1.During the release of silicon melt, the refining gas is continuously pumped into the ladle, and then the silicon melt in the ore heat furnace is released into the ladle. At the same time, the silicon water in the ladle is heated and kept warm for the first time.
Step 2: After the initial temperature rise, add a refining agent to the ladle, carry out air blowing outside the furnace, and slag refining;
Step 3: Reheat and keep the remaining silicon water in the ladle;
Step 4: After heating up again, adjust the flow rate of the refining gas, and then add refining agent to the ladle to carry out air blowing outside the furnace and slag refining;
Step 5: After the refining outside the furnace is completed, the slag and silicon are separated, and then poured to obtain high-purity metal silicon 3303 .