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CN-118026182-B - Method for treating polycrystalline silicon and monocrystalline silicon waste

CN118026182BCN 118026182 BCN118026182 BCN 118026182BCN-118026182-B

Abstract

The invention relates to a method for treating polycrystalline silicon and monocrystalline silicon waste, belonging to the field of recycling of waste materials. The invention provides a method for treating polycrystalline silicon and monocrystalline silicon waste, which comprises the steps of carrying out vacuum filtration on monocrystalline silicon and polycrystalline silicon cutting waste slurry, mixing the monocrystalline silicon and polycrystalline silicon cutting waste slurry with 40-50% of electrolytic manganese anode slime TMn after filter pressing, preheating for dehydration, further heating to obtain a heated material, carrying out reduction roasting on the heated material in a reducing atmosphere, adding 1.5-2% of reducing agent, heating to a molten state through an electrode, obtaining slag which is high manganese slag after heating, and carrying out ingot casting on silicon water discharged after heating to obtain crude silicon. The method can effectively recover the polycrystalline silicon and the monocrystalline silicon waste, treat the electrolytic manganese anode slime and comprehensively utilize the two wastes, effectively solve the long-term pollution of the cutting waste and the electrolytic manganese anode slime, and improve the utilization rate of mineral resources.

Inventors

  • Dong Mangui
  • Lai jiaxing
  • NING GUODONG

Assignees

  • 上海逢石科技有限公司

Dates

Publication Date
20260505
Application Date
20240307

Claims (4)

  1. 1. A method for treating polycrystalline silicon and monocrystalline silicon waste is characterized by comprising the following steps: (1) Vacuum filtering monocrystalline silicon and polycrystalline silicon cutting waste slurry, and mixing the monocrystalline silicon and polycrystalline silicon cutting waste slurry with 40% -50% of electrolytic manganese anode slime TMn after press filtration to obtain a mixed raw material, wherein the water content of the mixed raw material is 7% -10%, and the ratio of the monocrystalline silicon and polycrystalline silicon cutting waste slurry to the electrolytic manganese anode slime in the mixed raw material is 1:1; (2) Preheating and dehydrating the mixed raw materials, and further heating to obtain a heated material, wherein the preheating temperature is 300-350 ℃ and the heating temperature is 850-950 ℃; (3) Placing the heated material in a reducing atmosphere, and carrying out reduction roasting at 700-780 ℃ for 1-1.5 hours to obtain a reduced material; (4) Adding 1.5% -2% of reducing agent into the reduced material, heating to a molten state through an electrode, wherein the temperature of a molten pool is 1700-1800 ℃, obtaining slag which is high manganese slag after heating, and casting ingot by using silicon water discharged after heating to obtain crude silicon.
  2. 2. The method of treating polycrystalline silicon and monocrystalline silicon waste as set forth in claim 1, wherein the reducing atmosphere in the step (3) is CO, H 2 or a mixture of both.
  3. 3. The method for treating waste materials of polysilicon and single crystal silicon as set forth in claim 1, wherein the reducing agent in the step (4) is low sulfur coal, the fixed carbon of the low sulfur coal is not less than 85%, and the granularity is 10-25mm.
  4. 4. The method for treating waste materials of polysilicon and monocrystalline silicon as set forth in claim 1, wherein the flue gas generated in the step (4) is returned to the suspension roasting furnace for waste heat recovery, and the flue gas of the suspension magnetizing roasting furnace is discharged after denitration and desulfurization.

Description

Method for treating polycrystalline silicon and monocrystalline silicon waste Technical Field The invention belongs to the field of recycling of waste materials, and particularly relates to a method for treating polycrystalline silicon and monocrystalline silicon waste. Background Silicon is mainly used for manufacturing high-purity semiconductors, high-temperature resistant materials, optical fiber communication materials, organosilicon compounds, alloys and the like. With the rapid growth of the semiconductor industry and photovoltaics, the demand for monocrystalline and polycrystalline silicon is continually increasing. The monocrystalline silicon wafer is a square wafer or an octagonal wafer formed by cutting a monocrystalline silicon rod, is commonly called as a silicon wafer in the industry, is one of basic main functional materials for manufacturing integrated circuits due to the advantages of higher precision, higher surface quality and the like, and is mainly applied to the aspects of manufacturing solar cell modules, high-power rectifiers, high-power transistors, diodes, switching devices and the like. Polysilicon can be used as a raw material for drawing single crystal silicon, and is also applied to semiconductors and solar cells. According to different purity requirements, polysilicon is divided into an electronic grade and a solar grade, and the demand of the solar cell for the polysilicon is rapidly increased along with the rapid development of the photovoltaic industry, and the productivity is continuously increased. A large amount of dangerous waste polycrystalline silicon and monocrystalline silicon can be generated in the process of manufacturing polycrystalline silicon and monocrystalline silicon, a large amount of silicon powder waste can be generated mainly in the process of cutting silicon wafers, about 50% of crystalline silicon can be lost in the form of silicon powder in the actual processing process, and the waste usually contains various harmful substances, such as metal impurities of aluminum, copper, iron and the like, and reasonable treatment is needed. At present, the treatment modes of waste paddles generated by cutting at home and abroad mainly comprise a physical flotation method and an acid or alkali chemical treatment method, but the overall relative process flow is complex, the production cost is higher, and industrialization is difficult. Disclosure of Invention Aiming at the problems existing in the prior art of recycling cutting waste slurry, the invention provides a method for treating polycrystalline silicon and monocrystalline silicon waste, which realizes recycling of the silicon waste through a suspension magnetization roasting-submerged arc furnace and achieves the effect of recycling resources with low cost. A method of treating polycrystalline silicon and monocrystalline silicon waste, comprising the steps of: (1) Vacuum filtering monocrystalline silicon and polycrystalline silicon cutting waste slurry, and mixing with 40-50% of electrolytic manganese anode slime TMn after filter pressing to obtain mixed raw materials; (2) Preheating and dehydrating the mixed raw materials, and further heating to obtain heated materials; (3) Placing the heated material in a reducing atmosphere, and carrying out reduction roasting at 700-780 ℃ for 1-1.5 hours to obtain a reduced material; (4) Adding 1.5% -2% of reducing agent into the reduced material, heating to a molten state through an electrode, wherein the temperature of a molten pool is 1700-1800 ℃, obtaining slag which is high manganese slag after heating, and casting ingot by using silicon water discharged after heating to obtain crude silicon. Further, the mixed raw material in the step (1) contains 7-10% of water, and the ratio of the monocrystalline silicon and polycrystalline silicon cutting waste slurry to the electrolytic manganese anode slime in the mixed raw material is 1:1. Further, the preheating temperature in the step (2) is 300-350 ℃, and the heating temperature is 850-950 ℃. Further, the reducing atmosphere in the step (3) is CO, H 2 or a mixed gas of the CO and the H 2, and the reducing atmosphere accounts for 45-55%. Further, the reducing agent in the step (4) is low-sulfur coal, the fixed carbon of the low-sulfur coal is more than or equal to 85%, and the granularity is 10-25mm. Further, the flue gas generated in the step (4) returns to the suspension roasting furnace for waste heat recovery, and the flue gas of the suspension magnetizing roasting furnace is discharged after denitration and desulfurization. Compared with the prior art, the method has the beneficial effects that the method can effectively recycle the polycrystalline silicon and monocrystalline silicon waste, simultaneously treat the electrolytic manganese anode slime to achieve the comprehensive utilization of the two wastes, and has simple and feasible process, mature equipment and easy realization of industrialization. The method can