126 results about "Metallurgical silicon" patented technology

The invention concerns a method for producing a medium purity silicon comprising: preparing, by carbothermic reduction of silica in a submerged arc-furnace a silicon with low boron content; refining the liquid silicon with oxygen or chlorine; treating the refined silicon under reduced pressure from 10 to 100 Pa with neutral gas injection; segregated solidification. The invention also concerns a medium purity silicon designed to serve as raw material for making silicon of electronic or voltaic quality, and having (in weight fractions): a total of impurities ranging between 100 and 400 ppm, with the content in metallic elements ranging between 30 and 300 ppm; a boron content from 1 to 10 ppm; a phosphorus / boron ratio ranging between 0.5 and 1.5.

The invention discloses a novel method for comprehensively treating waste mortar formed by processing photovoltaic cell crystalline silicon. Aiming to different physicochemical properties of four components of the waste mortar formed by processing photovoltaic cell crystalline silicon and under the condition of ensuring that Si micropowder is not subjected to a chemical reaction, PEG (Polyethylene Glycol) and iron are separated and recovered; SiC and Si binary sand is treated by adopting various treatment methods to obtain corresponding SiC and Si series products; the SiC and Si micropowder is hydraulically sorted or sorted by air current by utilizing the granularity difference and the density difference of the SiC micropowder and the Si micropowder in the binary sand to obtain SiC micropowder and Si miropowder; the Si miropowder is washed and purified with purified water and reagent-grade inorganic acid to obtain high-purity Si miropowder; the sorted Si miropowder is fed into an electrical furnace for melting and recasting to obtain a silicon cast ingot material; the binary sand is fed into the furnace for melting and recasting to obtain a metallurgical silicon cast ingot material and a Si and SiC mixed cast ingot material; a proper amount of carbon is fed into the binary sand to react and generate SiC; and SiC, Si and Fe ternary sand is fed into the electrical furnace for melting and recasting to obtain a silicoferrite material for metallurgy.

A fluidized bed reactor (FBR) for producing chlorosilane mixture, which has high contents of tri-chlorosilane (TCS), by hydro chlorination of metallurgical silicon (MGSI) and a method of producing high contents of TCS stably with the FBR is disclosed. A cooling jacket, which surrounds the lower reactor section, combined with inert initial charging material, which does not react with HCl during the reaction at a temperature of above 300° C. and pressure of above 5 bar, controls the extreme exothermal heat of the reaction. In addition to this, combination of an optimized gas distributor and a feeder that can feed the metallurgical silicon with accuracy of ±5% enabled to realize uniform temperature profile within the reaction zone within ±1 degree ° C. deviation at 350° C. of average reaction temperature and at 5 bar of reaction pressure.

The invention discloses a method for slagging, boron removal and purification of metalluragical silicon, comprising the following steps of: selecting a metalluragical silicon material, heating until the metalluragical silicon is completely melted into a silicon solution and adjusting the temperature of the silicon solution; then adding a ternary slagging agent; removing scum on the surface of the silicon solution by stirring and carrying out a heat-insulating reaction; and standing the silicon solution for casting and then obtaining polysilicon, wherein the content of B in the polysilicon meets the solar level requirement. According to the method, complicated blowing equipment can be avoided, the process equipment can be simplified and the cost can be reduced; and the method is convenient for industrial application.

The invention discloses a pickling impurity removal method for removing impurities after metallurgical silicon drawacharge and before melting purification. The method comprises the following steps: slowing down the cooling process of the drawacharge of the metallurgical silicon, smashing the cooled metallurgical silicon into silicon powder with certain granularity, and selecting a plurality of acids to carry out pickling operation on the silicon powder according to a certain sequence. The invention also discloses pickling impurity removal equipment, a metallurgical silicon purification methodand a metallurgical silicon purification system. In the invention, optimized cooling process and reasonable pickling sequence are adopted, and proper granularity and suitable temperature are selected,therefore, the pickling process flow is optimized to realize the optimal pickling effect, the content of Fe, Al, Ca, Mn, Ti, Ni and other metal impurities are effectively reduced, and the purification purpose is realized.

One embodiment of the present invention provides a heterojunction solar cell. The solar cell includes a metallurgical-grade Si (MG-Si) substrate, a layer of heavily doped crystalline-Si situated above the MG-Si substrate, a layer of lightly doped crystalline-Si situated above the heavily doped crystalline-Si layer, a backside ohmic-contact layer situated on the backside of the MG-Si substrate, a passivation layer situated above the heavily doped crystalline-Si layer, a layer of heavily doped amorphous Si (a-Si) situated above the passivation layer, a layer of transparent-conducting-oxide (TCO) situated above the heavily doped a-Si layer, and a front ohmic-contact electrode situated above the TCO layer.

The invention discloses a removing method of boron impurities in metallurgical silicon, comprising the following steps: immersing the metallurgical silicon powder into acid for 6 hours to 48 hours to carry out acid cleaning, washing the metallurgical silicon powder, drying the metallurgical silicon powder, putting the metallurgical silicon powder subjected to the acid cleaning, the washing and the drying into a reactor, heating the metallurgical silicon powder to the temperature of 300 DEG C-700 DEG C, introducing oxidizing gas to carry out an oxidizing reaction for 6 hours to 72 hours, immersing the metallurgical silicon powder which is heated and oxidized into water or acid for 1 hour to 6 hours, washing the metallurgical silicon powder, and baking the metallurgical silicon powder which is immersed and washed for 6 hours to 24 hours at the temperature of 100 DEG C-300 DEG C. With the purification process of the metallurgical silicon of the invention, because the purification is completed at lower temperature, the operation is easier and simpler, the purification cost is also reduced. Thus, high quality raw materials are provided for later processes so that needs of producing solar-grade polycrystalline silicon at low cost are met.

The invention belongs to the technical field of metallurgical purification, and particularly relates to a polysilicon purification method. The method comprises the following steps: performing alloying smelting on metal and metallurgical silicon to obtain a silicon alloy; adding basic slagging agent into the silicon alloy used as a raw material, slagging, smelting, and purifying; and finally, keeping the temperature of the melt, cooling, and separating according to density difference to obtain high-purity silicon, the slagging agent and the silicon alloy, wherein the slagging agent and the silicon alloy can be recovered and used repeatedly. By adding a small amount of metal element into the metallurgical silicon, the metal element and the silicon can be formed into the alloy melt, thus effectively lowering the smelting temperature in the slagging and purifying process and reducing the crucible loss; in the cooling process, impurities have fractional condensation effect between the silicon and the alloy melt, thus effectively lowering the boron impurity content in the primary silicon and improving the purifying effect; and finally, based on the density difference among the silicon, the alloy and the slagging agent, the three phases are separated, thus obtaining the high-purity polysilicon, ensuring that the silicon alloy and the slagging agent can be used repeatedly, and avoiding the reagent consumption and alloy element loss in the subsequent acid washing and purifying process.

A reactor for hydrogenation of a silicon tetrahalide and metallurgical grade silicon to trihalosilane includes a bed of metallurgical silicon particles, one or more gas entry ports, one or more solids entry ports, one or more solids drains and one or more ports for removing the trihalosilane from the reactor. Fresh surfaces are generated on the bed particles by internal grinding and abrasion as a result of entraining feed silicon particles in a silicon tetrahalide / hydrogen feed stream entering the reactor and impinging that stream on the bed of silicon particles. This has the advantages of higher yield of the trihalosilane, higher burnup rate of the MGS, removal of spent MGS as a fine dust carryover in the trihalosilane effluent leaving the reactor and longer times between shutdowns for bed removal.