Abstract:
A process for removing aluminum and other metal chlorides from liquid chlorosilanes with the steps of: introducing a source of seed into a source of impure liquid chlorosilanes, initiating the crystallization of aluminum and other metal chlorides on the seed from the liquid chlorosilanes in a first agitated vessel, passing the resulting mixture of liquid and solids through a cooler into a second agitated vessel for additional crystallization, transferring the resulting mixture of liquid and solids into a solids removal device, transferring the liquid with reduced solids content to a further process or vessel and transferring the liquid with high solids content into a waste concentration device, passing the resulting liquid with reduced solids content to a further process or vessel and passing the resultant liquid with very high solids content to a waste storage vessel with agitation.
Abstract:
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.
Abstract:
A gas-solids contactor modification is described which provides for starting or restarting the gas flow to the gas-solids contactor when it is filled with solid particles while preventing the solids from entering and blocking one or more gas inlets which have diameters greater than the solid particle diameters. The apparatus modification comprises a gas plenum and one or more chambers within the gas plenum located between the contactor inlet and the gas inlet. The wall of the chamber has multiple passageways therethrough that are smaller in diameter than the majority of the bed particles. Gas feed to the plenum must pass through the passageways in the chamber walls before entering the contactor. In one embodiment the total open area of the passageways is at least as large as the cross-sectional area of the gas inlet and the inlet to the contactor.
Abstract:
A process for removing aluminum and other metal chlorides from liquid chlorosilanes with the steps of: introducing a source of seed into a source of impure liquid chlorosilanes, initiating the crystallization of aluminum and other metal chlorides on the seed from the liquid chlorosilanes in a first agitated vessel, passing the resulting mixture of liquid and solids through a cooler into a second agitated vessel for additional crystallization, transferring the resulting mixture of liquid and solids into a solids removal device, transferring the liquid with reduced solids content to a further process or vessel and transferring the liquid with high solids content into a waste concentration device, passing the resulting liquid with reduced solids content to a further process or vessel and passing the resultant liquid with very high solids content to a waste storage vessel with agitation.
Abstract:
A process for high temperature hydrolysis of halosilanes and halides with the steps of: providing a bed of fluidized particulate material heated to at least 300° C., injecting steam and an excess of reactants into the reactor, removing solid waste from a bottom outlet, removing the effluent gases through a solids removal device such as a cyclone, condensing and separating some of the unreacted waste from the effluent gas in a distillation column and sending the effluent gases containing hydrogen and hydrogen chloride to a compressor. In a preferred embodiment the reactants contain at least one water reactive halide, selected from the group halosilane, organohalosilane, aluminum halide, titanium halide, boron halide, manganese halide, copper halide, iron halide, chromium halide, nickel halide, indium halide, gallium halide and phosphorus halide and where the halide content is selected from chlorine, bromine and iodine.