Gas separation by semi-permeable membranes
AssigneeUnion Carbide Chemicals and Plastics Company Inc.
InventorsShan-Tao Hsieh, George E. Keller, II
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Abstract
A method is disclosed for separating gaseous silicon compounds from hydrogen and/or hydracids. Specifically, the method comprises the utilization of semi-permeable membranes for such gaseous separation. Particularly preferred is a composite membrane comprised of a coating separation layer of sulfonated polysulfone and a support layer of polysulfone. Mixtures of hydrogen and silane are particularly suitable for being separated by means of composite membrane separation.
Claims74
A method for separating at least a first gas selected from the group consisting of H.sub.2, HX and mixtures thereof contained in a gaseous mixture from at least a second gas selected from the group consisting of SiX.sub.a H.sub.b and mixtures thereof, where X =a halogen ion,
- a =0 to 4,
- b =0 to 4,
- a +b =4
- contained in said gaseous mixture which comprises contacting the gaseous mixture with one surface of a semi-permeable membrane which exhibits selective permeation of the at least first gas over that of the at least second gas, and removing from the vicinity of the opposite surface of the semi-permeable membrane a permeate having a concentration of the at least first gas which is greater than the concentration of the at least first gas in the gaseous mixture.
A method of separating hydrogen from silane contained in a gaseous mixture which comprises contacting the gaseous mixture with one surface of a semi-permeable membrane which exhibits selective permeation for the hydrogen over that of the silane and removing from the vicinity of the opposite surface of the semi permeable membrane a permeate having a concentration of hydrogen which is greater than the hydrogen concentration in the gaseous feed mixture.
A method of separating hydrogen from trichlorosilane contained in a gaseous mixture which comprises contacting the gaseous mixture with one surface of a semi-permeable membrane which exhibits selective permeation for the hydrogen over that of the trichlorosilane and removing from the vicinity of the opposite surface of the semi-permeable membrane a permeate having a concentration of hydrogen which is greater than the hydrogen concentration in the gaseous feed mixture.
A process for producing a semiconductor silicon metal from a chlorosilane selected from the group consisting of trichlorosilane, dichlorosilane and mixtures thereof, which comprises:
- (a) providing the chlorosilane in admixture with hydrogen gas in a reaction zone having a temperature sufficient to effect reduction and decomposition of said chlorosilane to silicon metal on a deposition surface;
- and then
- (b) contacting exhaust gases leaving the reaction zone comprised of at least unreacted chlorosilanes, hydrogen, and by product hydrogen chloride with a semi-permeable membrane separator which exhibits selective permeation of the hydrogen and hydrogen chloride over the chlorosilanes, to produce a permeate having a concentration of hydrogen and hydrogen chloride which is greater than the concentration of hydrogen and hydrogen chloride in the exhaust gases, and a raffinate having a concentration of chlorosilanes which is greater than the concentration of such chlorosilanes in the exhaust gases.
A process for producing a semiconductor silicon metal from silane which comprises:
- (a) providing the silane in admixture with hydrogen gas in a reaction zone having a temperature sufficient to effect reduction and decomposition of said silane to silicon metal on a deposition surface;
- and then
- (b) contacting exhaust gases leaving the reaction zone comprised of at least unreacted silane and hydrogen with a semi-permeable membrane separator which exhibits selective permeation of the hydrogen over the silane to produce a permeate having a concentration of hydrogen which is greater than the concentration of hydrogen in the exhaust gases and a raffinate having a concentration of silane which is greater than the concentration of such silane in the exhaust gases.
Dependencies are inferred from the claim text.