Gnb Batteries Inc.

Fsi Corporation

Jitesh R Mehta

Andrew H Larson

Don C Burkman

Francis M Dunlevey

Cooky Mezaki

A process for drying semiconductor wafers or similar substrates maintains the substrates in a static position to avoid the generation of undesired particulate. The substrates are maintained within the apparatus at an angle of approximately 30.degree. from the vertical to facilitate complete drainage of the processing fluid. According to this invention, the substrates are positioned in the chamber of the apparatus at the appropriate angle, the chamber is closed in a fluid tight seal and filled with the processing fluid, until the fluid overflows through a vacuum valve. While maintaining the chamber completely filled, vacuum aspiration is continued to degas the chamber. While continuing vacuum aspiration of the chamber, a vacuum assisted drain valve is opened, and clean dry inert gas is introduced above the draining fluid. The draining step assures that any droplets remain with the draining fluid so that the substrates emerge dry as the fluid drains away. The inert gas flow is discontinued and vacuum aspiration is maintained briefly after the chamber has drained. The vacuum aspiration is discontinued and the chamber is repressurized to essentially ambient pressure prior to opening the chamber to remove the dry substrates.

Apparatus and process for static drying of substrates

A process for metal-enrichment of lead bullion, wherein an alkali metal-desired metal intermetallic, such as sodium-antimony intermetallic, is added as a refining dross to the bullion and the desired metal is stripped from the dross and recovered as an enriched bullion. The process includes the steps of heating the lead bullion, in which the desired metal is to be recovered, to a temperature between 650.degree. F. and 900.degree. F.; agitating the molten bullion; adding said alkali metal-desired metal intermetallic to said bullion; mixing said intermetallic into said bullion; adding a stripping reagent for stripping said desired metal from said intermetallic; forming a desired metal-enriched lead bullion and a residue dross substantially void of said desired metal; and separating said enriched bullion from said residue dross. The process may also require a cleansing step to cleanse said enriched lead bullion of any said alkali metal in solution. Through the control of temperature, additions of stripping and cleansing reagents and agitation, the process provides economies of materials, energy, time and labor over conventional metal recovery processes.

Process for metal-enrichment of lead bullion

An improved process for refining lead bullion containing antimony, in which the bullion is initially heated in a refining vessel to about 25.degree. F. (14.degree. C.) above the bullion melting point, and is thereafter kept molten primarily by exothermic process reactions. The process includes the steps of melting the lead-antimony bullion, agitating the bullion, adding caustic soda and metallic sodium to form an antimony-rich skimmable refining dross comprising a sodium-antimony intermetallic and separating the dross from the refined bullion. Along with antimony, other elements, such as arsenic, cadmium, copper, nickel, silver, sulfur, selenium, tellurium and zinc, if present in the bullion, are also removed in the dross by the sodium. The antimony-rich dross is accumulated for subsequent use. The process further comprises a cleansing operation wherein sodium present in solution in the refined bullion is removed using cleansing agents. This refining process is performed at a temperature between 600.degree. F. (316.degree. C.) and 800.degree. F. (427.degree. C.). Through the control of temperature, reagent addition and agitation, the process provides an environmentally nonpolluting and controlled process in which economies of materials, energy, time and labor are realized over conventional refining processes.

Refining process for removing antimony from lead bullion

A batch process for desilverizing and refining lead bullion containing antimony and a low silver content, including the steps of melting the lead bullion, adding calcium to form a floating silver-rich dross containing a silver-antimony-calcium compound and separating the dross from the desilverized, molten lead bullion. The process further comprises a plurality of successive batch operations wherein silver-rich dross is separated and accumulated in each batch operation for subsequent processing. The successive batch operations are maintained at about 400.degree. C. in order to effect significant savings in energy, time and labor over processes previously used.

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Eagan, MN, United States of America

Jitesh R Mehta