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AssigneeMerichem Company
InventorHorace E. Willis, Jr.
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The present invention relates to the discovery of a method by which elemental sulfur may be delivered to a reaction zone, for gas-solids reaction, in the form of a concentrated, coherent, diffusion-resistant gas thereby permitting gas-solid reactions of greatly enhanced reaction rates. It has been found that sulfur, which is first vaporized at approximately 1 atmosphere pressure, and then super heated to at least 1270.degree. F. while in transit through a confined space, such as a transfer line, will debouch from said confined space into a reaction zone as a coherent gas which resist diffusion throughout the free space of the reaction zone. This coherent form of sulfur gas exhibits a dark reddish-violet color. The coherent form of sulfur gas, since it resists diffusion throughout the free space of the reaction zone, flows into concentrated contact with, and remains concentrated at, the solids surface, thereby producing a gas-solids reaction of greatly enhanced reaction rate. Utilizing the above discovery a process has been devised by which the sulfur values present in gypsum, particularly waste by-product gypsum produced by the wet process, may be recovered as SO.sub.2 with the concurrent production of lime.
A method for preparing elemental sulfur as a coherent diffusion resistant gas for reaction with solid reactants, comprising the steps of:
A method for obtaining sulfur dioxide by reacting calcium sulfate with a coherent diffusion resistant gaseous reagent form of elemental sulfur, comprising the steps of:
A method for obtaining sulfur dioxide and lime from calcium sulfate, comprising the steps of:
A method for recovering sulfur values from waste by-product gypsum produced by the wet process production of phosphoric acid as sulfur dioxide, comprising the steps of:
A method for recovering sulfur values from waste by-product gypsum produced by the wet process production of phosphoric acid and recycling such sulfur values as sulfuric acid for utilization as a reagent in the wet process, comprising the steps of:
Dependencies are inferred from the claim text.