Method for the conversion of gypsum to elemental sulfur
AssigneeGas Research Institute
InventorMark A. Paisley
Life of this patent
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Abstract
A process for the recovery of sulfur and carbon monoxide from metal sulfates in which the carbon monoxide is recycled as a reducing agent for reaction with the metal sulfate. Metal sulfates such as gypsum (calcium sulfate dihydrate) are processed to form sulfur dioxide. The sulfur dioxide is contacted with carbonaceous matter at sufficiently high temperature to form elemental sulfur and carbon monoxide. The carbon monoxide is then recycled for use as a reducing agent in the initial processing of the metal sulfate.
Claims30
A process for sulfur recovery from a metal sulfate, which comprises the steps of:
- feeding said metal sulfate to a first reactor;
- feeding a reducing agent to said first reactor, said reducing agent including recycle carbon monoxide from a step of contacting sulfur dioxide with a carbonaceous matter;
- contacting said metal sulfate and said reducing agent at a temperature and for a period of time sufficient to effect reduction of said metal sulfate to a metal sulfide thereby producing a product stream containing said metal sulfide and gaseous waste by-products of said reduction;
- removing said product stream from said first reactor;
- separating said metal sulfide from said gaseous waste by-products in said product stream;
- oxidizing said metal sulfide to form a metal oxide and sulfur dioxide in a second reactor;
- contacting said sulfur dioxide with carbonaceous matter to produce elemental sulfur and said recycle carbon monoxide, said recycle carbon monoxide being produced in sufficient quantity and purity for use in said step of reducing said metal sulfate to form said metal sulfate;
- recycling said recycle carbon monoxide for use as a portion of said reducing agent in said step of reducing said metal sulfate to form said metal sulfide;
- and
- incinerating said waste by-products from said reduction and using the heat produced thereby to heat said metal sulfate fed to said first reactor.
An apparatus for the conversion of metal sulfates to sulfur and carbon monoxide with recycle of said carbon monoxide comprising:
- a first reactor for reducing a metal sulfate to a corresponding sulfide;
- means for feeding said metal sulfate and a reducing agent to said first reactor;
- means for contacting said metal sulfate and said reducing agent at a temperature and for a period of time sufficient to effect reduction of said metal sulfate to the corresponding sulfide thereby producing a product stream containing said sulfide and waste by-products;
- means for removing said product stream from said first reactor;
- means for separating said sulfide from said waste by-products;
- a second reactor for oxidizing said sulfide to a corresponding oxide;
- means for feeding said sulfide and an oxidizing agent to said second reactor;
- means for contacting said sulfide and said oxidizing agent at a temperature and for a period of time sufficient to effect oxidation of said sulfide to said corresponding oxide and sulfur dioxide thereby producing a product stream containing said oxide and sulfur dioxide;
- means for removing said oxide and said sulfur dioxide from said second reactor;
- means for separating said oxide from said sulfur dioxide;
- a third reactor for reducing said sulfur dioxide to sulfur and carbon monoxide;
- means for feeding said sulfur dioxide and a carbonaceous material to said third reactor;
- means for contacting said sulfur dioxide and said reducing agent at a temperature and for a period of time sufficient to effect the production of a gaseous mixture of carbon monoxide and sulfur;
- means for removing said gaseous mixture from said third reactor;
- means for separating said sulfur from said carbon monoxide;
- means for feeding said carbon monoxide to said first reactor;
- and
- means for incinerating said waste by-products of said reduction and heat exchanging said waste by-products with said metal sulfate entering said first reactor through said feeding means.
Dependencies are inferred from the claim text.