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US 5,352,647 AGranted
Composition for separating out noxious substances from gases and exhaust gases
AssigneeFTU GmbH
InventorHermann Suchenwirth
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AssigneeFTU GmbH
InventorHermann Suchenwirth
Estimating the term…
A composition for separating out volatile pollutants from gases and exhaust gases consists of calcium hydroxide and water-soluble salts of sulfur-containing compounds, e.g., mercaptans, sulfides, polysulfides, polythionates and thiosulfates, or elementary sulfur which are used in combination with surface-active substances. Possible ways to produce the composition include adding the sulfur-containing compounds to the quicklime during slaking, to the slaking water, or, subsequent to slaking, to calcium hydroxide. The compositions are used for removing the volatile heavy metals, particularly mercury, arsenic, cadmium, thallium, antimony and lead, at temperatures ranging from 20.degree. to 400.degree. C. For this purpose, the composition is blown as powder into the exhaust gas stream, and the resultant products are separated out at fabric filters. Upon addition of surface-active substances, volatile organic pollutants are removed simultaneously with the aforementioned inorganic pollutants.
A composition for removing heavy metals from exhaust gases comprising a powder of calcium hydroxide and 0.01 to 5 wt. %, based on the calcium hydroxide, of at least one water-soluble salt of a sulfur containing substance which sulfur-containing substances are selected from the group consisting of polysulfides, polythionates and thiosulfates.
A composition for removing heavy metals and/or organic pollutants from exhaust gases comprising a powder of calcium hydroxide, 0.5 to 10% by weight, based on the calcium hydroxide, of at least one surface-active substance and 0.5 to 5% by weight, based on calcium hydroxide, of powdered sulfur, with the at least one surface active substance being selected from the group consisting of active carbon, open hearth, lignite coke, activated aluminum oxide, silica gel and crystalline silica.
A process for making dry or hydrous powders of a calcium hydroxide composition which is useful for removing heavy metals and/or organic pollutants from exhaust gases, comprises slaking quicklime in the presence of a sulfur compound, which sulfur compound is a water-soluble salt of a sulfur containing substance, a combination of a water-soluble salt of a sulfur containing substance and a surface active substance, sulfur, or sulfur applied on a surface active substance, wherein the sulfur containing substance is selected from the group consisting of polysulfides, polythionates and thiosulfates and the surface active substance is selected from the group consisting of active carbon, open hearth lignite coke, activated aluminum oxide, silica gel and crystalline silica.
A process for making dry or hydrous powders of a calcium hydroxide composition which is useful for removing heavy metals and/or organic pollutants from exhaust gases comprises slaking quicklime so as to form calcium hydroxide and then introducing a sulfur compound onto the calcium hydroxide, which sulfur compound is a water soluble salt of a sulfur containing substance, a combination of a water soluble salt of a sulfur containing substance and at least one surface active substance, sulfur, or sulfur applied on a surface active substance, wherein the sulfur containing substance is selected from the group consisting of polysulfides, polythionates, and thiosulfates, and the surface active substance is selected from the group consisting of active carbon, open hearth lignite coal, activated aluminum oxide, silica gel and crystalline silica.
Dependencies are inferred from the claim text.