Patent GB-647910-A (GB)
Title: Improvements in methods of producing purifying media for liquids
IPC: B01J20/04
Filed: 1947-09-23
Abstract: A purifying reagent is produced by mixing a magnesium-compound containing material with the so-called combined waste products resulting from the manufacture of Portland cement clinker and thereafter converting a portion of the mineral components of the mixture to activated oxide form.  Sufficient of the mineral components of the mixture may be converted to produce a final product having a pH from 11.3 to 12.4.  The conversion step may consist in calcining the mixture, preferably at a temperature of from 600 to 800 DEG  C. for from 5 to 30 minutes, the porosity of a portion of the inert components of the mixture being increased thereby at the same time.  The temperature and duration of the calcining may alternatively be chosen to bring about an ignition loss in the final product of from 2 to 10 per cent.  The "combined waste products" consist of calcite, mica, feldspar and quartz, with small proportions of talc, graphite, dolomite and iron pyrites.  They result from the grinding, classification, froth-flotation and thickening operations performed on the clayey and lime-bearing materials used in cement manufacture.  Several U.S.A.  Specifications relating to such manufacture are referred to in the Specification.  The magnesium compound may be magnesium hydroxide (brucite) comprising 30 to 70 per cent (preferably 50 per cent) of the mixture; or magnesium carbonate (magnesite) comprising 45 to 75 per cent (preferably 60 per cent). The "combined products" and the magnesium compound may be calcined separately and subsequently mixed.ALSO:A purifying reagent is produced by mixing a magnesium-compound-containing material with the so-called combined waste products resulting from the manufacture of Portland cement clinker and thereafter converting a portion of the mineral components of the mixture to activated oxide form. Sufficient of the mineral components of the mixture may be converted to produce a final product having a pH from 11.3 to 12.4.  The conversion step may consist in calcining the mixture, preferably at a temperature of from 600 to 800 DEG C for from 5 to 30 minutes, the porosity of a portion of the inert components of the mixture being increased thereby at the same time.  The temperature and duration of the calcining may alternatively be chosen to bring about an ignition loss in the final product of from 2 to 10 per cent.  The "combined waste products" consist of calcite, mica, feldspar and quartz, with small proportions of talc, graphite, dolomite and iron pyrites.  They result from the grinding, classification, froth flotation, and thickening operations performed on the clayey and lime-bearing materials used in cement manufacture. Several U.S.A. Specifications relating to such manufacture are referred to in the Specification. The magnesium compound may be magnesium hydroxide (brucite) comprising 30 to 70 per cent (preferably 50 per cent) of the mixture; or magnesium carbonate (magnesite) comprising 45 to 75 per cent (preferably 60 per cent). The "combined products" and the magnesium compound may be calcined separately and subsequently mixed.ALSO:A reagent is produced by mixing a magnesium-compound-containing material with the so-called combined waste products resulting from the manufacture of Portland cement clinker and thereafter converting a portion of the mineral components of the mixture to activated oxide form.  Sufficient of the mineral components of the mixture may be converted to produce a final product having a pH from 11.3 to 12.4. The conversion step may consist in calcining the mixture, preferably at a temperature from 600 DEG  to 800 DEG  C for from 5 to 30 minutes, the porosity of a portion of the inert components of the mixture being increased thereby at the same time.  The temperature and duration of the calcining may alternatively be chosen to bring about an ignition loss in the final product of from 2 to 10 per cent. The "combined waste products" consist of calcite, mica, feldspar and quartz, with small proportions of talc, graphite, dolomite and iron pyrites. They result from the grinding, classification, froth-flotation and thickening operations performed on the clayey and lime-bearing materials used in cement manufacture.  Several U.S.A. Specifications relating to such manufacture are referred to in the Specification.  The magnesium compound may be magnesium hydroxide (brucite) comprising 30 to 70 per cent (preferably 50 per cent) of the mixture; or magnesium carbonate (magnesite) comprising 45 to 75 per cent (preferably 60 per cent).  The "combined products" and the magnesium compound may be calcined separately and subsequently mixed.