Patent ID: 7048900

Claim:
A method for the hydrothermal production of calcium silicate hydrate and calcium carbonate in a set of common reactors, said method comprising: (a) providing an aqueous lime slurry, said aqueous lime slurry comprising (i) Ca(OH) 2 solids and (ii) dissolved Ca(OH) 2 in the form of Ca ++ ions; (b) screening grit from said aqueous lime slurry; (c) conditioning said aqueous lime slurry to a predetermined temperature; (d) feeding a first portion of said aqueous lime slurry into a first reactor of said set of common reactors; (e) agitating the contents of said first reactor at super-atmospheric pressure; (f) introducing a stream of CO 2 into said aqueous lime slurry in said first reactor, to form CO 3 −2 ; (g) reacting said CO 3 −2 ; and said Ca ++ in a carbonation reaction to produce insoluble precipitated calcium carbonate (CaCO 3 ) in said first reactor; (h) removing said insoluble precipitated calcium carbonate and associated water from said first reactor; (i) charging a second reactor of said set of common reactors with a first aqueous silica slurry comprising silica at a concentration of from about 1 to about 1.5 pounds of silica per gallon of said first aqueous silica slurry; (j) charging said second reactor of said set of common reactors with a second portion of said aqueous lime slurry; (k) heating the contents of said second reactor under hydrothermal conditions to produce a calcium silicate; (l) removing said calcium silicate from said second reactor; (m) switching feed of said first portion of said aqueous lime slurry and said CO 2 to said second reactor from said frist reactor, and switching feed of said first aqueous silica slurry and said second portion of aqueous lime slurry to said first reactor, so that precipitated calcium carbonate is produced in said second reactor, and calcium silicate is produced in said first reactor.