Patent ID: 7303794
Filing Date: 2007-12-04
Classification: B41M,C01F,C01P,C09C

Abstract:
1. A method for producing a precipitated calcium carbonate for ink jet recording paper comprising: a) admixing calcium oxide with water to produce a calcium hydroxide slurry; b) admixing a first amount of an organophosphonate followed by adding aluminum sulfate to the calcium hydroxide slurry; c) introducing carbon dioxide to the calcium hydroxide slurry to produce a precipitated calcium carbonate slurry; d) adding a second amount of organophosphonate to the precipitated calcium carbonate slurry; e) admixing phosphoric acid to the precipitated calcium carbonate slurry; f) screening and dewatering the calcium carbonate slurry; and g) milling the screened and dewatered precipitated calcium carbonate in the presence of an amphoteric or anionic dispersant after step (d), to produce a precipitated calcium carbonate product.