Taiheiyo Cement Corp. filed a patent on 11 May 2011 for a new calcium removal method designed to reduce operating costs in cement production by avoiding the addition of potassium carbonate to remove the calcium as per conventional methods.
According to the abstract posted by the World Intellectual Property Ogranization: : "Provided is a calcium removal method that can reduce operating costs. A solution (L2) that contains potassium and/or sodium and calcium is passed through an ion exchange resin (35) and the potassium and/or sodium and calcium is isolated. The addition of potassium carbonate to remove calcium, as in conventional methods, is not necessary, so operating costs can be greatly reduced. The exchange timing of calcium containing water (L3) discharged from the ion exchange resin and saline (L4) can be controlled on the basis of the measured calcium or chlorine concentrations in the liquid discharged from the ion exchange resin and one or more of the measurement results selected from a group consisting of pH and electrical conductivity. A solution (L1) obtained by washing chlorine bypass dust (D) generated in a cement baking process or a percolate (W) from the final disposal site can be used as the solution."