Production of calcium carbonate by the causticizing process in a kraft pulp mill

摘要

Precipitated calcium carbonate is produced as a by-product in the causticizing process of the kraft pulping process. Nippon Paper Industries, co.,ltd has used this Calcium Carbonate by the Causticizing process (CCC) as filler and coating pigment since nearly 30 years ago. By using this CCC as filler and coating pigment in a paper, lime kiln operation can be reduced or eliminated, resulting in the reduction of fuel consumption in the lime kiln operation.rnFurthermore, the build-up of non-process elements in the lime cycle, which is one of major concerns in the chemical recovery process, can be avoided because lime mud is taken out from the lime cycle with producing CCC.rnOn the other hands, our company has developed the morphology control technology of CCC. Initially, the precipitation of aragonite CCC was investigated at a laboratory scale. Then, the scale up trial was carried out at a pilot and a mill scale plant. Based on these fundamental research and developments, the industrial process to manufacture aragonite CCC with batch process has been established. Subsequently, the morphology control technology with continuous process was investigated at a laboratory scale and the results indicated that there was the possibility tornproduce aragonite CCC in the continuous operation.