Research On Preparation Process Of Calcium Carbonate Whisker And Ammonium Chloride By The Waste Residue Of 2-Cyanoguanidine

2-Cyanoguanidine slag quantity increases with the increasing of demand of 2-Cyanoguanidine. The waste residue takes up land and pollutes the environment seriously. The main component of 2-Cyanoguanidine slag is calcium carbonate, which could be produced calcium carbonate whisker, a kind of new type inorganic filler material. Simultaneously, the ammonium chloride can be producted from the mother liquid which prepared calcium carbonate whiskers, and the mother liquid can also continue to be used, thereby enabling water recycling.This research aims at improving and perfecting dicyandiamide waste production whisker process. The ternary system about NH4Cl-CaCO3-H2O was investigated, and obtained a series of physical parameters for the production of guidance.The dissolution kinetic of calcium carbonate in ammonium chloride solution was explored, and some kinetic parameters about calcium carbonate dissolved has been obtained, including apparent activation energy is 49.02 kJ·mol-1 and dissolution reaction order is 3.00, which provides calculation reference data for the production in late period.The preparation of calcium carbonate whiskers was optimized. Many factors, such as ammonium ion concentration, initial calcium ion concentration and solvent composition, were investigated by single factor experiments. The results showed that ammonium ions concentration in the mother liquor cannot exceed 0.9 mol·L-1, the initial calcium content is less than 0.02 mol-L’1 and solving the problem about whisker agglomeration initially. Ammonium chloride was obtained by cooling crystallization from the mother liquor that has been produced whisker. The partial conditions of cooling crystallization process were explored. The optimum conditions was determined that the cooling rate is 0.1 K·min-1, the stirring rate 250 rpm and the saturation temperature 50℃. The product was detected according to the national standard GB/T2946-2008, which meets the requirements of the qualified products in industry and first-grade products in agriculture.The results of this research improve the production technology about preparation of high added-value whisker used by 2-Cyanoguanidine slag, and achieve the comprehensive utilization of 2-Cyanoguanidine slag. The production technology is of good economic, environmental benefits and application prospects.