Study On Utilization Of Wastes In Ammonia-Soda Factory

This dissertation summarizes the methods of preparation of superfine calciumcarbonate all over the world and gives a new technologic route, that is by------distiller waste and residual mother liquor in Solvay process are selected reasonably as basic materials, and calcium carbonate is prepared by the method of liquid reaction. The study has not only theoretical value but also apparent benefit for protecting environment and applicable extensively outlook.Our study includes:1 Cleaner Production Assessment (CPA) in ammonia-soda factory. In order to study the utilization of waste in soda factory, Cleaner Production Assessment (CPA) is carried out. This paper analyzes the reason, the process and the quantity of industry wastes created in ammonia-soda factory and investigates available components in the industry wastes. Finally, we studied the possibility of utilization of ammonia-soda industry wastes.2 Modification ammonia-soda process with clean technology. This paper innovates to a modified Solvay process. Contrast with Solvay process, the modified process only adds a condensation of clear distiller waste and a filtration process before distillation. Soda ash factories need not invest much money in rearrangement of the existing facilities. The advantage of the modification process is not only reducing waste dangerous for the natural environment: distiller waste and residual mother liquor, but also obtaining spherical superfine calcium carbonate precipitation. That is favorable for the improvement of soda factories economy as well as for environmental policy realization(NH₄)₂CO₃ + CaCl₂ → CaCO₃ ↓ + 2NH₄Cl3 Study on reaction process parameters of preparation superfine calcium carbonate. The influence of four independent parameters on the average particle size of calcium carbonate precipitation were taken into consideration in theexperiment:(1) the type and dosage of surfactants added to the reactorThe surfactant has obvious influence on the size of CaCO3 particles. The average size of the precipitated calcium carbonate depended on the type and dosage of surfactants added to the reactor. Effect of the op series surfactants are relative to molecular weight and coefficient n (the chain of polyoxyethylene). When n is equal to 15, CaCCb particles are highly dispersed, but the size increased when n exceeds 15.(2) mixing processes of distiller waste and residual mother liquor added to the reactor take placeThe average size of the precipitated calcium carbonate also depended on the mixing methods. Followed by titrating mixing, the particles were smaller than followed by rapid dropping mixing.(3) time of reactant settling in the reactorThe time of reactant settling in the reactor is 30—40min in which prepare spherical and highly dispersed particles are prepared.(4) temperature of the reaction processTemperature of the reaction process is 20—25 °C on which increase of particles size is slow and power is not wasted much.We make single factor analysis on those parameters to get optimum conditions of preparation superfine calcium carbonate. They are: utilization of cool residual mother liquor; the time of reactant settling in the reactor which is 30min, temperature of the reaction process which is 20°C, utilization of the surfactant Tween-80. Average particle size of calcium carbonate is smaller than 1 urn. Tests by scanning electron microscopy (SEM) prove that those particles are spherical, have better disperse property and great ratio surface area.