Study On Comprehensive Utilization Of Alkali Slag In Ammonia Plant

Alkali slag is the muddy waste which is produced in the process of soda production by ammonia methods in soda plant,commonly known as alkali residue.In the process of soda production by ammonia methods,a large number of waste will be poured due to defect process,resulting in a huge number of alkali slag over the years.Now the approach of alkali slag is mostly stockpiled,forming dams with few mature alkali slag treatment.But it is not only covering large land and suffering dam break but also producing dust because of its dry surface,which cause atmospheric environment pollution.Therefore,the utilization of alkali slag has become the focus of domestic and international environmental protection industry research.In view of this situation,this paper has done the following four aspects of research work:1.Study on that alkali slag absorbs methylene blue in static state.The main research on the adsorption of methylene blue dye wastewater by alkali slag slurry is to waste with waste.In this experiment,the adsorption equilibrium time of methylene blue dye wastewater by alkali slag slurry is 180 min,the optimum adsorption alkali slag concentration is 10 g·L-1,the optimum adsorption pH is 8.5,and the adsorption efficiency decreases with the initial concentration of methylene blue but adsorption capacity increases.Meanwhile the maximum adsorption efficiency is up to 98.9%and the adsorption experiment is endothermic.2.Study the application of alkali slag in wet flue gas desulfurization.In this experiment,the alkali slag slurry is used as desulfurizer.With the experimental conditions changed by controlling the variable method,the optimal desulfurization scheme was obtained by comparing the experimental results.The optimum desulfurization conditions are as follows:the concentration of sulfur dioxide is 10 mL·min-1,the flow rate of nitrogen is 1.04 L·min-1,the concentration of alkali slag is 40 g·L-1,the particle size of alkali slag is less than or equal to 60 mesh.3.Study on the rule in the process of evaporation and concentration of the alkali slag liquid.In this experiment,the change of boiling point,the change of liquid and solid composition,and the precipitation of calcium chloride and sodium chloride are studied.The results show that the optimum temperature of separating sodium chloride and sodium chloride is 120 ℃.The optimum temperature of the separating calcium chloride and sodium chloride from water wash of alkali slag is 124 ℃.The liquid of alkali slag and hydrochloric acid reaction can produce directly calcium chloride products,due to less sodium chloride content.4.Study on the utilization of calcium chloride in the reaction of alkali slag and hydrochloric acid.The factors influencing the yield of calcium chloride in this experiment are the addition of hydrochloric acid,the concentration of hydrochloric acid,the particle size of alkali slag,the pH value,the reaction time and the reaction temperature.By analyzing the results of the five-factor orthogonal experiment,the optimal combination of the calcium chloride yield is that the addition of hydrochloric acid is 3 moL·L-1,the particle size is 60 mesh,the concentration of hydrochloric acid is 1:6,the pH value is 10,The reaction time is 150 min,the reaction temperature is 100 ℃.And the purity of calcium chloride is tested.The results show that the content of calcium is up to 96%.