Study Of Comprehensive Utilization Technology Of Wastte Gypsum Using Catalysis

This set of process technology was designed to produce chemical products such as sulfuric acid, calcium chloride, ammonium hydroxide and dry ice, using phosphorus gypsum. This paper described the chemical composition and harm of phosphorus gypsum, described the current principal treatment of phosphorus gypsum, defined the purpose and content of the topics, and carried out a large number of theoretical researches about how to process phosphorus gypsum. Then this paper described the basic properties and industrial uses of experimental raw materials and products, completed the various conditions about dealing with phosphorus gypsum, and summed up the optimum conditions of producing chemical products using phosphorus gypsum. And then this paper introduced the products analysis method, and texted the products. Finally, this paper calculated the economic benefits of the technology, and described the potential environmental and social benefits.Through a series of exploratory testing, condition testing, the best conditions for comprehensive utilization of phosphorus gypsum had be found. Add water to the phosphorus gypsum according to a 3:1 ratio of water and material, stir for 5min, put it aside for 5min, separate the solid and the liquid, repeat it 3 times, and the water can be reused. Mix the phosphorus gypsum and ammonium bicarbonate, ammonium bicarbonate excess of 5%, add two volume of water, at room temperature, stir 50min, while collecting gas to produce dry ice. Separate the above-mentioned material, solid and concentrated hydrochloric acid mixed react until there is no gas released at room temperature, at the same time, collect gas to produce dry ice. After ammonium sulfate solution was evaporated, mix it with catalyst, catalyst excess of 50%, at temperature of 500℃, react 1.5h, and while absorb ammonia gas to produce ammonium hydroxide. Then continue to heat up to 800℃, react 0.5h, and while absorb trioxide with concentrated sulfuric acid to produce the required concentration sulfuric acid. The remaining solids can be got back to the first step reaction, or return to produce phosphoric acid.