Research And Development Of Preparation Technology For Phosphoric Acid By Blast Furnace Process

The phosphoric acid is a basic stock of phosphorus chemical product in the preparation of fine phosphate and phosphoric acid compound fertilizer, and so on has a wide rage of applications in the industry, agriculture and the national defense war industry as well as the cutting-edge electron. Currently, industrial phosphoric acid production, there are three main methods:aqueous method phosphoric acid, electrothermics phosphoric acid, kiln law phosphoric acid. A variety of phosphoric acid preparation methods have their raw materials adaptable, level of energy consumption, environmental impact and product purity.The research seeks to explore a wide adaptability of raw materials,low level of energy consumption, less environmental impact and high purity phosphoric acid new technology-phosphoric acid by blast furnace process, use the coke (or anthracite) as fuel, phosphate rock as raw material and flux, high temperature melting in a blast furnace, elemental phosphorus restore in a steam form form phosphate rock, meanwhile melt preparation of phosphorus in the water quench condensing the amount of nutrients (silicon, calcium, magnesium) fertilizer, separation of rare or precious metals (nickel, titanium) and so on, Therefore, this research for achieving P resources, especially low-grade phosphorus resources comprehensive reasonable utilization,there are have a certain significance for raising the phosphoric acid industrial technology level. Main contents and conclusions are as follows:(1)Analysis the single factor phosphate reduction (reduction time, reduction temperature, silicon alcium ratio) on the reduction rate of phosphate rock., Determine the preferential reduction of phosphate rock conditions. The results showed that reaction temperature is an important factor to the phosphate reduction rate in the phosphate rock reduction process. The higher the temperature the faster reduction, achieve the same reduction rate, the shorter the time required. Than silicon alcium ratio is also an important factor, with the increase of silicon alcium ratio, also increased the reduction rate. Consider the reduction rate and preparate certain silicon alcium ratio,so the amount of silica to be added. We believe that the silicon alcium ratio selected preferably between 0.8 and 1.0. Phosphate rock rate change very small when the reaction time at 1200℃, however, when increasing the temperature to 1300℃-1500℃,phosphate reduction rate with the reaction time is relatively large, and has a certain regularity.(2)Analyze the chemical composition of slag in the melting point of the slag, comprehensive analysis and select the NaCl and KC1 as a flux. Through research of adding NaCl and KC1 after the reduction rate of Phosphate rock, they are both conducive to the promotion of phosphate rock reduction rate, KC1 as a flux is more obvious than NaCl as a flux, enhance the range of about 1% to 10%; High dosage (10%) or low dosage (5%) did not significantly increase phosphate rock reduction rate, add the amount of 5% to 7% for the best.(3)Discuss reduction of phosphate rock reactivity and reduction mechanism, considering:silica with the phosphate rock defluorination firstly react to generate 2CaF2·SiO2 and Ca3 (PO4) 2, the production Ca3 (PO4) 2 is sends the coke surface by diffusion response through the fusing liquid phase proliferation to return to original state. Assume that reduction reaction at high temperatures controlled by diffusion, carry on dynamics experiment based on this assumption to the reduction process, determine the dynamic model, and fits speed constant K, provide the essential basic theory data for the industrialization production.