Experimental Study And Process Design For Disposal Of High Concentration Ammonia Nitrogen Waste Water To Recovery Ammonia Nitrogen In Rare Earth Smelting

Essaying managing the waste water in the rare earth(RE) smelted that contains ammoniate nitrogen for reuses of resource, through the experiment based on the basic theory and method, the method of disposal and process parameters are confirmed and the process design about ammoniate nitrogen waste water of Inner Mongolia Rare Earth High-Technology Ltd is finished.(1) The natural zeolite adsorption process is effective on filtering ammoniate nitrogen of the waste water in the RE smelted, and the removing efficiency has exceeded 50%. While the original concentration of the waste water is so high that the waste water managed is difficult to get the effluent stander, and the zeolite's consumption is excessive. So this method is not adapted to the actual projects.(2) In some experimental investigations of managing the ammoniate nitrogen of the waste water in the RE smelted with ammonium magnesium phosphate settling method, through three chemical preciption process, on the condition that pH = 9.0, T = 68F, the concentration of ammoniate nitrogen of the wasted water could drop from 13031mg/L to 200mg/L in 20 minutes according the reagent combination that Mg : N : P = 1.3 : 1.0 : 1.1.But except for the high-cost, the waste water also can't get the effluent stander, so this method is not adapted to the actual projects too.(3) With the basic evaporating ammonia method uniting the technique of the recovering ammonia, the ammonia and nitrogen conception of the sulfide waste water managed is less than 25mg/L, which is proved by the semi-industrial, and it can get the effluent stander. So this method is adapted to the actual projects.(4) With the direct expansion crystallization uniting the technique of the recovering ammonia chloride, the ammoniate nitrogen conception of the chloramines waste water managed is less than 25mg/L, which is proved by the semi-industrial, and it can get theeffluent stander. Except that, the ammonium chloride can get the industrial grade stander so it can be soled. So this method is also adapted to the actual projects.(5) The process designs of disposal of ammonia nitrogen from Rare Earth High-Technology Ltd are finished about ammonia sulfate water with the alkaline evaporation ammonia method and chloramines water with direct evaporation method. Ammonia sulfate water 21.6xl04m3/a is treated and industrial ammonia water 4300t/a(16~18%) is recovered, at the same time ammonia chloride water 18.7xl04m3/a is treated and industrial ammonia chloride is recovered in this process designs. The treated water is up to standard of waste water or reuse water. The project total investment is 1525xlO4Yuan, product sales is 1216.80xl04m4 Yuan, inter rate of return is 7.26%, and it's rate of return on investment is 7.75%, which have better environmental benefit and economic benefit.