| The receipting water substance shall be polluted seriously due to directing emission during the rear earth baking, which the great many sulfuric acid shall be consumed and the fluorine contained in the rear earth fines, the wasted acid contained sulfuric acid and fluorine acid out of the smoke clearing system would be occurred. Up to now, some enterprises shall treat them with lime neutralization in high cost, but many problems shall be occurred due to these unreasonable processes used such as sorority and much salt occurred out of them. This environment pollution issue has restricted the rear earth enterprises developing in the future. For the waste water from large scale rear earth enterprise, the well-know engineering experience example has not established by now. The real way of solving such environment pollution and recycling of resources shall be realized through finding a practical engineering solution.This paper analysis the existing conditions of waste water contained acid treatment and re-using technology based on the waste water out of rear earth enterprises located in Baotou area, such as the treatment waste sulfuric acid and waste water contained acid, the treatment of acid waste water contained fluorine and the disadvantage of using lime neutralization, it is suggested that the regeneration and cycling of wasted acid and water contained acid via evaporation separating mixed acid, recycling using the dense sulfuric acid and rear earth fines baking, using the received fluorine acid for compounding and producing the electrolysed Aluminum. This is an optimized solution for wasted substances regeneration and with the features of circulation of economic.This paper is consists of how to treat and how to use the process and technicalplant for the whole engineering. Based on the tested result, it is found that the technical process parameters and determined the data, calculation and design the process according to the related rules and codes, giving the list of equipment for such recommended solution, balance of materials and section and plan of general arrangement of such process solution as well as giving the estimated investment and cost analysis.The recommended solution which referred to the treatment capacity is 40000t wasted acid, the received sulfuric acid is 11 OOOt in weight and the fluoridated salt is 4000t in weight accounted with cryolite as well as the quality of fluoridated salt is able to reach the industry grade. The total investment shall be 8479.60* 104 in RMB, in which the investment for sulfuric acid evaporation and concentrated system shall be 6387.36x104in RMB and the investment for fluoridated salt recycling shall be 2029.24x104 in RMB, the annual operation costs shall be 1606.89xl04 in RMB and the estimated ration of investment shall be 14% and the recovery period shall be seven years. The recovery ration of sulfuric acid shall be 85% and the reaction ration of hydrofluoric acid shall be 95%. It is features with illustrious economic and environment efficiency, so it can be recommended widely in the future and with a bright foreground. |
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