| Picking of Hydrochloric acid has been used to remove the oxide skin and iron scale before overlaying at room temperature.A great deal of acid mist can be volatilized by the high concentrate Hydrochloric acid with 20～25 percent, the more acid mist has been volatilized; the worse workshop environment has been made.It hazarded manufacturing facility and people's health. At the same time, the atmosphere has been polluted. The picking waste waters became a serious problem that should be disposed. It sometimes has been discharged into the river especially the medium and small-sized enterprises. So the water resource has been polluted. With the starting of the recycling economy activities which asked for the manufactory and enterprises act with the code of "Reduction,reusing, recycling", the descaling circulatory system of FeCl3-HCl has been studied and designed in this paper.The best batch formula of descaling circulatory system has been developed by the orthogonal test with the FeCl3 33.82%, HCl 8%,urotropine 0.6%,NaCl 2%,sodium dodecyl sulfate 0.12% percent in the batch formula. Compared with the traditional picking process, less descaling time would be used by the best batch formula, smoother and brilliant whiter surface the matrix has.At the same time, this descaling method has little influence on the mechanical property of matrix, which can make sure the carrying on of overlaying favourably and reduce the parent materials.Compared with the oxidation efficiency, the apparent quality and surface roughness of matrix after the descaling of post-oxidation of the picking waste waters, the cost of oxidation, etc. we have draw a conclusion that the best oxidation method was H2O2+air. By this means, the discard solution has been reused with the same descaling effect.The optimum preparation conditions of ferric chloride polymerization has been developed by the orthogonal test with the OH-/Fe3+=2,P/Fe3+=0.12,the best coagulation temperature is 40℃and the aging time is 1.5h.It has been proved that the coagulation effect was better than the market ferric chloride, and we can see that with this technological condition, the post-oxidation of discard solution has the same of coagulation effect.The rust-removing circulatory system of FeCl3-HCl and correspond attachment has been designed in this paper. Descaling slot:specifications for the 3×2×1m,with the fiber glass reinforced plastics(FRP) as the steel shafts of the lining and the make concrete shell. There was a hole for the entrance of air at left side; Air-oxide reactor:specifications for Φ2×2.5,the same material has been used for the kettle selection.This reactor was a sealing system that has three orifices for the air, H2O2 and HCl at the top; Reaction trough: specifications forΦ2×2.5m,the same material as the former,.With two appurtenances:a slot insulation layer and a mixing devices.With the design of the circulatory system,on the one hand, it can overcome the damage caused by the acid mist volatilizing of high concentration of hydrochloric acid,on the other hand,the propriety reusing of the discard solution can reduce the cost of the descaling and control the discharging of the discard solution that avoid the water's pollution effectively. It should be a reasonable feasible circulatory system of energy-saving abatement,resources saving descaling and friendly environment.
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