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无污染磷化膜是在下述磷酸锌溶液中制备的(含量 g/L):Zn0.4～30,P_2O_5 4～30,NO_3 5～50,Fe(Ⅱ)≤10,Fe(Ⅲ)≤0.3,游离P_2O_5:总P_2O_5=(0.6～0.4):1,Zn:NO_3:P_2O_5=(0.8～0.3):(0.17～0.40):1.溶液中Fe(Ⅱ)含量仅用硝酸盐氧化法来调整,结果生成亚硝酸盐.最好是用硝酸盐和含氧气体、H_2O_2和/或亚硝酸气体一起来调整 Fe(Ⅱ)含量,磷化后用二个以上的逆流清洗槽清洗,最后一个槽采用去离子水.每一清洗槽的水均可用于前一清洗槽或磷酸盐溶液,这样,从磷酸盐槽中带出的含有少量或不含盐的水可以从逆流清洗系统的磷酸盐富集水中得到补充.
Pollution-free phosphating film is prepared in the following zinc phosphate solution (content g / L): Zn0.4-30, P204-530, NO3-5-50, Fe (II) <= 10, Fe (III) , Free P_2O_5: total P_2O_5 = (0.6 ~ 0.4): 1, Zn: NO_3: P_2O_5 = (0.8 ~ 0.3) :( 0.17 ~ 0.40): 1. The content of Fe (Ⅱ) in the solution is only adjusted by nitrate oxidation , Resulting in the formation of nitrite.It is best to use nitrate and oxygen-containing gas, H_2O_2 and / or nitrous acid together to adjust the Fe (Ⅱ) content, after phosphating with more than two countercurrent cleaning tank cleaning, the last tank Deionized water is used.The water in each tank can be used in the previous tank or in the phosphate solution so that the water with little or no salt brought out of the tank can be swept from the phosphate-rich Catchment gets replenished.