Analysis And Reuse Of Waste Zincate Solutions

Zincate treatment is an important technique before the process of aluminum and alloy plating. The oxide film on the aluminum and its alloy workpiece can be removed and the combination ability between workpiece and plating can be improved through zincate treatment. Effective analysis of elements of waste zincate solutions can accurately determine the zincate treatment process and understand the reaction process better. As waste zincate solutions had the characteristics of high concentration,component complex and containning heavy metals and toxic cyanide, so there were no well-used ways of dealing with it. Therefore, it's pressure to establish a appropriate way of dealing with waste zincate solutions.The paper established a series of Ultraviolet Absorption Spectrometry ways to analysis the metal ions in waste zincate solutions through experiments.1. sodium salicylate Spectrometry analysis ways of Fe³⁺: use sodium salicylate as color agent, between pH value of 4-6, Fe³⁺ can react with sodium salicylate and form steady brown Complexing substance. The best absorb wavelength was 475nm.While the concentration of Cu²⁺ less than 2.56g/L and Ni²⁺ less than 22.3g/L, it will not affect the determination of Fe³⁺, and Zn²⁺ has no effect to the determination. The method needn't add other reagents and it's rapid and accurate, so it can be used as the on-site way of determination of Fe³⁺ in zincate solutions.2. Bis(cyclohexanone)oxalyldihydrazone (BCO) Spectrometry analysis ways of Cu2+: The reaction of Cu2+ and Bis(cyclohexanone)oxalyldihydrazone (BCO) was studied, and the method of determine the concentration of Cu2+ was established with Ultraviolet Absorption Spectrometry. This method use ammonium citrate as masking reagent and ammonium chloride-ammonia as the alkaline buffer to adjust the pH between 9-10. The reactant of Cu2+ and BCO was steady in the aqueous pHase and the absorption peak value is 600nm. The analysis range of Cu2+ was 0.20-4.00mg/L. The effects of masking reagent,buffer and color agent dosage and main metal ion(Fe,Zn,Ni,Al) on determination of Cu2+were studied.3. Ferron Spectrometry analysis ways of Al³⁺: The experiment refer to the determine way of Al³⁺ in boiler water and cooling water (GB 12154-88).The soluble aluminum in solutions react with Ferron(7-iodine-8-hydroxyquinoline-5-sulfonic acid)and form steady yellow Complexing substance. The absorption peak value of the product is 365nm and the best pH value is about 5.0. The analysis range of the way is 0.2-2 mg/L.The paper takes recycle and reuse of resources into account, found the removal of aluminum and reusing way to deal with waste zincate solutions. In order to avoid impurity, the way just adjust the pH value of the solution to change the modality of aluminum and separate it from the solution. The experiment indicated that at about the pH value 5, the removel efficiency of aluminum is best, about 38.59%- 64.68% , this make the components of waste zincate solutions conform to the zincate solutions and reach the purpose of reusing aluminum.The analyzing method established in the previous research can be applied to effectively determine the concentration metal ions in waste zincate solutions by using simple equipments and reagents, it is convenient in practice activities and can be spreaded among factories.The removel of aluminum and recycle method has been accords with the savingresources and decreasing waste policy of water disposal technic at present, and it canrecycle valuable metal resources, so it's a clean way.