| Hydrometallurgy refinery process usually produces large quantities of wastewater, which was harmful to the environment. The metals contained in the waste water were hard to get disposal efficiently, which contained appreciable amount of heavy metals such as Cu (Ⅱ), Ni(Ⅱ), Co (Ⅱ), Zn (Ⅱ), Cd (Ⅱ), it was an important task to separate and recover these metals. For waste water with low pH value, low metal concentration, composition complex and also different for the metal recovery, it is a most urgent task to find a efficient way to treat with the waste water. Currently, the solvent extraction technology which comes with the development of the hydrometallurgy was a important method in the waste water treatment. Also, it is difficult for the single extractant alone to recover metals in the treatment with ploy-metallic complex sulphuric acid solution. So it was necessary to develop economically excellence performance synergistic solvent extraction system. In this paper, the separation effect and rules of various types in the separation of different heavy metal ions by the organic acid, such as carboxylic acids and nitrogen-containing oxime extractant was first reviewed. The research results in the literature showed that a reasonable combination of the extractant will produce a synergistic effect with the metal ions, this synergistic effect significantly improves the extraction selectivity and separation of various metal ions, it is reasonable to believe that the synergistic extraction technology in the heavy metal recycling in wastewater will have broad prospects.The on-site survey was done, and the sample in the typical smelt company of our country was collected and analyzed. Further, the quality and quantity of the water solution was acquired, and it was determined that the type and concentration range of the metal of the objects to be processed. Then, the extraction system was focused to choose the right synergistic solvent extraction system, the metal extraction percentage vs. equilibrium pH of each metals was explored, it was found that the synergies occurred that mix extraction system of Versatic10/Mextral984H effected on the extraction of metal ions. The process conditions of selected synergistic system Versatic10/Mextra1984H for the separation and recovery of copper, nickel, cobalt, zinc, cadmium was optimized, and the extraction kinetics and mechanism of co-extraction system was studied, the synergistic extraction for the separation of wastewater to recovery heavy metal ions in industrial practice could provide theoretical guidance in industry.In this paper, the use of P204was studied and the extraction and separation of copper, nickel, cobalt, zinc, cadmium from other heavy metal ions such as magnesium ions calcium metal separation process difficult to achieve. Using Versatic10extraction and separation of copper, nickel, cobalt, zinc, cadmium heavy metal ions and magnesium, calcium metal ion separation process is more difficult to achieve, it was found through experiments VersaticlO and Mexta1984H with energy for copper, nickel, cobalt, zinc, cadmium extraction of metal ions to produce a synergistic effect, separation and recovery of heavy metal ions is feasible through synergistic extraction system Versatic10/Mextra1984H, the optimum conditions for the synergistic extraction system experiment was also determined.The ratio of the mixing extraction system, the extraction temperature, pH, equilibrium time and phase ratio had been optimized in the conditional experiment, the selected condition of the Versatic10/Mextra1984H synergistic solvent extraction system was determined. Which the temperature was40℃, solvent extraction composition0.5M Versatic10/0.5M Mextra1984H diluted in MextralDT100, phase ratio1:1, extraction time20min, phase separation time10min. Under this condition,△pH50(Ni-Ca)=3.8,△pH50(Ni-Mg)=4-8,△pH50(Co-Ca)=3.0,△pH50(Co-Mg)=4,△pH50(Zn-Ca)=2.0,△pHso(Zn-Mg)"2.9, which Cu, Ni, Co, Zn and Cd have a good separation effect to the other metal ions such as magnesium, calcium impurity. On the some time, with the acidic pH value, the synergistic extraction system present strong extractability of metals, and also produce intervals between different metal values, which come as three groups Cu、Ni/Co、Zn/Cd. Under the same conditions, taking into account of various factors, the optimal pH conditions of copper, nickel, cobalt, zinc, cadmium and separation is5.66. When considering the stripping process, and the acidic concentration5g/L H2SO4Zn, Cd can be stripped and small amount of Co is also co-stripped. And when the acid concentration of15g/L, Ni, Co can be stripped, at higher concentrations of100g/L, Cu was extracted out time, In terms of time of extraction, Cu, Ni, Co metal can be reached within a time5min extraction rate of more than80%, Zn, Cd metal extraction is slow, which was about10min to achieve the extraction ratio of60%, and20min to reach80%after the extraction rate. When taking into account of the stripping process, the stripping time of Co, Zn, Cd reached90%, which showed in a very short stripping rate while the Ni stripping rate is about5min to reach90%. The Mechanism of Versatic10/Mextra1984H synergistic extraction of copper, nickel, cobalt, zinc, cadmium was studied, and it was found that in the extraction of nickel, cobalt ions, the synergistic extraction system Versatic10(HR) and Mextra1984H(HL) both influenced by the nitrogen chelating extractant and another acidic cation exchange extractant, for zinc, cadmium metal ions, it was found that in the extraction reaction, it is greatly influenced by pH, which shows that it was mainly a cation exchange reaction, only in this time when the agents were as organic acids. The slope Analysis of synergistic extraction of nickel extraction system was obtained, the reaction equation for nickel metal ions can be expressed as Ni2++(1/2)(HR)2+HL=NiRL+2H+, with the same slop analysis, the extraction reaction equation of zinc can be also expressed as Zn2++(1/2)(HR)2+HL=ZnRL+2H+. It was found that the value of△H is positive according to the temperature mechanism analysis, which reflects the synergistic extraction process for the extraction of metal ions is an endothermic reaction. So the Elevated temperature favors synergistic extraction system on the extraction of metals. The synergistic system Versatic10/Mextra1984H extraction kinetic mechanism was researched, and it was found that the enhancement of the stirring rate cannot introduce the enhancement of the extraction rate. However, the increasing temperature and concentration of each extractants was found to increase the extraction speed of each metal ions, which indicates that this reaction is controlled by the chemical reaction mechanism. |
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