Tween80,-(nh <sub> 4 </ Sub>) <sub> 2 </ Sub> So <sub> 4 </ Sub>-h <sub> 2 </ Sub> O System Of Trace Cadmium In The Zinc-based Enrichment Of Trace,

Zinc and Cadmium are the elements of group II B,With the similar character, Zinc is useful to boady,While cadmium is toxin. The separation of Zinc and Cadmium are often problem as Cobalt and Nickel in hydrometallurgy, environmental protect and analytical chemistry.Liquid-solid extraction system based on polymer-salt-water is a new kind of extraction and separation system developed only in the recently years. In the presence of inorganic salts, polymers solution can be separated into liquid and solid phases and the extracted matter slectively distributes in two phases, based on the difference of the distributes ratio of matter, thus extraction and separation will be realized with some conditions controlled. Compared with the traditional methods, this one has the advantage of convenient operation, high extractability and innocuity of reagents. Therefore, it is a vast useful separation technology.The separation and concentration of Cd( II ) from Zn matrix using Tween80-salt-water extraction system were studied.Through continuous explorations and experiments, at last, optimized experiment conditions were decided. The extraction rate of Cd surpassed 98%, The main jobs are as follows:1. The paper discusses the elements influencing the phase diagram, and polymers solution was separated into two phases in polymer-salt-water system, such as the concentration of polymer, the concentration and the kinds of inorganic salts, molecules mass of polymer, acidity of solution and so on.2.The distribution behavior of Cd(II), CV and KI in the Tween80-ammonium-water extraction system has been investigated. The factors which affect extraction such as acidity of solution, the amounts of chromo-tropic reagents and salt were analyzed.Mixing separation experiments of Cd(II) were carried out in different amounts of Zn( II).3. The paper determines the best extraction and separation condition, that is, 3.0mL4.5moL/L H₂SO₄ solution, 2.0mL30% KI solution, 1.0mL0.24% CV solution, complex stable ions add 10mL30% Tween80 solution, the total bulk of fixed system is 25mL, add 6g ammonium, polymer solution was separated two phase.the system hassuccessfully separated Cd (II) from Zn matrix.4. Mechanism of extraction was studied basically. The composition of Cd( II) and CV and KI in Tween80 was determinated by molar ratio method.lt was believed that metal ion extraction in liquid-solid extraction system is the result of complexation reaction, electrostatic effect and hydrogen bonding and hydrophobic bonding.5.The research explores a complex spectrophotometric method based on extraction for determination of trace Cd(II) in Tween80-(NH4)2SO4-KI-CV extraction system and the use of PVA-OP-SCN'-RhB system for determination of trace Zn( II), the best experiment condition were obtained.6. On the basis of fuzzy control theories and experimented data, the predictive model is established about the relationships between the factors which affect extraction and determination of trace Cd(II) such as acidity of solution, the amounts of chromo-tropic reagents, the concentration of salt and polymer;Use the model, the factors can be predicted at the term of examination data, the best condition of extraction and determination of trace Cd( II) were obtained. The results shows that the predictive model and the experiment have the deviation within the -4⁺4% limits, the predicted values were well consistent with the experimented ones.