Study On Foundational Ion Exchange Properties And Its Application Of Potash Feldspar

This paper studies the thermodynamics and kinetics of the ion exchange reaction between the potassium ions from potash feldspar and the sodium ions from solutions. With different reaction temperatures that is from 1123K to 1273K thermodynamic analyses demonstrate the feasibility of the ion exchange reaction because the values of â–³Gt0 are totally negative and the exothermic reaction because the values of â–³Ht° are totally negative .Ion exchange kinetic models that are composed of two controlled steps are established to represent the relation of the reaction velocity with the reaction temperature and time, While inner diffusion become rate-determining step, apparent activation energies is around 38.06kJ/mol, then chemical exchange became rate-determining step , and apparent activation energies turn into around 129.69 kJ/mol. Since chemical exchange becomes rate-determining step at the end of the ion exchange reaction, an experimental ion exchange kinetic equation is work out on the basis of the second-order kinetic model.At the extraction potassium from potash feldspar with phosphorite in the acid environment, the relatively perfect experiment conditions of the potassium leaching rate are confirmed as follow, material ratio(weight) m(phosphorite) : M(potash feldspar) =0.8:1, phosphorus acid : 3mL/g phosphorite, concentration of the phosphorus acid 49%P₂O₅, temperature 150℃, time 2.5h; the relatively perfect experiment conditions of the phosphorine leaching rate are confirmed as follow, material ratio(weight) m(phosphorite) : M(potash feldspar) =0.8:1, phosphorus acid : 4.5mL/g phosphorite, concentration of the phosphorus acid 44%P₂O₅, temperature 120℃, time 2.5h. Experimental non-soluble results of characterization by X-ray diffraction ( XRD ) ( FTIR ) and ( Raman ) show that there are two theories coexistent: one is that potassium extraction by ion exchange reaction, then the other is that HF dissociates potash feldspar; thermodynamic analyses demonstrate the feasibility of the ion exchange reaction with experimental temperature, which firmly demonstrates the mechanism; the direction of fluoric ions that originally exists in the phosphorite are studied by X-ray diffraction ( XRD ) and chemical analysis, and the experimental results show that fluoric ions are totally consisted in the non-soluble fluorine silicate.Finally, compared with the effects of different surfactants on the operation conditions, and experimental results show that cationic surfactant which absorb on the surface of potash feldspar have the best adaptable with potash feldspar, as a result while the dosage is 500g/t, so the value of the potassium leaching rate has an increase about 8.26; anionic surfactant have a good adaptability with potash feldspar, as a result while the dosage is 500g/t, so the value of the potassium leaching rate has an increase about 7.00; amphiprotic and non-ionic surfactant had a bad adaptability with potash feldspar as it did not effectively affected the potassium leaching rate. Mixed surfactant has a better potassium extraction degree than single surfactant, as a result while the dosage is 500g/t as well as the weight ratio of the cationic surfactant and the anionic surfactant is 3:1 , so the value of the potassium leaching rate has an increase about 8.62.