| Leaching selenium technology from Ni-Mo ore smelter dust has been studied on thermodynamics and dynamics view in paper. The feasibility and scientificity of leaching selenium from Ni-Mo ore smelter dust by oxidant in complex system of HCl-H2SO4 has been proved on theory; Meanwhile, reducing Se technology from lixivium of Ni-Mo ore smelter dust has been investigated on thermodynamics view in paper.The extracting selenium technology from Ni-Mo ore smelter dust has been determined Through experimental study. Namely, leaching selenium from Ni-Mo ore smelter dust by oxidant in complex system of HCl-H2SO4; Under reducing Se conditions, reducing Se powder from leaching solution by sodium sulfite, As and Se has been separated from solution of high selenium the arsenic effectively, selenium powder of industry grade has been developed. This leaching Se craft overcame disadvantage of plenty dust?low recovering rate for Se?the energy consumption high?producing SO2, SeO2 and As2O3 easily and so on noxious gas, There is positive function to improve environment of work and reduce environmental pollution of noxious gas. The advance of process have been showed, realizing goal of cleanly?environmental protection?energy conservation.In technological research of leaching selenium from Ni-Mo ore smelter dust,according to material characteristic adopting complex system of HCl-H2SO4?making use of strong oxidability of sodium chlorate, the process of leaching selenium from Ni-Mo ore smelter dust has been strengthened and the efficiency and leaching rate of leaching Se has been improved. It is useful to reduce production cost in the industrial application.The process of reducing Se has been studied in lixivium of high As and Se from Ni-Mo ore smelter dust. Se powder has been reduced by sodium sulfite under experimental conditions; As is mainly remained in being reduced solution, As and Se has been separated completed.The optimum technological conditions of leaching Se from Ni-Mo ore smelter dust has been determined through experimental study. The leaching of selenium reached 98.97%at 95?and stirring speed of 350 rpm for 150 min with the particle size of-0.15 mm, initial [H+] concentration of 8 mol/L, the solid/liquid ratio of 1:5 g/mL and the coefficient?of 4.5, mole ratio of HC1 to H2SO4 of 3:2 and adding speed of sodium chlorate of 35 mgmin-1; The technological conditions of reducing Se from lixivium of Ni-Mo ore smelter dust has been determined. The rate of reducing Se is more than 99%at 80?and stirring speed of 400 rpm for 120 min with the initial [H+] concentration of 3.5 mol/L and coefficient (3 of adding sodium sulfite of 10. Se powder that has been developed contains 99.684% Se, it fits standard of Se-3 of GB1477-79. The rate of recovering Se is 95.79%in whole process of extracting Se from Ni-Mo ore smelter dust,.The kinetics model of leaching selenium from Ni-Mo ore smelter dust was established as 1-(1-?)1/3=185.4exp(-44400/RT)t through dynamics study; The apparent activation energy of leaching selenium was determined to be 44.393 kJ/mol, It can infer that the process of leaching Se is controlled by the surface chemical reaction.The waste liquid of extractinging Se must be dealed with before discharge because there is plenty of acid and As in waste liquid. The traditional craft are neutral by alkali?precipitation arsenic and fixed As. It will certainly consume massive alkali for high acid in waste liquid and acid cannot be recycled to comprehensive utilization. In this research, acid in waste liquid is separated and recycled using anion exchange membrane by diffusion dialysis, recycled acid is returned to leach Se from Ni-Mo ore smelter dust. The goal is realized to reduce alkali consume and utilize resources comprehensive.The process of separating H+from waste liquid after reducing Se has been studied using anion exchange membrane by diffusion dialysis in research. Through the experiment of static state diffusion dialysis, average diffusion velocity of H+and separating coefficient of acid to salt have bee investigated in 3# anion exchange membrane;The mathematical model of H+and Na+between diffusion velocity and diffusion time have been infered under the conditions of static state diffusion dialysis, the mathematical model are y=3.188x-0.1242?y=0.3355x-0.1854, respectively. In experiments of dynamic diffusion dialysis, H+diffusion mass-transfer coefficient has been investigated at different experimental temperature; The mathematics relationship between H+diffusion mass-transfer coefficient U and temperature has been studied at temperature range of 15??t?35?, The mathematics expression is U=0.0195t+0.522. In diffusion dialysis experiment of one time pass, effect of material fluid flux on diffusion dialysis and the ratio of water flux to material fluid flux on diffusion dialysis have been investigated; Under experimental conditions of material fluid flux of 81ml/h and the ratio of water flux to material fluid flux of 1.2, recovery percent of H+and retention percent of As are 35.16%and 92.49%,respectively. In order to realize the entire craft continuity of extracting Se from Ni-Mo ore smelter dust, the process of removing As from waste liquid after extracting Se has been studied in research, the mechanism of removing As by oxidation coagulation has been studied and the optimum technological conditions of removing As from waste liquid has been determined through experimental studies, waste water after being disposed fits to the national emission standard.In brief, it can avoid serious pollution to environment of As and Se from Ni-Mo ore smelter dust on environmental protection view.on the other hand, Se in Ni-Mo ore smelter dust can be recovered on resources comprehensive utilization view through topic's research. This research craft is advanced, saving energy and protecting environment, the theory for its industrial application can been provided, it have important social efficiency and economic efficiency. |
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