介绍了采用钾化焙烧和钠化焙烧工艺制备偏钒酸钾产品.通过实验室探索性试验得到较佳的偏钒酸钾制备工艺路线,即采用钾化焙烧工艺得到钒酸钾浸出液,经除杂后可制备聚钒酸钾,通过调整配入钾盐调整钾钒摩尔比为1∶1,经熔融、溶解、过滤及蒸发结晶得到满足纯度要求的钠含量较低的偏钒酸钾产品.
Dryingkinetics experiments ofbasic magnesiumchloride nanorods were performed, at different drying medium temperatures and different materiel bed- layer thickness. And the drying curves, the drying rate curves as well as the drying kinetics parameters were obtained. Then, the experimental data of drying kinetics for basic magnesium chloride nanorods were treated based on thin layer-drying models, to obtain the drying equation MR=exp [-(kτ)n],the drying rate equation-dMR/dτ =knMR(-1nMR)n-1/n, the drying rate constant k=Aexp[-Ev(1+CLL)/RT], the drying time index n=1.821 , the activation energy of interface evaporation Ev=11.228kJ/mol , the pre-exponential factor A =4.237min-1, and the experiential constant CL=55.556 m-1 were.
Approximate expressions for the temperature integral were reviewed,which had been used in the thermal analysis kinetics for many years.Error analysis of these approximations was carried out in the domain of 5≤ u ≤100.One approximate rational expression with higher precision was selected from rational approximations;and the other approximate exponential expression was also singled out from exponential approximations,which had a low precision compared with most of the rational approximations,but was very convenient to determine the kinetic parameters(activation energy E and frequency factor A).
