多级盐田滩晒硝酸钠矿浸取液时浓度分布模型及优化

天然硝酸钠矿浸取液在进行多级盐田日晒除盐时,各级盐田中目标产物硝酸钠浓度的分布及盐田的级数对硝酸钠收率有很大影响。本文通过物料衡算和相图推导,建立了以硝酸钠收率为函数,以盐田级数、各级浓度分布为自变量的数学模型, 并结合实际生产数据,以硝酸钠在盐田中的损失量为目标函数,利用MatLab优化工具进行优化。研究结果表明:盐田级数越多,硝酸钠的损失越少,但四级以后,损失减少不大,综合考虑确定天然硝酸钠矿浸取液应采用3-4级盐田滩晒,同时获得了不同盐田级数时卤水浓度分布规律;如果各级盐田中沉积盐夹带液相量比例相同,则该比例大小对各级盐田中的浓度、析盐量和蒸发量分布没有影响,但对硝酸钠收率的影响很大。

Optimization of and modeling of concentration distribution of the solution obtained by leaching of natural sodium nitrate ores in the sunning process

When the solution obtained by leaching of natural sodium nitrate ores in Xinjiang Lop Nur, is evaporated in the sunning process, NaCl and Na2SO4 are crystallized and separated, and the recovery ratio of NaNO3 is greatly effected by the number of solar ponds and the concentration distribution in these solar ponds. In this paper, the model, in which the recovery ratio of NaNO3 is function and the number of solar ponds and the concentrations in these solar ponds are independent variables, has been established by material balance and phase diagram calculation. Combining with industrial data, utilizing the optimizing method of MatLab, the model has been optimized. The study showed: with the increase of the number of solar ponds, the loss of NaNO3 is decreased, but the decrease is small when the number of solar ponds is 4 or more, as a result, the number of solar ponds should be 3 or 4 for the sunning process of solution obtained by leaching of natural sodium nitrate ores. The rule of concentration distribution in solar ponds has been obtained; if the ratios of the quantity of the brine carried by salts to salts were equal, the value of this ratio didn't effect distributions of concentrations, quantities of salts crystallized and evaporation quantities in solar ponds, but effected the loss of NaNO3 greatly.