Method for preparing calcium tungstate from chloropyridine tar

The invention discloses a method for preparing calcium tungstate from residue tar of chloropyridine, and belongs to the field of reclamation of organic residue in fine chemical engineering. In a process of preparing pyridine chloride, the residue obtained by after-treatment contains deactivated tungsten hexachloride, pyridine perchloride, pyridine-N-oxide, coke, pyridine polymer and the like, andhigh-purity calcium tungstate is obtained by performing neutralization, discoloration and calcium tungstate precipitation. The process is simple and easy in operation, realizes cyclic utilization of tungsten resources, and avoids waste of the tungsten resources and contamination to the environment, the recovery rate of tungsten of the process is as high as 95% and above, and the process has huge economic benefits and social benefits. 本发明公开了种利用氯代吡啶釜残焦油制备钨酸钙的方法，属于精细化工中有机釜残再生回收领域。在制备吡啶氯化物过程中，后处理得到的釜残，包括失活六氯化钨、过度氯化吡啶物、吡啶氧化物、焦炭、吡啶聚合物等，经过中和反应、脱色、钨酸钙沉淀得到高纯钨酸钙。本工艺简单易操作，实现钨资源的循环利用，避免钨资源的浪费及对环境的污染，本发明工艺钨的回收率高达95％以上，具有巨大的经济效益和社会