PREPARATION OF PURE FERRIC CHLORIDE FROM HYDROCHLORIC ACID SOLUTIONS BY SOLVENT EXTRACTION

The present invention relates to a field of preparing high-purity ferric chloride from hydrochloric solutions containing impurities. More specifically the invention concerns a ferric iron extraction from water solutions as a result of concentrated hydrochloric acid interaction with iron-containing concentrates, as a result of multi-stage extraction of ferric chloride from solutions of complicated composition and due to processing of industrial wastes, including spent etching solutions of metallurgical plants after chlorination. The essence of the invention is that the proposed method includes two stages of concentration, extraction, and stripping steps. As an extracting agent use is made of aliphatic alcohol, predominantly octanol-1, octanol-2, 2-ethylgexanol, and decanol-1 or their mixtures. The alcohol content in organic phase is up to 100 %. Attained technical result consists in obtaining high-purity ferric chloride solution with not less than 300 kg/m3 FeCl3 concentration. Ferric chloride recovery is 96-98 % irrespective of the nature of impurities present in a feed hydrochloric solution concurrently with the limitation of waste solutions and optimization of material flows and equipment used. The resulting ferric chloride solutions are feasible for further processing in high performance installations of spray roasting which permit combine in one process receiving of high-purity ferric oxide and regenerated hydrochloric acid of high concentration. L'invention porte sur un procédé de préparation d'une solution de chlorure ferrique de haute pureté à partie de solutions chlorhydriques contenant des impuretés, et plus spécifiquement sur l'extraction de fer ferrique de solutions aqueuses résultant de l'interaction d'acide chlorhydrique concentré et de concentrés contenant du fer résultant de l'extraction en plusieurs étapes de chlorures ferriques de solutions de composition complexe de rejets industriels traités, dont des solutions usées de décapage provenant d'usines métallurgiques ayant subi une chloration. L'essentiel de l'invention repose sur fait que le procédé proposé comporte deux étapes de concentration, extraction, et désorption. On utilise comme agent d'extraction un alcool aliphatique principalement de l'octanol-1, de l'octanol-2, 2-éthylgéxanol, et du décanol-1 ou leur mélange. La teneur en alcool de la phase organique peut atteindre 100 %. L'objectif atteint est l'obtention d'une concentration d'au moins 300kg/m de FeCl3 quelque soit la nature d