A kind of method of preparing aluminum benzoate from calcium-free chromium slag

Abstract

The invention discloses a method for preparing aluminium benzoate from calcium-free chromium slag. The method comprises the following steps: (1) crushing calcium-free chromium slag; (2) adding water and leaching the chromium slag, and standing the leaching solution for the future use; (3) reducing hexavalent chromium in the leaching solution to trivalent chromium precipitates; (4) separating iron precipitates and aluminium precipitates from the chromium slag treated in the step (2); separating aluminium solution from the precipitates in the step (4); (6) adding ammonium benzoate solution in the aluminium solution obtained in the step (5), so as to generate aluminium benzoate. The method disclosed by the invention is capable of detoxicating the chromium slag containing hexavalent chromium, and converting the contained aluminium to another aluminium benzoate with a higher added value, thus turning harm into good, and turning waste into wealth.

Description

technical field [0001] The invention belongs to the technical field of comprehensive utilization of chromium slag, and in particular relates to a method for preparing aluminum benzoate from calcium-free chromium slag. Background technique [0002] Chromium salt is an important inorganic salt product. In recent years, under the guidance of relevant government departments, the manufacturers of chromium salt in my country have adopted technological transformations. Most of them adopt calcium-free roasting process, although the chromium residue is reduced compared with calcium roasting process. However, the chromium slag produced still contains hexavalent toxic chromium salts, the main components are MgO70-80%, CaO0.5-1.0%, Fe 2 o 3 6~12%, SiO 2 3~7%,Al 2 o 3 3~5%,Cr 2 o 3 0.2~2%, of which Cr 6+ 0.2~0.5%. Due to its strong toxicity due to the excess water-soluble Cr(Ⅵ), chromium slag is one of the 47 most dangerous wastes recognized internationally and is listed as a nati...

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Problems solved by technology

However, whether it is used as an additive for cement production or as a sintering agent for steelmaking, it needs to be processed in cooperation with relevant manufacturers. During the processing process, due to problems such as chromium slag transportation, addition process, and cost, the cooperative manufacturers are not active, and the reduced chromium slag Can not be disposed of in a timely and sufficient amount, resulting in an increasing stockpile of chromium slag in chromium salt manufacturers, causing increasing pressure on the environment

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