Method for deeply removing silicon and iron from chromite alkaline leachate

Abstract

The invention relates to a method for deeply removing silicon and iron from chromite alkaline leachate. The chromite alkaline leachate comprises leachate extracted from chromite by adopting a calcium-free roasting method and / or a liquid-phase oxidation method, a desiliconizing agent and a flocculating agent are sequentially added into the chromite alkaline leachate, after the reaction is completed, the silicon and iron are deeply removed through filtration, and the desiliconizing agent comprises a precipitator and calcium aluminate. According to the method for deeply removing the silicon and iron, a chemical precipitation-adsorption combined flocculating settling method is adopted, silicon and iron in the alkaline leachate can be deeply removed by controlling the desiliconizing agent and reaction conditions, and even the silicon and the iron can be deeply removed to 5 mg / L and 0.1 mg / L respectively; and in addition, the deep silicon and iron removal method not only is beneficial to solving the problem of smooth production of the chromium salt and providing guarantee on purity of the subsequently produced chromium salt, but also can ensure that the silicon content and the iron content of pseudo-boehmite products reach the standard.

Description

technical field

[0001] The invention relates to the field of chromium salt production, in particular to a method for deep removal of ferrosilicon from chromite alkaline leaching solution. Background technique

[0002] Chromium salt is an important basic raw material of inorganic chemical industry, and the main raw material for production is chromite ore. The chromium salt industry mainly adopts production processes such as calcium-free roasting method and liquid phase oxidation method. During the extraction process of chromium, most of the chromium, aluminum and vanadium in chromite will be converted into Na 2 CrO 4 , NaAlO 2 、NaVO 3 and other soluble sodium salt forms into the leachate. In addition, some aluminum, silicon and iron compounds will also enter the leaching solution and become the main impurities in the alkaline leaching solution.

[0003] In order to remove aluminum impurities, the method of neutralization and hydrolysis to remove aluminum is widely used i...