Method for separating chromium ions and iron ions in multicomponent solution

Abstract

The invention provides a method for separating chromium ions and iron ions in a multicomponent solution, comprising the following steps of: with a mixed solution of chromic sulfate and ferric sulfate, generated by leaching out chromite by using sulfuric acid, as a raw material, adding an extractant to carry out extraction; obtaining an inorganic phase of a chromic sulfate solution and obtaining organic phases of the extractant and the ferric sulfate after extraction; then carrying out back extraction on the organic phases by using a sodium hydroxide solution and regulating a pH value to be 9-10 to obtain ferric hydroxide, a sodium sulfate solution and an extractant; recycling the extractant, and preparing the chromic sulfate by utilizing the extracted chromic sulfate solution and adopting a direct crystallization method; and preparing iron oxide red pigment by utilizing the ferric hydroxide as a raw material through a high-temperature crystallization method. Compared with the traditional technology for removing iron from the mixed solution of the chromic sulfate and the ferric sulfate, the invention has the most remarkable advantages that a process flow is short without three waste emission and extractant is recycled. Iron oxide red as a by-product does not contain hexavalent chromium and can be applied to industries of buildings, coatings, vehicles and the like.

Description

technical field [0001] The invention belongs to the technical field of mineral processing, and relates to the processing technology of chromite, in particular to a method for separating chromium ions and iron ions in a multi-component solution. Background technique [0002] At present, the preparation process of chromium salt mostly uses chromite as raw material, adopts calcification roasting process, not only the process is long, but also a large amount of Cr 6+ waste, and this waste has been listed as the top priority of solid waste management by countries all over the world. However, the process of preparing chromium salt by sulfuric acid method is affected by the separation of chromium and ferric ions in the solution, which limits the technology of preparing chromium salt by sulfuric acid method. The separation techniques of chromium ions and iron ions in the solution are as follows: [0003] (1) Ferrous sulfate crystallization method. Chromium sulfate and ferric sulf...

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Problems solved by technology

[0002] At present, the preparation process of chromium salt mostly uses chromite as raw material, adopts calcification roasting process, not only the process is long, but also a large amount of Cr 6+ waste residue, and this waste residue has been listed as the top priority of solid waste management by countries all over the world

However, in the process of preparing chromium salt by sulfuric acid method, it is affected by the separation of chromium and ferric ions in the solution, which limits the technology of preparing chromium salt by sulfuric acid method.

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