Abstract: A method for directly preparing a trivalent chromium compound by electrochemical oxidation of ferrochrome is provided. The method includes: putting ferrochrome as an anode, and placing the anode into an electrolyte solution containing a complexing agent together with a cathode, then turning on a power supply for electrolysis reaction so that chromium and iron in ferrochrome are directly converted into free Cr3+ and Fe3+ respectively, allowing one of Cr3+ and fe3+ to form a stable soluble metal complex together with the complexing agent, and allowing the other of Cr3+ and Fe3+ to form a metal hydroxide solid together with OH? generated by electrolysis reaction, so as to obtain an electrolysis completion slurry. Compared with the prior art, the present application has no hexavalent chromium salt stage, thereby shortening the process flow and avoiding the generation of chromium-containing waste residue.

Abstract: A method and a device for preparing a trivalent chromium salt by electrochemical oxidation of ferrochrome in an acidic system are provided. The method includes: putting ferrochrome as an anode and placing the anode into an acidic electrolyte together with a cathode, and then turning on a power supply for electrolysis reaction, until an electrolysis completion solution containing the trivalent chromium salt and a trivalent iron salt is directly prepared. Compared with the prior art, the one-step electrochemical synthesis of the trivalent chromium salt solution can be achieved without a hexavalent chromium salt stage, avoiding the generation of chromium-containing waste residue, shortening the process flow and significantly improving the production efficiency of the trivalent chromium salt; furthermore, the reaction can be carried out at room temperature and normal pressure without the use of fine chromium iron powders and a high-concentration acidic electrolyte.

Abstract: A method for directly preparing a trivalent chromium compound by electrochemical oxidation of ferrochrome is provided. The method includes: putting ferrochrome as an anode, and placing the anode into an electrolyte solution containing a complexing agent together with a cathode, then turning on a power supply for electrolysis reaction so that chromium and iron in ferrochrome are directly converted into free Cr3+ and Fe3+ respectively, allowing one of Cr3+ and fe3+ to form a stable soluble metal complex together with the complexing agent, and allowing the other of Cr3+ and Fe3+ to form a metal hydroxide solid together with OH? generated by electrolysis reaction, so as to obtain an electrolysis completion slurry. Compared with the prior art, the present application has no hexavalent chromium salt stage, thereby shortening the process flow and avoiding the generation of chromium-containing waste residue.

Abstract: A renewable magnesium removing agent and its use in a preparation of a low-magnesium lithium-rich brine are provided. The magnesium removing agent includes a magnesium phosphate double salt of an alkali metal or ammonium. A regeneration of the magnesium removing agent is realized by adding the magnesium removing agent into Mg2+-containing chloride salt solution, wherein Mg2+ in the chloride salt solution and the magnesium removing agent are subjected to a magnesium removing reaction to form a solid-phase reaction product and carrying out a solid-liquid separation on an obtained mixed reaction product after the magnesium removing reaction is ended to separate the solid-phase material comprising a magnesium phosphate hydrate and then separating out a chlorine salt of the alkali metal or the ammonium from a remaining liquid-phase material, and finally carrying out a regeneration reaction on the magnesium phosphate hydrate and the chlorine salt of the alkali metal or the ammonium.

Abstract: A renewable magnesium removing agent and its use in a preparation of a low-magnesium lithium-rich brine are provided. The magnesium removing agent includes a magnesium phosphate double salt of an alkali metal or ammonium. A regeneration of the magnesium removing agent is realized by adding the magnesium removing agent into Mg2+-containing chloride salt solution, wherein Mg2+in the chloride salt solution and the magnesium removing agent are subjected to a magnesium removing reaction to form a solid-phase reaction product and carrying out a solid-liquid separation on an obtained mixed reaction product after the magnesium removing reaction is ended to separate the solid-phase material comprising a magnesium phosphate hydrate and then separating out a chlorine salt of the alkali metal or the ammonium from a remaining liquid-phase material, and finally carrying out a regeneration reaction on the magnesium phosphate hydrate and the chlorine salt of the alkali metal or the ammonium.