Molten salt system for electrolytic magnesium oxide, preparation method and application thereof

Abstract

The invention discloses a fused salt system for electrolytic magnesium oxide as well as a preparation method and an application thereof. The method comprises the following steps that firstly, a basicprecursor is prepared with, by mass, (50-99)%:(1-50)% MgF2 and CaF2, and then an intermediate fused salt system is prepared through mixing LaF3 which accounts for, by mass, 1-10% of the mass of the basic precursor and the basic precursor; and the fused salt system for the electrolytic magnesium oxide is prepared through mixing LiF which accounts for, by mass, 10-30% of the total mass of the intermediate fused salt system. The fused salt system has good electrochemical performance, stability and magnesium oxide solubility; the electrochemical performance of the system cannot be greatly fluctuated, the appropriate melting points, density, viscosity, conductivity and the initial crystal temperature of an electrolyte can be kept, the requirements of dissolution and continuous electrolysis of the magnesium oxide can be satisfied conveniently, so that high-purity magnesium metal can be obtained; and the fused salt system can realize the continuous electrolysis of the magnesium oxide at a lower temperature, achieve the energy-saving and consumption-reducing effects, facilitate large-scale industrial production, reduce obviously the production cost, and save energy sources.

Description

technical field [0001] The invention belongs to the technical field of molten salt for electrolysis, and in particular relates to a molten salt system for electrolytic magnesium oxide, a preparation method and an application thereof. [0002] technical background [0003] Magnesium is one of the ten most widely distributed elements in nature, with abundant resource reserves and wide distribution. Due to the strong chemical activity of magnesium, most magnesium exists in the form of compounds in nature. Therefore, metal magnesium needs to be prepared by different methods. At present, the commonly used methods for the preparation of metal magnesium include electrolytic method and silicothermal method. [0004] The existing electrolytic method usually obtains metallic magnesium by electrolyzing magnesium chloride, and obtains metallic magnesium by electrolytically melting anhydrous magnesium chloride under high temperature conditions. However, the magnesium chloride electrolys...

AI Technical Summary

Problems solved by technology

However, the magnesium chloride electrolysis method has the following defects: the production process of the anhydrous magnesium chloride is difficult to control, resulting in incomplete dehydration of the prepared magnesium chloride and affecting the subsequent electrolytic production; the dehydration of the magnesium chloride containing water requires higher temperature and acidic atmosphere, and consumes a lot of energy. 1. Serious corrosion of equipment; a large amount of waste water, waste gas and waste residue will be generated in the production process of magnesium chloride, which will pollute the environment; chlorine gas generated by electrolysis of magnesium chloride needs to be properly collected and stored, and once leakage occurs, it will cause very serious consequences

The literature ("Study on the channel type and process of direct electrolysis of magnesium oxide to produce metal magnesium" Sha Luchang, Cai Anhong) discloses a process for producing metal magnesium by electrolysis of magnesium oxide, using MgF 2 -LiF molten salt system dissolves MgO, the disadvantage of this process is: the solubility of MgO is small, and the use of MgF 2 -The electrolyte of LiF is a molten salt system is unstable, electrolysis cannot be continuous, the product has high impurity content, low current efficiency, and high energy consumption per unit product