A furnace start-up method for preparing elemental metal or alloy by molten salt electrolysis

Abstract

The invention discloses a furnace starting method for preparing simple substance metal or alloy in a molten salt electrolysis mode. The furnace starting method includes the following steps that a furnace starting electrode and an electrolysis electrode are fixed to a conducting bar side by side simultaneously, the distance from the electrolysis electrode to the bottom of a graphite crucible is larger than the distance from the furnace starting electrode to the bottom of the graphite crucible after fixation, and the conducting bar is installed on an electrode lifting device; the tip end of the furnace starting electrode makes tight contact with the bottom of the graphite crucible but makes no contact with the edge of the graphite crucible, and solid electrolyte is added into the graphite crucible gradually; an alternating voltage-stabilizing power source is started to heat the electrolyte and enables the electrolyte to become liquid; the furnace starting electrode is taken out, and the electrolysis electrode is kept; and an electrolysis power source is started, the electrolyte is added to adjust the composite of molten salt electrolyte, and electrolysis is carried out. The furnace starting method is stable in performance in the furnace starting stage, operation is easy, and the operation in the switching process of furnace starting and electrolysis is convenient.

Description

technical field [0001] The invention belongs to the technical field of electrolysis, in particular, the invention relates to a furnace start-up method for preparing elemental metal or alloy by molten salt electrolysis. Background technique [0002] When preparing elemental metals or alloys by molten salt electrolysis, the electrolyte needs to be heated to melt before electrolysis, and then the formal electrolysis process can be carried out. At present, there are three main methods of heating and starting the furnace: (1) external heating method, that is, external heating devices and equipment are arranged outside the molten salt electrolytic cell. This method makes the entire electrolytic cell including the external heating device larger in volume, The external heating efficiency is not high, and the energy loss is relatively large; (2) Built-in electrode heating method, that is, electrodes specially used for heating are arranged inside the electrolytic cell. Generally, the ...

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Problems solved by technology

At present, there are three main methods of heating and starting the furnace: (1) external heating method, that is, external heating devices and equipment are arranged outside the molten salt electrolytic cell. This method makes the entire electrolytic cell including the external heating device larger in volume, The external heating efficiency is not high, and the energy loss is relatively large; (2) Built-in electrode heating method, that is, electrodes specially used for heating are arranged inside the electrolytic cell. Generally, the heating electrode and the electrolytic electrode cannot be used in common, which makes the structure of the electrolytic cell more complicated. , which brings an additional burden to the design and preparation of the electrolytic cell; (3) the arc heating method, although this method is more flexible

However, in the traditional arc starting heating method, there are problems such as that the furnace start-up electrode needs to be equipped with a lifting device and a conductive cable, which is inconvenient to move, and if the conductive cable has insulation skin during the furnace start-up process of a high-power electrolytic cell, it will be seriously heated, and it is unsafe without insulation skin.

The Qinghai Salt Lake Institute of the Chinese Academy of Sciences improved the traditional arc starting method in the process of electrolytically preparing magnesium rare earth alloys. The furnace starting electrode was directly installed at the position of the electrolysis electrode to start the furnace, which saved the need for cables for starting the furnace and reduced unsafe factors. , but when switching to electrolysis at the end of the furnace start-up stage, due to the high temperature of the graphite electrode and the electrolysis furnace, and the heavy weight of the electrolysis electrode used in the electrolysis stage, it is very difficult to replace, which brings inconvenience to operation

[0003] Existing furnace start-up methods have different degrees of defects. The heating efficiency of the external heating method is not high, and the energy loss is relatively large. The structure of the electrolytic cell of the built-in electrode heating method is relatively complicated. The traditional arc-starting heating method requires an additional lifting device for the start-up electrode. And conductive cables, it is inconvenient to move, and in the process of starting the furnace of the high-power electrolytic cell, if the conductive cable has serious insulation skin heating, it is unsafe without insulation. The temperature of graphite electrodes and electrolysis furnace is too high, and the electrolysis electrodes used in the electrolysis stage are too heavy, so it is very difficult to replace them

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