Process method for melting battery negative electrode mixed rare earth metal in induction melting furnace
 1. Technical Field:
 A mixed rare earth metal with low zinc and low magnesium is used as a raw material and an alkali metal chloride is used as a protective agent to melt the mixed rare earth metal on a negative electrode of a battery in an induction melting furnace, which belongs to the field of metallurgical technology.
 2. Background technology:
    At present, the mixed rare earth metal of the negative electrode of the battery is made of low-zinc and low-magnesium grouped rare earth chloride as the raw material, using 2000A of electricity
The process parameters (current, voltage, temperature, electrolyte concentration) of each electrolysis system produced by the solution tank are not the same, and the grouped rare earth chloride cannot achieve the complete content of the ingredients between each batch during the production process. Unanimous. Due to the limitation of the production process conditions of raw materials and equipment capacity, the content of lanthanum, cerium, praseodymium, and neodymium in the product fluctuates greatly, especially lanthanum is the most serious, which will directly affect the service life of the end product nickel-hydrogen battery.
3. Content introduction:
    The purpose of this method is to provide a process method for melting the mixed rare earth metal on the negative electrode of the battery using an induction melting furnace,
It is an element that stabilizes the mixed rare earth metal of the negative electrode of the battery, and uses the binary mixed salt of potassium chloride and sodium chloride as protection
The covering agent can prevent the oxidation loss of rare earth metals, and achieve a uniform proportion of elements in the mixed rare earth metal products.
To.
 The process method of the induction melting furnace to melt the mixed rare earth metal of the negative electrode of the battery is in a non-vacuum open system
It uses low-zinc and low-magnesium mixed rare earth metals as raw materials, uses potassium chloride and sodium chloride binary mixed salt protective covering agent, and uses high-purity alumina ceramic crucibles as smelting containers to melt the battery negative mixed rare earth metals. In the ingot process, a split type bottomless ingot mold is used. After heating and melting the binary mixed salt of potassium chloride and sodium chloride, slowly add a prescribed batch of low-zinc and low-magnesium mixed rare earth metals, and after melting, the stirring force of the induction melting furnace is used to make the liquid rare earth metals mix fully and evenly. The smelting temperature is 850-950℃, the smelting time is 20-40 minutes, and the ratio of the mixed rare earth metal to the protective covering agent is 3-5:1, so that the internal composition of the product is uniform. Reduce vacuum equipment and reduce equipment investment. The smelting vessel and the induction melting furnace are sintered with quartz sand between the induction coil and the crucible to protect the furnace body and crucible, and 3-5% boric acid is added to the quartz sand to increase the density of the furnace lining. The protective covering agent adopts the binary mixed salt of potassium chloride and sodium chloride, which can reduce the melting temperature. When the mixed rare-earth metal ingot is cast, it ensures the good appearance of the rare-earth metal ingot and reduces the loss of the rare-earth metal during the melting process. In the ingot casting process, a split bottomless ingot mold made of heat-resistant steel is used. After the casting is completed, after the temperature of the rare earth metal is reduced, take the
The lower ingot makes it easy to demould the rare earth metal, and the bottomless ingot mold has a long service life, and at the same time reduces the labor intensity.
    The production process of the mixed rare-earth metal of the negative electrode of the battery by the induction melting furnace of this method is simple and convenient for the user's production operation. The content of the internal components of the rare-earth metal products is consistent, which is beneficial to the ratio of raw materials in the production of nickel hydrogen powder, and the investment in rare earth metal equipment is small. It is easy to install and maintain, the product contains low non-rare earth impurities, and the product quality is stable, thereby improving the performance of the nickel-hydrogen battery, and the quality of the product after melting can fully meet the requirements of users.
4. Specific implementation methods:
    The best embodiment of the process of melting the mixed rare earth metal on the negative electrode of the battery by the induction melting furnace of this method:
    Raw material: 197 tons of low-zinc and low-magnesium mixed rare earth metals
    KCI-NaCI=18 tons of mixed salt
    Equipment: GW-0. 5T intermediate frequency ironless induction melting furnace
    Production process: Put 20-25Kg=yuan mixed salt (industrial-grade Baotou production) into each furnace, and add it after melting
Into 250-255Kg low-zinc and low-magnesium mixed rare earth metal (produced in Baotou), the power of the induction melting furnace is adjusted to about 100KW, and the temperature
Keep it at 850-950℃, smelt for 20-30 minutes, and let it stand for 5 minutes. After the internal composition is fully uniform, proceed
Furnace, casting operation, use a stainless steel spoon to take out the metal and cast it in the bottomless 42CrMo material ingot mold, and then proceed to the next
One furnace of smelting operation, after the metal is cooled, it is demoulded, cleaned, and polished. After the analysis and inspection are qualified, it is packaged into
For the final product.
    Test result: The product is 194.35 tons of mixed rare earth metal in the negative electrode of the battery, and the power consumption is about 420Kw. h/t, analysis
The test results show that the internal composition of the product after melting is uniform and stable, and the non-rare earth impurities do not exceed the standard.
The content of the ingredients in the product is uniform.
Analysis results of five pieces of rare earth metals taken in the same batch before melting (%) Table 1