The use of bismuth to smelt low-grade ferroalloys began around 1860. Later, ferromanganese smelting with blast furnace and ferrosilicon containing less than 12% silicon were developed. Iron alloys were produced in France using electric arc furnaces between 1890 and 1910. H. Moissan used the electric arc furnace to systematically test the difficult-reducing elements. E. (PLTHâ–¡roult) was used in industrial production. At that time, coke and charcoal were used as reducing agents to reduce the ore. Most of the products were high-carbon. of. After 1920, in order to meet the needs of the development of high-quality steel and stainless steel, the new stage of production of low-carbon ferroalloys began.
On the one hand, based on the process of metal preparation by Aluminium Thermal Method proposed by K. Goldschmidt in 1898, the development of aluminothermic method for the smelting of some carbon-free iron alloys and pure metals; A desiliconization refining method for oxidizing a silicon-containing alloy in an electric furnace. Since the production cost of the aluminothermic method is too high, the desiliconization refining method has been applied more. Until now, medium carbon, low carbon, micro carbon ferrochrome, medium carbon, low carbon ferromanganese, metal manganese is still mostly refined by this method. The heat exchange method of refining ferrochrome is to further accelerate the reaction by heating the ore, lime melt and silicon chromium alloy by heat-mixing, which is a further development of the desiliconization refining method. In addition, pure alloy additives (such as manganese metal) are produced by electrolysis, and ultra-fine carbon ferrochrome with extremely low carbon content is produced by vacuum decarburization. In recent years, a method of refining ferrochrome and ferromanganese by pure oxygen blowing has also been developed.
China produced ferrosilicon and ferromanganese in small electric furnaces around 1940. In 1955, the Jilin Ferroalloy Plant began mass production. Subsequently, a number of ferroalloy plants were built in various places, and ferromanganese was produced using small blast furnaces to meet the needs of the national steel industry.
Teapot is a kind of mouthed utensil for making and pouring tea. It is a kind of tea set, mainly used to make tea. The teapot is composed of a lid, a body, a bottom and a ring foot. The lid has holes, buttons, seats, covers and other details. The pot body has mouth, extension (lip wall), mouth, flow, abdomen, shoulder, handle (handle, wrench) and other parts. Because of the subtle differences in the handle, lid, bottom and shape of the teapot, there are 200 basic shapes of the teapot. When making tea, the size of the teapot depends on the number of tea drinkers. Teapots have a lot of texture, most of which are made of purple clay or porcelain.
Teapot Kettle,Red Teapot Kettle,Teapot And Kettle,Ceramic Teapot Kettle
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