Calcining technology and calcining device for producing high-brightness and low-hardness talc by utilizing black talc

Abstract

Disclosed are a calcining technology and a calcining device for producing high-brightness and low-hardness talc by utilizing black talc. The calcining technology comprises the following steps: smashing and milling to enable grain fineness of a black talc raw material to be 150 to 8000 meshes; feeding the milled black talc raw material into the calcining device for calcining, wherein calcining temperature is 200 to 850 DEG C, and calcining time is 2 to 8h; and introducing high-concentration and high-pressure oxygen in a calcining process to form an oxidizing atmosphere, wherein oxygen concentration is 30 to 80 percent, and oxygen pressure is 0.05 to 0.7 MPa. The calcining device comprises a feeding mechanism, a rotary kiln and a discharging mechanism; a rotary cylinder of the rotary kiln is horizontally arranged rotatably, and comprises a feeding section, a heating section and a discharging section; the feeding section and the feeding mechanism are connected, and the discharging section and the discharging mechanism are connected; the rotary kiln comprises a combustor and also comprises an oxygen support ring, wherein the combustor is used for heating to calcine the powdery black talc raw material in the heating section, and the oxygen supply ring sheathes the feeding section, and is provided with an oxygen inlet and an oxygen chamber; a plurality of oxygen supply hoods are arranged in the rotary cylinder; and an oxygen hole is formed in each oxygen supply hood, and is in gas communication with the oxygen supply ring. According to the calcining technology and the calcining device disclosed by the invention, lower temperature calcination is performed under the oxidizing atmosphere, so that the talc does not produce phase change and is high in brightness.

Description

technical field [0001] The invention relates to the field of black talc mineral processing in nonmetallic ores, in particular to a calcining process and a device for producing talc with high whiteness and low hardness by using black talc as a raw material. Background technique [0002] Black talc is a general term for black and gray-black talc, and the organic matter contained in it is the main reason for its blackening. The main mineral in black talc is talc, its content is more than 92%, and it also contains about 5% of quartz and about 2% of organic matter. my country's black talc resources are very rich, and the proven ore spots are mainly distributed in the south-central and southwest regions of China. According to the geological characteristics of ore formation, it can be divided into three types: regional metamorphism, hydrothermal metasomatism and weathering deposition. [0003] Compared with white talc, the use of black talc is more restricted, so the price is lowe...

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Problems solved by technology

[0005] Therefore, the calcined product is no longer a talc structure after mineralogy analysis, but has become enstatite with high hardness (Mohs hardness 5.5), and has lost the talc (Mohs hardness 1) with low hardness, good greasy feeling, Good lubricity and good flow aid, thus losing the application in many fields that require the use of talc, such as plastics, medicine, food, cosmetics, coatings, paints, papermaking, waterproof materials and other industries, making it lose talc due value

In addition, in order to improve the whiteness of the existing technology, whitening agents are usually added, which not only has a mediocre effect, but also corrodes the equipment

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