Rapid efficient iron-removing whitening method for low-grade raw material

Abstract

The invention discloses a rapid efficient iron-removing whitening method for a low-grade raw material, comprising the following steps: pulverizing the low-grade raw material into mineral slurry, adding an organic acid, introducing a reducing gas, conducting a reaction at 25-95 DEG C, and after completion of the reaction, conducting solid-liquid separation, washing and drying to obtain a raw material having a reduced iron content. According to the invention, the reducing gas is directly introduced to perform iron removal and whitening when acid soaking is conducted, no new impurity is introduced, the operation is fast and efficient, and the introduced reducing gas can be recycled, so the method saves energy and is friendly to environment and low in processing cost. The raw material processed by the method is directly used for ceramic production, and the product whiteness and performance indicators fully meet the requirements of industry.

Description

technical field [0001] The invention discloses a method for fast and high-efficiency iron removal and whitening of low-grade raw materials. Background technique [0002] my country is rich in mineral raw material resources, but there are not many high-grade raw materials that can be directly used in industrial production, and they are becoming increasingly scarce. Medium and low-grade raw materials often contain more harmful impurities (such as iron impurities), which seriously hinders their high-efficiency utilization. Excessive iron impurity content will not only affect the color (whiteness) of ceramic products, but also destroy the dielectric properties and chemical stability of ceramics. In the production of daily-use porcelain and building ceramics, it is usually required that the iron content of the raw material is less than 0.5wt%. Therefore, the iron removal and whitening treatment (high quality) of low-grade raw materials is of great significance. [0003] At pre...

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Problems solved by technology

For example, the patent "A method for iron removal and whitening of kaolin by sedimentation pickling" (CN105925016A) discloses a method of iron removal by sedimentation pickling that has undergone processes such as sodium hydrosulfite bleaching, flocculation sedimentation, pickling iron removal, and flash drying. This method has obvious iron removal effect, but it will introduce the impurity of bleaching powder, and the operation process is complicated, and the iron removal cycle is long; Using formaldehyde and acetaldehyde instead of hydrosulfite to reduce and remove iron, this method avoids the impurities brought by hydrosulfite, but sulfuric acid is highly corrosive, requires high equipment, and high process costs; Technology Research” (Mineral Protection and Utilization, 2003.1, 24-27), adding aluminum powder and zinc powder in the acid leaching process has a good effect of iron removal and whitening, but the added zinc powder and aluminum powder will remain in the raw materials as impurities ; The patent "Whitening method of washing iron-dyed kaolin" (CN101602898A) discloses a method of water washing, hydrosulfite reduction and high-temperature chlorination, and the patent "Preparation method of ultra-fine high-whiteness kaolin" (CN102491355A) , discloses a method of iron removal and whitening by adding ammonium chloride as a whitening agent, but they need calcination, and the calcination process will be accompanied by Cl 2 , HCl, NH 3 Toxic and harmful gases are produced, the environment is polluted, and the corrosion is strong (high equipment requirements), and the calcination process consumes a lot of energy and takes a long time

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