A preparation method of a flocculant for effectively settling and separating high-silicon and high-iron type Bayer red mud

Abstract

The invention relates to a method for preparing a flocculant for efficient settling separation of high-silicon and high-iron type red mud generated through a Bayer process. In the preparation of the flocculant, polyacrylamide with high molecular weight is used as a raw material, and a one-pot synthetic process with acidification of hydroxamic acid and hydrolysis conducted at the same time is adopted to prepare the flocculant with the contents of hydroxamic acid and carboxyl up to 39.8% and 47.6% respectively, and the synthesis steps are simple. The synthesized flocculant can be used for effectively settling red mud generated in current production of low-grade high-silicon and high-iron diasporic bauxite through the Bayer process in China, the difficult problem that various flocculants are required to be added for settling separation of red mud in conventional aluminium oxide manufacture is overcome, cost is reduced, and industrial requirements are met.

Description

technical field [0001] The invention relates to a preparation method of a flocculant capable of effectively settling and separating high-silicon and high-iron red mud of Bayer process. Background technique [0002] With the depletion of bauxite resources in my country, the grade of refractory diaspore bauxite used in alumina plants is getting lower and lower, and the proportion of silicon-containing minerals and iron-containing minerals has increased, and a large number of high-grade bauxites have appeared. Silicon-high-iron-diaspore type bauxite leads to the production of high-silicon-high-iron type Bayer process red mud. However, the existing commercial flocculants for settling the above-mentioned red mud generally only contain carboxyl or hydroxamic acid groups, or although they contain the above groups at the same time, the carboxyl and hydroxamic acid groups are too low to effectively settle and separate high-silicon High-speed iron type Bayer process red mud. [0003]...

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Problems solved by technology

In 2009, Wang Shanshan et al. (Wang Shanshan. Development of water-soluble hydroxamic acid polymer flocculant [J]. Chemical Abstracts, 2009, 03:29-30) used polyacrylamide as raw material and hydroxylamine hydrochloride as modification in the aqueous solution synthesis system. Synthetic hydroxamic acid flocculant, but the content of hydroxamic acid group in this flocculant is unknown, and this flocculant can only be used to treat oily sewage in oil field sewage station

However, in the actual application process of this flocculant, it is still difficult to meet the high-efficiency flocculation requirements for high-silicon and high-iron Bayer red mud; Cationic groups exist in the form of quaternary ammonium bases under strong alkaline conditions, and quaternary ammonium bases are easy to decompose at 95-100 ° C and lose flocculation (Zhang Kunyu, Hu Huiping, et al. Thermal decomposition behavior of polyacrylamidomethyltrimethylammonium chloride in redmud separation process [J]. J. Cent. South Univ .Technol.2008(15):808~813)

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