A method for preparing aluminum-iron flocculant from red mud

Abstract

A method for preparing an aluminum-iron flocculant from red mud. First, the red mud is washed with water to obtain a washing solution and washing residue, and then the washing residue is mixed with citric acid, tannic acid, and malic acid in a mass ratio of 1:3. ‑7, the reaction temperature is 80 o C‑100 o C. Mix and stir for 30-90min under the condition that the stirring intensity is 250-400r / min. After the stirring is completed, the solid-liquid separation is obtained to obtain titanium-rich material and pickling solution. Use water washing solution to adjust the pH value of the pickling solution to 7-9, and then Add the mixed polymer agent of nitrilotriacetic acid and phytic acid according to liquid-solid mass ratio 5-10:1 and stir and dissolve, after stirring, at 50 o C‑80 o Under the condition of C, heat preservation and aging for 5-10h, then standing and aging at room temperature for 24-48h, then discharge the aging upper layer liquid to obtain milky polymerized aluminum-iron flocculant, and finally in 100-110 o Dry under C conditions for 8-16 hours to obtain aluminum-iron flocculant products with water-soluble impurities less than 0.2%.

Description

technical field [0001] The invention belongs to the technical field of comprehensive utilization of red mud, in particular to a method for preparing an aluminum-iron flocculant from red mud. Background technique [0002] Red mud is the waste residue produced during the production of alumina. It is red because it contains a large amount of iron oxide, so it is called red mud. At present, the main disposal method of red mud in our country is to stockpile and build dams, which not only takes up a lot of land, but also consumes a lot of maintenance costs. It is worth noting that the alkalinity of red mud seriously damages the ecological environment, so the comprehensive utilization of red mud is particularly important in today's scarce resources (Liu Shuren, Xie Gang, Li Rongxing, etc. Comprehensive utilization [J]. Mining and Metallurgy, 2015, 24(3):72-75.). Red mud is rich in a variety of valuable metals such as aluminum, iron, titanium, scandium, yttrium, vanadium, etc., an...

AI Technical Summary

Problems solved by technology

This method has complicated raw materials, complex process, and high cost of some raw materials

There are also studies using iron ore, coal gangue, fly ash, slag, etc. as raw materials, roasting, leaching with a large amount of hydrochloric acid, and using NaOH as a pH regulator. The process is more complicated and the operation is more cumbersome.

Some use a single slag as raw material, and add a small amount of calcium aluminate after acid leaching to adjust the ratio of aluminum to iron and the basicity of the leaching solution. , et al. Exploration of process conditions for preparing polyaluminum chloride from kaolin tailings in Suzhou[J]. Journal of Safety and Environment, 2013, 13(5); Zhu Xiuzhen, Sun Jianzhi. Preparation of polyaluminum chloride with red mud and fly ash Iron flocculant and SiO2[J]. Chemical Environmental Protection, 2012, 32(5):444-447; Lu Fanghai. Experimental research on the production of polyaluminum ferric chloride from acid leached Bayer process red mud and the treatment of industrial wastewater[J]. Hydrometallurgy, 2015, 34(1); Liu Xi, Li Ye, Zhao Jianbo, et al. Phosphorus removal performance of fly ash-red mud composite flocculant PAFC[J]. Metal Mine, 2014, 43(7):168 -171; Yan L, Wang Y, Li J, et al.Preparation of polymeric aluminum ferric chloride (PAFC) coagulant from flyash for the treatment of coal-washing wastewater[J]. Desalination & WaterTreatment, 2016, 112(3): 1-15.), however, these aluminum-iron flocculants have low mechanical strength and high impurity content. During the process of wastewater treatment, the aluminum-iron flocculants are easily broken, which affects the flocculation effect

[0004] In summary, the use of red mud to prepare aluminum-iron flocculant is a new method to recover aluminum and iron in red mud. The utilization value of aluminum and iron is high, but there is a large acid consumption and no selectivity in the leaching process, and the leaching residue is acidic. Strong and polluting, consume a large amount of external aluminum salt or iron salt to adjust the aluminum-iron molar ratio in the aluminum-iron flocculant, high sodium hydroxide consumption in the process of adjusting the pH value, low mechanical strength of the flocculation product and high impurity content, etc.

Images