Simultaneous preparation of binary and ternary high-performance composite aerogels from iron tailings

Abstract

The invention discloses a method for preparing binary and ternary high-performance composite aerogels by using iron tailings. The method comprises the following steps: mixing the iron tailings with sodium hydroxide for alkali fusion activation, cooling and washing with deionized water for solidification Liquid separation, after the washing liquid is allowed to stand for stratification, the supernatant liquid is separated from the lower mixed liquid, an acidic catalyst is added under alkaline conditions, and the wet gel is obtained by standing and aging, and the wet gel is subjected to solvent replacement and then dried under normal pressure to obtain Binary and ternary composite aerogels. The invention uses iron tailings as raw materials, has low price, wide sources, mild preparation conditions, simple process, low equipment requirements, is easy to realize industrialized preparation, and can simultaneously obtain binary and magnetic ternary composite silicon-based gas condensation; The tap density of the aerogel is less than 0.20g / cm 3 , the specific surface area of ​​binary aerogel and ternary aerogel can reach 986m, respectively 2 / g and 612m 2 / g, the adsorption capacity of methylene blue exceeds 300mg / g.

Description

technical field [0001] The invention relates to a method for simultaneously preparing binary and ternary composite aerogels by using iron tailings as raw materials, and belongs to the field of aerogel preparation. Background technique [0002] SiO 2 Aerogel is a nanomaterial with a three-dimensional network porous structure composed of nano-scale silica particles. It has high specific surface area, extremely low density, and low room temperature thermal conductivity. In thermal insulation, adsorption, CO 2 It has good application prospects in many fields such as isolation, catalyst carrier, aerospace and so on. The main preparation process of silica aerogel usually includes two typical steps of sol-gel and drying, which are used to form and maximize the three-dimensional structure of the gel, so as to finally obtain aerogel products. Ethyl orthosilicate (TEOS) is a silicon source to obtain silica aerogel through supercritical drying, but there are still many challenges in...

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Problems solved by technology

The main preparation process of silica airgel usually includes two typical steps of sol-gel and drying, which are respectively used to form and maintain the three-dimensional structure of the gel to the maximum extent, so as to finally obtain the airgel product. The currently recognized mature process is usually as follows: Tetraethyl silicate (TEOS) is a silicon source that undergoes supercritical drying to obtain silica airgel, but there are still many challenges in technology and application. For example, the price of TEOS silicon source is relatively high, and supercritical drying equipment requires strict requirements. Therefore, in order to overcome the above shortcomings, it is of great practical significance to find cheaper silicon sources and simpler drying methods

At present, there are few relevant reports on preparing aerogels from silica in tailings. Publication No. CN108658130A discloses a method for simultaneously preparing iron oxide and silica aerogels from iron tailings. The method includes pickling Iron extraction and alkali melting extraction of silicon are used to obtain iron source and silicon source respectively, but the problem of combining the two to prepare composite materials is not solved; Publication No. CN109133072A discloses an ultra-fast preparation of hydrophobic silica using iron tailings as raw material The method for airgel, publication number CN109012517A discloses a method for preparing composite silicon-based airgel with iron tailings as raw material, although the above method obtains alumina and silicon dioxide to a certain extent However, due to the low initial alkali fusion treatment temperature, the iron oxide is still retained in the alkali slag, and the iron oxide in the tailings cannot be extracted to prepare the iron oxide / silica airgel composite material

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