Preparation method of fly ash-based ceramic membrane support

A preparation method of a fly ash-based ceramic membrane support, comprising the following steps:

• 1) subjecting fly ash to alkali washing and acid washing to obtain pretreated fly ash;
• wherein the alkali washing is conducted using an alkali washing solution selected from the group consisting of 2 wt % to 4 wt % of a sodium hydroxide solution and 15 wt % to 25 wt % of a sodium carbonate solution, and a solid-to-liquid ratio of the alkali washing solution is in a range of 1 kg:
• 1.5 L to 1 kg:
• 3 L;
• and the acid washing is conducted using an acid washing solution selected from the group consisting of 1 wt % to 3 wt % of a citric acid solution, 3 wt % to 7 wt % of a hydrochloric acid solution, 1 wt % to 5 wt % of a sulfuric acid solution, and 0.5 wt % to 3 wt % of a nitric acid solution, and a solid-to-liquid ratio of the acid washing solution is in a range of 1 kg:
• 0.5 L to 1 kg:
• 2.5 L;
• 2) blending a raw material, and then conducting aging and extrusion molding to obtain a green body;
• the raw material comprises the following components in parts by mass:
• 80 parts to 95 parts of the pretreated fly ash, 6 parts to 9 parts of a plastic clay, 5 parts to 8 parts of a pore-forming agent, 2 parts to 4 parts of a binder, 20 parts to 28 parts of water, 1 part to 2 parts of a lubricant, 2 parts to 4 parts of a water-retaining agent, 0.5 parts to 1 part of a water-reducing agent, and 0.1 parts to 0.3 parts of a release agent;
• and
• 3) spraying a surface water-retaining agent on a surface of the green body to allow static curing in a constant-temperature and constant-humidity environment, and then conducting drying and sintering after the curing is completed;
• wherein the surface water-retaining agent is prepared from glycerol, tung oil, a diol, and polyethylene glycol at a mass ratio of (1-2.5):(2-4):(0.3-0.7):(0.5-1).