Abstract: Magnesium hydroxide was synthesized through direct precipitation method with MgCl₂ as raw material and ammonia as precipitant.However,the bad filtration property of Mg(OH)₂ slurry is the one of most difficult problems in the industrial production.Wet surface modification experiment for the superfine magnesium hydroxide was carried out with sodium stearate and titanium phosphate coupling agent,so that the surface and filtration properties could be both improved.Results showed that the superfine magnesium hydroxide slurry with solid concentration of 15% was adopted as raw material,and the best dosage of surface modifier was 2.0% of magnesium hydroxide powder.In addition,the operation and production capacity were discussed by taking a BM70-800/25 plate filter press as example. 

Key words: superfine magnesium hydroxide, surface modification, filtration property