<p>New route for preparation of mesoporous silica from environmentally harmful partially dealuminated kaolin (PDK) was investigated. PDK is a residue of aluminum sulfate manufacturing process with limited recycling options due to harmful contaminants. In this work, a relatively low temperature highly alkaline reaction process was proceeded to prepare sodium silicate as an alternative of the usual high temperature dissolution of white quartz sand with sodium hydroxide in a reactor. In addition, the dissolution process steps were tested to achieve the essential principles of the hydrolysis of silica from dealuminated kaolin, which is not reported in the available publications. The chemical and mineralogical composition of the PDK was studied before and after treatment to understand the formation of alkaline aluminum silicate hydrates such as zeolites and geopolymers as a by-product. These byproducts hinder the dissolution of the silica because they consume part of the soluble silicate, and form precipitate which coats the PDK particles which prevents the dissolution of silica. The reaction was performed at a temperature of 75 ˚C for 2&#xa0;h. The extraction efficiency was 90.6% of the silica. The percentage of the recovered silica precipitate exceeded 98% at a neutral solution. The extracted silica was used for preparation of sodium silicate that was used for preparation of pure meso-porous silica (98.52%) of high BET (865 m²g), and a pore size diameter below 5&#xa0;nm.</p>