Ammonium → Tetraaluminum;trisilicate

Participants

Reaction Steps

Sodium silicate and aluminum sulfate, which are used as raw materials, are continuously mixed together while stirring so that the molar ratio of Si to Al equals 1:1. At the same time, sodium hydroxide is added to neutralize the mixture so that the reaction pH is in the range of 10 to 12, whereby a silica alumina gel is prepared. Then, using an aqueous ammonium nitrate solution in an amount such that the equivalent ratio of the aqueous ammonium nitrate solution to sodium in the gel equals 2:1, sodium is ion-exchanged for ammonium at room temperature. Then, exchanged ammonium is removed through baking at 600° C. for 2 hours. Furthermore, the residue is dry-ground to prepare a raw material powder. The raw material powder is placed in an autoclave to make the powder undergo a hydrothermal reaction at 200° C. for 1 day, and at 250° C. for 3 days so that its slurry concentration is 10 wt %. After cooling, the reaction solution is filtered under a reduced pressure by using a Buchner funnel (Nutsche funnel) to separate a mother liquor, and the residue is then dried and ground to obtain hydrous aluminum silicate particles (P) having an average particle size of 200 nm. (Q) Preparation of surface-untreated calcium carbonate particles

Provenance & Evidence