抄録
For examining to what extent quartz in bauxite reacts with alkali solusion during the extraction of alumina, experiments have been made on the reaction of guartz in bauxite with caustic soda solusion and alumina pregnant liquor. The findings are as follows:
1. The guantily of quartz dissolved in caustic soda solusion increases in proportion to the surface area of quartz. It increases also with the increase in the temperature and concentration of the sdusion. The dissolving velocity becomes about double per 10°C of temperatue-rising and about 1.3 times as alkali concentration is doubled.
2. The reacting velocity of quartz in alumina pregnant liguor is slower than that in caustic soda solution. the velocity in alumina pregnant liguor with 1.7 of Na2O/Al2O3mol, ratio is 1/10 of that in caustic soda solution.
3. It is presumed that the reacting quantity of quartz during the extraction of alumina from bauxite by low-pressure-Bayer-process using tri-hydrate bauxite is less than 2% of the contents of quartz in bauxite.
