Uses
The compound is used heavily in the paper industry. In its acidic solution form, which contains a slight excess of H2SO4, it is used for pH control of pulp slurries, treatment of process waters, setting of dyes and also for precipitating dissolved resin for setting the size on the fibers. In slight basic form (containing a slight excess of Al2O3), it is used for treatment of drinking and waste waters (e.g., for reducing phosphorus content). Other major applications include dyeing, tanning, catalysts, modification of concrete, and in the manufacture of various chemicals and pharmaceutical products.
Preparation
Prepared from bauxite, kaolin or aluminum compounds on reaction with H2SO4. The insoluble silicic acid is filtered out; the hydrate salt forms on crystallization.
Chemical Properties
white crystalline powder and chunks
Physical properties
White crystal; sweet taste; density 1.62 g/cm
3: decomposes at 86.5°C; soluble in water.
Uses
Aluminium sulfate octadecahydrate is a preservative, the inclusive term for several inum-type compounds such as inum sulfate and inum potassium sulfate. It is used with edta to prevent discoloration of potatoes and to maintain the firmness of shrimp packs. It is also used in pickles and pickle relish.
Definition
ChEBI: A hydrate resulting from the the formal combination of anhydrous aluminium sulfate with approximately 18 mol eq. of water. The commercial product usually contains 5-10% less water than theory. It is one of the commonest hydrates of aluminium sulfate.
