Ammonium Sulfate

Physicochemical Characteristics

The genuine specific gravity of solid aluminum sulfate is about 1.62, but its temporary specific gravity is 0.6~0.7. The graph below shows the relationship among the specific gravity, the temperature and the concentration (%) of liquid aluminum sulfate. The chart will determine the sulfate's concentration (%).

Refer to the chart for the relationship between the concentration and the mucosity of aluminum sulfate.

Refer to the chart for the relationship between the valid ingredient of the neutral salt/acid solution and the pH (at 20°C) of the liquid aluminum sulfate sample: A - when it is neutral salt, and B - when its basicity is 0.025%.

The crystallization temperature of liquid aluminum sulfate is lowest (about -14°C) when its concentration is less than 8%. Its crystallization temperature rises dramatically, however, when its concentration is greater than 8.2%, and it finally closes pipes/devices in concentrations greater than 8.6%. The crystallization temperature of liquid aluminum sulfate rises gradually even in less-than-8.3% concentrations. Therefore, the concentration of the product in the market is either 7.0% or 8.0%.

The composition of aluminum sulfate can be expressed, and solid aluminum sulfate is expressed, as AL2(SO4)3 nH2O due to the crystallization of water molecules. In Korea, products with 14-16 molecules are generally manufactured. These are colorless crystals that are soluble in water but insoluble in alcohol. The hydrosoluble liquid extracts the precipitation of hydroxy aluminum, which is acidic. If the solution is boiled for a long period of time, basic aluminum sulfate forms.