Industrial Aluminum Sulfate is a white orthorhombic crystal powder, but for a long time, there will be yellow case, then if it is yellow can still use it? The following is the answer to it.
First, the reasons for yellow
The ferrous iron exposed to the air and its aqueous solution are more likely to turn yellow. This is due to the exposure of green alum in the air is weathering, ferrous sulfate in the iron for the reductive, with the air contact with the air easily oxygen or other oxidizing substances oxidized to ferric sulfate. Its molecular formula changes, from the original bivalent iron change trivalent iron. The color is also changed from the original blue / green to yellow or brown. Especially in the humid and humid, the oxidation rate will accelerate, more likely to produce yellowing phenomenon. With the increase in the degree of oxidation, slowly forming a block, like a stone like a stone.
The oxidized Industrial Aluminum Sulfate used to irrigate the plant does not produce adverse effects, but its effect is far less than before the deterioration. Because the plant is absorbed by the ferrous ions, and at this time most of the ferrous ions are oxidized into trivalent iron ions, not easily absorbed by plants. But if it is used for sewage treatment decolorization or coagulation purposes, then the ferric and ferric iron its coagulation effect is not much difference, restore the decolorization effect of ferric iron does not have.
Second, to prevent the yellow method
Improve the packaging seal, reduce its contact with the air, and place a dry place. The liquid product is recommended with the current use, or in the solution into the nails, iron, iron powder. Also do not put alkaline chemicals with alkaline fertilizers, chemical oxidants and Industrial Aluminum Sulfate placed together or coagulation preparation, it is weak acid, will react with alkaline chemicals lead to its loss of effect.