How To Improve The Whiteness Of Calcium Carbonate


Whiteness is an important indicator of calcium carbonate.In terms of whiteness alone, calcium carbonate with higher whiteness is favored by users. Therefore, how to improve the whiteness of calcium carbonate is also a very key production technology for manufacturers.

Influence factors of calcium carbonate whiteness

1. calcination,

Some manufacturers do not pay attention to the ore washing, a lot of dirt as the ore into the kiln calcine, many harmful impurities such as silica, alumina, iron oxide calcination combined with calcium oxide formation of low melting point when something "nodules" accident in the shaft kiln, tumor of adhesion on the surface of calcium oxide, reduces the product whiteness.

2. digestive

Different digestion equipment has different influence on whiteness, the influence of digestive trough is the least, the influence of paddle digestion is the second, the influence of drum digestion machine is the most.

3. refined

The refining process is one of the important factors affecting the whiteness of the slurry.Refining is to go out of the yellow and black impurities, in addition to the more thoroughly, the higher the whiteness.

Method of increasing calcium carbonate whiteness

(1) To strengthen management, improve equipment level.Heavy calcium carbonate production equipment you get what you pay for, and timely overhaul and maintenance of equipment is also important.

(2) the selection of raw ore should be carefully selected.Can be analyzed whether iron in the ore exceeds the standard, the general requirements of Fe2O3≤0.1%, more than 0.2%, the product will be yellow or even red resulting in whiteness decline, then need to be treated by chemical agents in addition to iron, such as iron pollution caused by equipment, can also be treated, if not iron exceeds the standard can not be treated with this method, otherwise it will reduce whiteness.

(3) to fully analyze the chemical composition of calcite and calcium carbonate products, if other impurities in the ore exceed the standard, it will also cause the whiteness is not high. At this time, it is necessary to increase the whiteness as much as possible through multi-level slag removal. Generally, the improvement is limited, and it is best to change ore.Bleaching techniques should be used to improve the whiteness of calcium carbonate products if they contain high levels of color minerals.

(4) According to the pigment ions contained in limestone and calcium carbonate products, reduction bleaching or oxidation bleaching or both bleaching methods shall be adopted respectively.Heavy calcium carbonate bleaching chemicals are generally put into the grinding process, grinding side bleaching;Light calcium carbonate bleaching can be divided into three forms: digestion bleaching, carbonization bleaching and bleaching in mature slurry.

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