March 3, 2021
Vietnam Calcium Carbonate in the paper industry
Vietnam Calcium Carbonate in the paper industry

Vietnam Calcium carbonate is used in the paper industry mill as a filler material in the alkaline papermaking process. Nowadays Vietnam Calcium carbonate dominant over other papermaking filler materials; though at the first stage of papermaking kaolin was 1st choice. The main reason behind the preference for Vietnam calcium carbonate is the demand for brighter and bulkier paper.

There are significant benefits to the use of calcium carbonate in the al¬kaline papermaking process. But Calcium Carbonate filler is unsuitable in acid papermaking and wood-containing paper.

Usually, Vietnam Calcium Carbonate occurs in three natural forms such as limestone, chalk and marble. Naturally, it is formed between the reactions of calcium salt and carbon dioxide. This process is still going on in the Oceans.
There are two types of calcium carbonate used in paper mill – ground calcium carbonate (GCC) and precipitated calcium carbonate (PCC).

Ground calcium carbonate (GCC)
Ground calcium carbonate is manufactured by grinding limestone or marble because of its high brightness and purity. Generally, the particle shape of ground calcium carbonate is rhombohedral. This filler material is used in the alkaline wood free papermaking process. The brightness of GCC is 86-95%.

Advantages of Ground calcium carbonate (GCC)
GCC is cheaper and it has high brightness.
GCC creates a porous surface on the paper sheet due to its rhombohedral particle shape.
GCC is hydrophobic as a result it is liberated water more rapidly.
Improve printability
Lower binder demand

Disadvantages of Ground calcium carbonate (GCC)
The rough particle shape of GCC creates a problem; it is more abrasive and shortens the life of paper machine clothes.

Precipitated calcium carbonate (PCC)
Precipitated calcium carbonate in the form of CaCO3 is manufactured by chemical reactions and the process is known as the carbonation process. PCC improve the drawback of GCC, it provides better gloss and opacity properties for the paper. Because the structure of PCC is different from the structure of GCC. The crystal structure of PCC is needle-shaped, rhombohedral(cubic), scalenohedral (triangular) and prismatic. The brightness of PCC is 90-97%.

Advantages of Precipitated calcium carbonate (PCC)
Increase machine speed and productivity.
Improve water drainage
Improve machine runnability
Improve print quality
Cost-effective papermaking process
Increased opacity and brightness
PCC is less abrasive than GCC
Reduce fibre consumption compared with GCC or talc
More retention compare than other paper fillers

Disadvantages of Precipitated calcium carbonate (PCC)
PCC containing paper sheets are poorer formation than GCC containing paper sheets.

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