Yuan Lei's Little Knowledge | (II) of Difference between Light Calcium Carbonate and Heavy Calcium Carbonate

Release time:

2024-01-29 09:34

According to the different production methods of calcium carbonate, calcium carbonate can be divided into heavy calcium carbonate, light calcium carbonate, colloidal calcium carbonate and crystalline calcium carbonate. Before, I have already known some differences between light calcium and heavy calcium. Let Xiaobian continue to show you the other differences between the two.



● Different particle shapes ●

With a high-power microscope, the particles of ordinary light calcium are more regular and are usually spindle-shaped when fully dispersed. For light calcium carbonate, the particle shape of the synthetic product can be artificially controlled, and the control agent can be added during the carbonization process to achieve control. At present, the developed control agents include inorganic acids, inorganic bases, organic acids (amino acids), alcohols, sugars, proteins and biopolymers with special structures. For example, the double hydrophilic block polymer PEG-b-PMAA can be made into diamond, peanut, long rod, spherical and dumbbell-shaped carbonic acid under different concentrations and different pH values. For example, the dendrimer polyaspartic acid can be made into spiral-shaped carbonic acid, as another example, spherical calcium carbonate can be obtained by adding anionic dextran.

Heavy calcium products due to the use of mechanical crushing and classification, particle morphology is generally cube, multi-prism, cuboid and other irregular forms. For different heavy calcium processing methods, the microscopic shape of calcium carbonate is different, for example, the calcium carbonate processed by rein grinding is spindle-shaped, and the calcium carbonate processed by air flow grinding is particle-shaped.

● Different oil absorption values ●

The oil absorption value of light calcium carbonate is 60-90 ml/100mg, which is much larger than 40-60 ml/100mg of heavy calcium carbonate. Therefore, there is a big difference between liquid absorption and resin absorption. If the formula contains liquid additives, heavy carbonic acid with small oil absorption and inorganic powder with large oil absorption value should be selected, which will lead to an increase in the amount of coupling agent to be treated. If you choose light carbonic acid in the PVC formula, you will consume more liquid additives and PVC trees. Therefore, considering the oil absorption value, you should choose heavy calcium carbonate with low oil absorption value as much as possible.



● Liquidity is different ●

From the perspective of fluidity, the microstructure of light calcium carbonate is spindle-shaped, and its own oil absorption value is relatively large, which can absorb the components that promote flow in the formula, such as lubricants, plasticizers, coupling agents, dispersants, etc., so its fluidity is not as good as heavy calcium carbonate. Generally, the fluidity will be seriously affected if the addition amount exceeds 25 parts, while heavy calcium carbonate can promote fluidity if it is granular, and the addition amount is not limited, in the PVC pipe formula, if more than 25 copies of calcium carbonate are added, it is best to choose heavy calcium carbonate from the perspective of fluidity.

● Different pH values

The PH value of light calcium carbonate is 9-10, while the PH value of heavy calcium carbonate is 8-9, that is to say, the alkalinity of light calcium carbonate is stronger than that of heavy calcium carbonate, and it is easier to absorb acidic decomposition gas during the combustion process of calcium carbonate composite products. Therefore, the reason why calcium carbonate composite products incinerate low-toxic gas is that calcium carbonate itself is alkaline, which can absorb HCI, H2S and other acidic gases produced by combustion, and eliminate the hidden danger of dioxins produced by acid energy substances in case of chlorine elements.

● Different modification functions ●

There are subtle differences between the modification effects of heavy and light calcium carbonate. Heavy calcium carbonate has better tensile strength, while light calcium carbonate has better impact strength and rigidity. Generally, the plastic surface with light calcium is smoother and the density is lower. The processing fluidity of heavy calcium plastic is better, and the performance of heavy calcium filled plastic with smaller particle size is also better.

Calcium carbonate, different, can, light, flowability, particle, shape, absorption, if

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