Main ingredients

Heavy calcium carbonate is mainly a powder material obtained by mechanical grinding and processing of natural minerals such as calcite, marble, limestone, chalk, and white marble as raw materials;

Light calcium carbonate is mainly a powder material obtained from limestone as raw material through processes such as calcination, digestion, carbonization, dehydration, drying, and classification.

Product bulk density

The difference in product bulk density is the most obvious difference between heavy calcium carbonate and light calcium carbonate.

The bulk density of heavy calcium carbonate products is relatively large, generally 0.8~1.3g/cm3;

The bulk density of light calcium carbonate products is small, generally 0.5-0.7g/cm3, and the bulk density of some nano-calcium carbonate products can even reach about 0.28g/cm3.

Oil absorption value

Heavy calcium carbonate has a low oil absorption value due to its large particles, smooth surface, and small specific surface area, generally around 40-60mL/100g;

Light calcium carbonate has fine particles, rough surface, and large specific surface area, so its oil absorption value is high, generally around 60-90mL/100g.

BaiDu

Heavy calcium carbonate has relatively more impurities, so the product whiteness is generally 89% to 93%, and very few products can reach 95%;

Light calcium carbonate products have high purity, so the whiteness is generally 92% to 95%, and some products can reach 96% to 97%.

Moisture content

The moisture content of heavy calcium carbonate products is generally 0.2% to 0.3%. The moisture content is relatively low and relatively stable. The moisture content of some high-end products can even reach about 0.1%;

Ordinary light calcium carbonate products have a moisture content of 0.3% to 0.8%, which sometimes fluctuates and is unstable.

Powder characteristics

The characteristics of heavy calcium carbonate powder are: irregular particle shape, and the particles have certain edges and corners, and the surface is rough; the particle size difference is large, the particle size distribution is wide, and the particle size is large. Crushing and refining will not change the crystal form of heavy calcium carbonate. Generally, calcite heavy calcium carbonate is in the hexagonal crystal form, and marble heavy calcium carbonate is in the cubic crystal form, which is mainly related to the place of origin.

The characteristics of light calcium carbonate powder are: the particles have regular shape and can be regarded as monodisperse powder; the particle size distribution is narrow. According to the shape of the crystal grains, light calcium carbonate can be divided into spindle-shaped, cubic, needle-shaped, chain-shaped, spherical, flaky and rhombus-shaped.

particle size

Spindle-shaped calcium carbonate is the most common crystal form among light calcium carbonates, with an average long-axis particle size of 5-12 μm and an average short-axis particle size of 1-3 μm;

The average particle size of needle-shaped calcium carbonate is 0.01-0.1μm, and the average aspect ratio is 5-100;

The average particle size of chain calcium carbonate is 0.01-0.1μm, and the average aspect ratio is 10-50;

The average particle size of spherical calcium carbonate is 0.03-0.05μm;

The average particle size of cubic calcium carbonate is 0.02-0.1μm;

The average particle size of flake calcium carbonate is 1-3 μm.

Due to the incomplete reaction of calcium oxide, light calcium carbonate has a residual lime taste. It will have a choking taste when filling biscuits, while heavy calcium carbonate does not.

The particle size of heavy calcium carbonate products ranges from 0.5 to 45 μm. According to its original average particle size (d), it is divided into: coarsely ground calcium carbonate (>3μm), finely ground calcium carbonate (1-3μm), and ultrafine calcium carbonate. (0.5-1μm);

Light calcium carbonate can be divided into: micron calcium carbonate (>5μm), micronized calcium carbonate (1-5μm), fine calcium carbonate (0.1-1μm), ultrafine calcium carbonate (0.02-1μm) according to its original average particle size (d). 0.1μm), ultrafine calcium carbonate (<0.02μm).

Sedimentation volume

The sedimentation volume is the volume of unit mass of calcium carbonate after shaking in 100 mL of water and letting it stand for 3 hours.

The larger the sedimentation volume, the smaller the product particle size, the lighter the density, and the higher the product grade.

The sedimentation volume of heavy calcium carbonate is 1.1~1.4mL/g;

The sedimentation volume of light calcium carbonate is 2.4-2.8mL/g, and the sedimentation volume of nano-light calcium carbonate is 3.0-4.0mL/g.

The specific surface area of ordinary heavy calcium carbonate is generally about 1m2/g, and the specific surface area of heavy fine calcium carbonate is 1.45~2.1m2/g;

The specific surface area of ordinary light calcium carbonate is generally about 5m2/g, and the specific surface area of light and fine calcium carbonate is 27~87m2/g.

fluidity

From the perspective of fluidity, the microstructure of light calcium carbonate is a spindle shape, and its own oil absorption value is relatively large. Components that promote flow in the formula, such as lubricants, plasticizers, coupling agents, dispersants, etc. Absorption, so its fluidity is not as good as heavy calcium carbonate. Generally, adding more than 25 parts will seriously affect the fluidity;

The granular form of heavy calcium carbonate can promote fluidity, and the amount added is not limited. If more than 25 parts of calcium carbonate are added to the PVC pipe formula, it is best to use heavy calcium carbonate from the perspective of fluidity.

Processing technology

The processing of heavy calcium carbonate is mainly achieved through mechanical crushing and grinding;

The production of light calcium carbonate is made through chemical reaction precipitation. The latter process is much more complicated than the former, and the requirements are correspondingly stricter. Therefore, heavy calcium carbonate of the same particle size is 30 times cheaper than light calcium carbonate. About %, if the performance allows, you can choose heavy calcium carbonate, which is more economical and cheaper.

Tensile Strength

Heavy calcium carbonate has better tensile strength, and the processing fluidity of heavy calcium plastic is better, and the performance of heavy calcium filled plastic with smaller particle size is also better;

Light calcium carbonate has better impact strength and rigidity. Generally, the surface of plastic made of light calcium carbonate is smoother and the density is lower.

Hue

Hue is the main hue of a color, while chromatic light is the afterglow of a color. Powders with different crystal forms have different hues. Calcium carbonate has three different crystal forms, so it also has different hues.

For heavy calcium carbonate, the background color of calcium carbonate from different origins is different, and it will not change when broken and refined. For example, the background color of Sichuan calcium carbonate is blue, the background color of Guangxi calcium carbonate is red, and the background color of Jiangxi calcium carbonate is different. cyan, etc.;

As for light calcium carbonate, because it is artificially made by chemical synthesis, the type of crystal form it produces can be controlled during the synthesis process, and therefore the type of its color light can be controlled. In the specific color matching, the color of calcium carbonate should be consistent with the color of the main colorant.

pH value

The pH value of heavy calcium carbonate is 8-9;

The pH value of light calcium carbonate is 9-10.

preparation cost

Powder preparation cost: Conventional costs are equivalent and at the same competitive level, but if additional environmental control costs and resource waste rates are added, the expansion cost of light calcium carbonate is higher than that of heavy calcium carbonate;

environmental balance

Environmental balance: The production of heavy calcium carbonate emits no "three wastes" except noise, and the environment is easy to coordinate and control; the production of light calcium carbonate emits "three wastes", especially combustion exhaust gas, and the overall environmental balance is low;

Resource utilization

Resource utilization rate: Heavy calcium carbonate is easy to comprehensively utilize mineral resources, while light calcium carbonate is difficult to control the reasonable utilization rate of mineral resources due to its chemical processing capabilities.

Application scope

Heavy calcium carbonate products: Mainly used in papermaking, rubber and plastics industries, the filling volume is generally large, mainly used as volume filler to reduce the manufacturing cost of applied products;

Light calcium carbonate products: have a relatively wide range of applications. The main application areas are plastics, rubber, coatings, adhesives, cigarette papers, inks, etc., mainly for volume filling, while nano calcium carbonate products are often used as Functional fillers such as modified or reinforced are used, and the filling amount is generally small.