At present, the production methods of heavy calcium carbonate mainly include dry method and wet method. The dry method generally produces heavy calcium with less than 2500 mesh. If the heavy calcium with more than 2500 mesh is produced, wet grinding is mainly used, and dry grinding is the first step of wet grinding. Wet grinding heavy calcium has the characteristics of good processing fluidity, high surface brightness and excellent mechanical properties, and is mainly used in plastic products; With the increase of fineness, the contrast ratio, washability and whiteness of latex paint applied to interior walls gradually increase. Therefore, more and more heavy calcium manufacturers have begun to develop the production of wet grinding heavy calcium from the dry process heavy calcium processing production line. HCMilling(Guilin Hongcheng), as the manufacturer of heavy calcium grinding mill machine, will introduce the production and application of wet grinding heavy calcium.

1、 Production of wet grinding heavy calcium carbonate: first, the suspension of dry grinding heavy calcium powder is put into the heavy calcium grinding mill for further crushing, and then the ultra-fine heavy calcium carbonate is prepared after dehydration and drying. The production process of wet grinding heavy calcium is as follows:

(1) Raw ore → jaw breaking → calcium carbonate Raymond mill → wet mixing mill or stripping machine (intermittent, multi-stage or circulation) → wet classifier → screening → drying → activation → bagging (coated grade heavy calcium carbonate). Wet ultrafine classification is added to the process flow, which can timely separate qualified products and improve efficiency. Wet ultrafine classification equipment mainly includes small diameter cyclone, horizontal spiral classifier and disc classifier. The slurry after classification is relatively thin, and sometimes a sedimentation tank is required. The process has good economic indicators, but classification is difficult to operate. At present, there is no very effective wet ultrafine classification equipment.

(2) Raw ore → jaw breaking → calcium carbonate Raymond mill → wet stirring mill → screening → drying → activation → bagging (filler grade heavy calcium).

(3) Raw ore → jaw breaking → calcium carbonate Raymond mill → wet stirring mill or stripping machine (intermittent, multi-stage or circulation) → screening (paper coating grade heavy calcium slurry).

2、 Advantages of wet grinding heavy calcium: compared with dry grinding heavy calcium, wet grinding heavy calcium has some obvious advantages. Mainly reflected in the following aspects:

(1) Particle size: the superfine heavy calcium produced by wet grinding has fine particle size, mainly producing products with more than 3000 meshes,<2 μ The content of m can generally reach 90%, while the grain size of dry products is relatively coarse, mainly producing products below 2500 mesh.

(2) Particle size distribution: the particle size distribution of heavy calcium produced by wet process is narrow, with single or double peak distribution; However, the particle size distribution of heavy calcium produced by dry method is relatively wide, and it is in the form of double or multiple peaks.

(3) Granular: Due to the different grinding environment and stress mode of particles during grinding, the particles of wet grinding heavy calcium products are generally spherical or quasi-spherical, while the dry method products are mostly amorphous with obvious edges and corners.

(4) Moisture: The wet superfine heavy calcium has gone through the drying process in the production process, and the moisture is generally controlled below 0.3%, but the moisture of the heavy calcium produced by the dry method cannot be controlled, generally more than 1%. Therefore, the dispersion and fluidity of the wet superfine heavy calcium during the modification process are obviously better than those produced by the dry method.

3、 Apply the heavy calcium grinding mill to wet grinding of heavy calcium:

(1) Emulsion paint: When calcium carbonate is used as filler in latex paint, it plays a filling role and has a certain dry covering performance, which not only reduces the cost of latex paint, but also acts as a skeleton, and improves the film thickness, hardness, water resistance and scrub resistance. Therefore, the application of heavy calcium in the building coating industry is more and more extensive.

(2) Permeable membrane: The dispersity and particle size (size and distribution) of calcium carbonate powder determine the fluidity of the powder itself, and also directly affect the production speed and process stability of the permeable membrane, which has a decisive role in the tensile porosity, pore structure, permeability and mechanical properties of the permeable membrane. The use of heavy calcium produced by wet grinding as “porogen” has lower oil absorption value, better dispersion and fluidity, and can also significantly reduce the amount of carrier resin, plasticizer, lubricant and other additives.

(3) Color masterbatch: Color masterbatch coloring is the most commonly used method in plastic coloring at present, which is usually composed of carrier resin, pigment and additives. A large number of studies have shown that using calcium carbonate, wollastonite or barium sulfate to replace some pigments to prepare color masterbatch can improve the dispersion of pigments and reduce production costs without reducing the color performance of color masterbatch. Some studies have shown that the color masterbatch prepared by wet grinding calcium bicarbonate instead of titanium dioxide, when the substitution amount is 20%, the coloring performance remains unchanged, and the performance is very similar to that of pure pigment, with small color difference.

As the manufacturer of heavy calcium grinding mill machine, the HCQ, HC series large heavy calcium Raymond mill, HLM heavy calcium coarse powder vertical grinding mill and other heavy calcium grinding mill equipment produced by HCMilling(Guilin Hongcheng) have been widely used and won a good reputation in the front-end dry production of wet grinding heavy calcium. If you have a production demand for wet grinding of heavy calcium and need front-end dry grinding mill equipment, please contact HCM for details of the equipment.