Calcite Grinding Mill and Production Line Process

Calcite grinding mill is equipment used to grind calcite into powder. The main types include Raymond mill, vertical roller mill and ultra-fine grinding mill. Before feeding raw materials into the mill, impurity removal and iron removal must be completed. A washing process can be added if necessary to maximize the whiteness of calcite powder. If higher whiteness and purity of finished powder are required, flotation can be adopted after grinding for deep purification.

What is Calcite?

Calcite is a trigonal mineral mainly composed of calcium carbonate (CaCO₃). It is a widely distributed carbonate mineral in the earth’s crust and the core component of limestone and marble. It has a Mohs hardness of 3 and density of 2.6~2.9 g/cm³. It will bubble violently when encountering cold dilute hydrochloric acid (releasing CO₂). Normally colorless or milky white, it contains trace impurities such as magnesium, iron, manganese and zinc. The ground calcite powder is commonly used as functional filler in papermaking, plastics, coatings, rubber and other industries.

Notes for Calcite Grinding Production Line

Raw Material Treatment: Although calcite is easy to grind, quartz (Mohs hardness above 7) is often mixed in raw ore. Even a small piece of quartz entering the mill will greatly accelerate wear of grinding parts such as roller and ring. Impurities can be removed by crushing with crusher and screening with vibrating screen.

Whiteness Control: The whiteness of calcite powder determines its added value. An iron remover shall be equipped before feeding to prevent iron debris from mixing into powder. Flotation can be applied after grinding for strict purity requirements.

Moisture Control: The moisture content of raw materials fed into the mill must be strictly controlled ≤1% to avoid wall sticking and blockage caused by excessive moisture.

Equipment Anti-corrosion: Due to the acid-sensitive property of calcite, acidic contact is prohibited during production. Neutral medium shall be adopted for cleaning and maintenance to eliminate corrosive residues on equipment.

How to Select Suitable Calcite Grinding Mill?

Raymond Mill

Raymond mill is the preferred equipment for producing 80~400 mesh medium-fine calcite powder. Its grinding roller and ring are made of high manganese steel and other wear-resistant materials. Equipped with front crusher and vibrating screen, it can effectively separate quartz mixed in calcite. It is suitable for small and medium-scale projects such as power plant desulfurization, building fillers, feed additives and glass raw materials.

Ultra-fine Grinding Mill

Ultra-fine grinding mill is the core equipment for producing 400~2500 mesh high value-added ultra-fine calcite powder. Among them, ultra-fine vertical mill adopts bed grinding principle with low metal abrasion, which minimizes iron pollution. It is especially suitable for high-end scenarios with strict requirements on powder whiteness and purity, such as high-end fillers for plastics, coatings, papermaking and rubber. The ultra-fine ring roller mill features relatively low investment cost, a cost-effective choice for small and medium ultra-fine powder production for ordinary industrial fillers of plastics and rubber.

Vertical Roller Mill

Vertical roller mill integrates crushing, drying, grinding and classification. It features large single-unit output and low power consumption, which is the preferred choice for large-scale calcite grinding projects with hourly output above 20 tons. It has strong drying capacity to process calcite raw materials with slightly higher moisture. The hydraulic roller lifting device facilitates maintenance of wear parts. It is widely used in large power plant desulfurization, sintering agent for steel plants and large building material bases.

Process Flow of Calcite Grinding Production Line

The calcite grinding line is designed to guarantee powder whiteness and purity. Raw calcite is coarsely crushed by jaw crusher to particle size ≤30mm for feeding, then screened by vibrating screen and de-ironed by iron remover to remove quartz and other impurities. After that, materials are fed into the grinding mill by feeder for grinding and classification. Coarse powder returns for regrinding, while qualified fine powder is collected by cyclone collector and pulse bag dust collector. Flotation can be added after grinding for deep purification to further improve whiteness, purity and product added value.

Application Scenarios of Calcite Grinding Mill

FAQ about Calcite Grinding

How to solve yellowish calcite powder output?

Yellowish powder is usually caused by impure raw ore or iron debris mixed in powder. Raw ore washing is available, and core grinding components can adopt high-chromium alloy wear-resistant material. Multi-stage iron removers can be equipped when needed.

Can Raymond Mill grind 600 mesh calcite powder?

The efficient grinding range of Raymond mill is 80~400 mesh. It can barely produce 600 mesh calcite powder with sharply reduced output and poor economy. If you already own a Raymond mill and need 600 mesh powder, an ultra-fine classifier can be matched. Generally, ultra-fine grinding mill is recommended.

What are the whiteness requirements for finished calcite powder?

Whiteness standards vary for different applications. Ordinary building materials and putty powder require whiteness ≥88, plastic masterbatch ≥92, papermaking coatings and high-grade plastics ≥94~96.