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What is limestone

Limestone which is mainly made up of calcium carbonate(CaCO3)is largely used as building material & industrial raw materials. Limestone can be directly processed into aggregated rock and burnt into unslaked lime which becomes slaked lime after its moisture & water absorption. The main content of slaked lime is Ca(OH)2. Slaked lime can be blended into lime slurry, lime putty, lime mortar etc. Which can be used as coating material, brick & tile adhesive. Limestone is the main raw material of glass production.  Calcium carbonate can be directly processed into aggregated rock and burnt into unslaked lime. There are two types of lime: unslaked lime and slaked lime. Unslaked lime is lumpy, its main content is CaO, pure unslaked lime is white, unslaked lime with impurities is light gray or light yellow. Cement is made from mixture of limestone and clay etc. by high temperature calcining.

limestone of Application

Limestone mill grinds limestone into powder, limestone powder has different specifications:

  • It can be used to produce anhydrous calcium chloride which is the main auxiliary raw material of sodium dichromate production. It is the main raw material of glass & cement production, it also can be used in the areas of building materials and poultry feed.
  • It is the raw material of glass & anhydrous calcium chloride, it can be used as white filler of rubber & oil paint, it also can be used in building area.
  • It can be used as filler of plastics, coating putty, coating material, oil paint, plywood.
  • It can be used as filler of wire insulation layer & rubber molded parts & asphalt felt.
  • It can be used as desulphurizing absorbent for flue gas desulphurization in power plant.
The model selection & process flow of limestone powder making equipment

Limestone powder for desulphurization in power plant is the most widely used in the market.

Component analysis of limestone raw material

CaO MgO Al2O3 Fe2O3 SiO2 so3 burning amount loss amount
52.87 2.19 0.98 1.08 1.87 1.18 39.17 0.66

Remarks: limestone in different areas differs greatly, limestone with high content of SIO2, Al2O3 is very difficult to grind.

The model selection scheme of limestone powder making main engine

Product specification(mesh) 95%particles’ grain size is over 200meshes 90% particles’ grain size is over 250meshes 90% particles’ grain size is over 325meshes,
model selection scheme
  • Vertical mill or large scale Raymond mill

1.Power consumption: 18~25kWh/ton, it differs according to different materials and product requirements.

2.Selecting main engine according to output & grain size.

3.Main application: desulphurization in power plant, blast furnace smelting solvent etc.

The analysis of different types of mills
  • 1.Pendulum mill(R、HC、HCQ):

    It can grind coarse powder whose grain size is under 600 meshes, low investment cost, low energy consumption.

  • 2.Vertical Roller mill(HLM、HLMX):

    It can meet the demand for large scale production, high output, good stability. Disadvantage: high investment cost.

  • 3.Ring roller mill(HCH):

    It can produce ultrafine powder, low energy consumption low investment cost, large scale ring roller mill has good market prospect. Disadvantage: low output.

  • 4.Ball mill +classifying:

    High energy consumption, it is almost obsolete in nonmetallic mineral industry.

The process flow of limestone powder production

The first stage: raw material crushing

Limestone raw materials are crushed into small lumps whose grain size is 15mm-50mm.

The second stage: grinding

The crushed small limestone lumps are conveyed to the storage hopper by elevator, then a certain amount of the small limestone lumps are evenly conveyed to the grinding chamber by the feeder.

The third step: classifying

The ground material powder is classified, and the unqualified powder returns to the main engine to regrind.

The fourth step: collection of finished product

The qualified powder is blown through the pipes to the dust collector, the collected powder is conveyed to the storage bin from the discharge outlet, then the powder is packed up by automatic packing machine or loaded into powder tank truck.

We provide a complete set of solution scheme and worry free services.
Classic cases:

customer on site


Material: limestone

Grain size: 325meshes D97

Output: 8-10t/h

Device: one HC1300

Customer’s feedback

The output of HC1300 mill is almost 2 tons more than that of 5R mill when they produce powder of the same specification, while the energy consumption of HC1300 mill is lower. The whole system is automatic, workers operate the mill in central control room; simple operation, low labour cost and low running cost, hence the mill is very competitive; in addition, the services such as design, installation instruction, adjusting & testing are all free.

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