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Chalk Powder Processing Machinery: Chalk Crushers And Chalk Mills

Date:2021-10-20 06:38:48

Chalk is a softer limestone (a kind of carbonate rock). Chalk is a variant of calcite, the main component is calcium carbonate (CaCO3). It is formed by the accumulation of the remains of ancient creatures. White, soft, and widely distributed. Chalk, which is a mineral, is generally used to make chalk and paint materials.


Uses of chalk

The chalk is white in color and highly dispersible. The particles are round in shape, fragile and have little water absorption. The chemical properties are unstable, and the particles are small, generally below 10mm. It has poor cementation and is easy to crush. It has strong coating ability and high oil capacity, and its oil absorption is 20%-25% of the chalk itself. Utilizing the above characteristics, chalk is widely used in rubber, papermaking, paint, plastics, pigments, coatings, ceramics, sugar, casting, as well as putties, sealants, etc. In areas lacking limestone, some impure chalk can also be used as a raw material for cement.

Rubber industry

Chalk can be used as a filler in the rubber industry. The industrial requirements are:
Granularity No. 325 sieve (16900 holes/cm2) sieve residue <0.2%-1%;
Ignition loss is 40%-46%;
Chemical composition CaC03 ≥ 90%-95%, Fe ≤ 2.3%-1%, Mn ≤ 0.004%-0.04%, H20 ≤ 0.1%-0.4%, alkalinity ≤ 0.01 %一1.0%.

Pigment Industry

Make use of chalky whiteness and oil absorption capacity as supplements and fillers in paints, pigments and coatings. The industrial requirements are:
Granularity No. 325 sieve sieve residue <0.5%;
Density 2.65-2.75 g/cm3;
Chemical composition CaC03≥91%, MgO≤2%, Si02≤0.5%, Fe203≤0.05%,

For linseed oil and putty

Linseed oil putty is a paint for making oilstone and raincoat. The requirements are as follows:
CaC03≥95%, insoluble matter in hydrochloric acid≤3.5%, Fe203+FeO10Ai203≤0.8%

Ceramic industry

CaC03>96%, Si02<2%, Fe03<0.25%, S02<0.1%.

Distribution of chalk

The chalk is mainly found in the Cretaceous strata on both sides of the English Channel. France, the United States and the former Soviet Union are rich in chalk. There are no reports of large-scale chalk deposits in China. Chalk is only found in the Quaternary or Tertiary in Sichuan, Henan and other places. The deposit is small in scale and low in quality,

Chalk powder processing equipment

The preparation and processing of chalk is inseparable from crushing equipment and milling equipment, so chalk crushers and chalk mills are the two most important equipment in the production of chalk powder.
Chalk has a hardness of 3, which is a low-hardness mineral. Many crushing equipment can be used, such as jaw crushers, cone crushers and impact crushers.
Among them, the chalk jaw crusher is the most commonly used. The jaw crusher relies on the movable jaw plate to periodically reciprocate the fixed jaw plate to achieve the crushing effect. The crushing cavity of the equipment is deep and there is no dead zone, which is different from the traditional jaw that has not been improved. Compared with the type crusher, the feed capacity and output are improved, and the adjustment range of the discharge opening becomes larger, which can meet more production requirements of different users. In addition, the equipment can save energy by 15% to 30% and double the energy of the system. Above, there is no noise, stable production, and it can break the chalk well, laying a good foundation for its subsequent processing.

Selection of chalk grinding mills

There are many kinds of milling equipment commonly used for chalk milling, among which the more popular ones are Raymond mills, high-pressure suspension roller mills and ultra-fine mills.

Chalk Raymond Mill

Raymond mill is a kind of grinding equipment widely used in the market. It has a very significant effect on the grinding of chalk and has the following advantages.
1. Using vertical structure, small size, light weight, easy to move, and the complete set of equipment performance is still very strong, from chalk powder to chalk powder packaging can be completed independently, without the help of other auxiliary equipment to complete the effect It's also very good.
2. The screening efficiency is very high. Compared with other milling equipment, the screening efficiency of this equipment can reach 99%, which is not available in other equipment.
3. The wear-resistant parts are made of extra-hard wear-resistant materials, which greatly improves the wear resistance of the entire equipment, runs more smoothly, and extends the replacement cycle of wear-resistant parts.
4. In the process of continuous chalk work, the probability of equipment failure is very low, which reduces the customer's operating costs accordingly.

chalk powder Raymond mill

Chalk High-pressure Suspension Roller Mill

The working principle of the high-pressure suspension roller mill is similar to that of the Raymond mill, but the grinding device is equipped with a high-pressure spring with a pressure of 1000-1500 kg.
When the machine is working, under the action of high-pressure spring and centrifugal force, the grinding roller rolls in close contact with the grinding ring, and its rolling pressure is 1.2 times higher than that of the Raymond mill under the same conditions, and the output can be increased by 20%-30%; After the grinding roller and the grinding ring reach a certain amount of wear, adjust the length of the high-pressure spring to maintain a constant grinding pressure between the grinding roller and the grinding ring, so as to ensure a stable output and fineness.

Chalk high-pressure suspension roller mill

Chalk Ultrafine Grinding Mill 

HGM ultrafine grinding mill is also called three-ring/four-ring ring roller grinding mill. There are three or four layers of grinding rings for ultra-fine grinding, with a total of 18-44 grinding rollers.
HGM ultrafine grinding mill can process 150-3000 mesh ultra-fine powder. Especially for the grinding of ultra-fine powder above 325 mesh, it has absolute advantage.
The chalk ultrafine grinding mill has the following advantages.
1. High efficiency and energy saving
In the case of the same fineness of the finished product and the same motor power, the output is more than double that of jet mill, stirring mill, and ball mill.
2. Long service life of wearing parts
The grinding roller and grinding ring are forged with special materials, which greatly improves the utilization. In the case of the same fineness of materials and finished products, the service life is 2-5 times longer than the wear parts of impact crushers and turbo crushers, generally up to more than one year. When processing calcium carbonate and calcite, the service life can be up to 2 -5 years.
3. High safety and reliability
Because there is no rolling bearing and no screws in the grinding cavity, there is no problem that the bearings and their seals are easily damaged, and there is no problem that the screws are easy to loosen and damage the machine.
4. High product fineness
The fineness of the product can reach D97≤5μm at one time.
5. Environmental protection and clean
The pulse dust collector is used to capture dust, and the muffler is used to reduce noise, which is environmentally friendly and clean.
Chalk high-pressure suspension roller mill
Further reading:

The difference between chalk and limestone:

Both chalk and limestone are composed of calcium carbonate.
It cannot be distinguished from the chemical composition.
The difference is that the chalky soil is soft in texture.
Chalk powder can be used to make many useful products, such as high-quality chalk, putty, paint, medicine, paper, toothpaste and gunpowder. Generally not used in the production of cement!


How is chalk formed?

Above the sea, there are many tiny animals and plants floating. Among them is a single-celled animal called "multiple blasthole". The shells of these creatures are made of lime. When these organisms died, their extremely tiny bodies sank to the bottom of the sea. Over time, it will accumulate into a thick layer of shells. Of course, this process will take millions of years to complete. This layer of things gradually bonded together and compressed into a soft limestone, we call it "chalk soil". Chalky soil is a fine sediment of calcium carbonate, mainly composed of the remains (coccoliths) of single-celled plankton [coccoli-thophorid].
As we all know, due to various crustal movements on the earth's surface, the land that was originally underwater often becomes dry land. The area along the English Channel is such a place. The chalky soil layer on the seabed was lifted up. Afterwards, those soft parts were washed away by water, leaving behind a huge chalky rock wall. Among them, the two most famous chalk walls are Dover in England and Dipa in France on both sides of the English Channel.
Chalk is a kind of loose earthy calcite or limestone, the main chemical component is CaCO3, the main mineral component is biological micrite calcite, the texture is purer, the calcite content can reach more than 99%,
It often contains impurities such as quartz, feldspar, clay minerals and sea green stone. According to the color and degree of cementation, chalk can be divided into four types: white chalk (CaCO3 content reaches 99), marl chalk, chalk-like limestone, and glauconite chalk.

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