The chemical formula of calcite mineral, one of the carbonated rocks, is Caco3. Calcite and aragonitis are two separate crystal shapes of calcium carbonate. Calcite theoretically contains 56.03 %CAO and 43.97 %CO2. It is never pure in nature, but it is found in different rocks as a secondary mineral. In non -pure crystals, some of the calcium is displaced by Fe, Mg and MN.
Calsite is formed in the form of mineral vessels in nature and with lead, zinc, silver and other ores.
Calcite; When it contains colorless, transparent, purity when it contains different crystal-shaped, glassy brightness, transparent, transparent, transparent-half transparent, line color white-gray, glassy matte mineral in gray, yellow, brown, red, green, blue and black colors. Gray color is an indication that calcite contains carbon residues. It dissolves very quickly with HCI. It can be easily grinded. The color of the ground calcite is white. MOHS is 3 according to the hardness criterion and the density is between 2.6-2.7.
Calcite production
Calcite is usually produced by open operation method. In terms of reserves, in poor countries, enrichment by underground enterprises and flotation is also performed to produce high whiteness and purity ore.
The calcite is washed before flotation and it is cleaned from the impurities such as clay and mud and grinded below -74 µ. After the grinding with a cyclone working with a closed circuit, the material of the material is taken.
Pulp containing 20 %times for flotation is prepared. Calcite fatty acids and soap are floated in pH 8.5-9. Serisite, quartz and other silicates are suppressed with tannic acid, queebracho or kalgon. Na2CO3 and NA2Sio3 are used as a collector. Flotation time lasts up to 10-12 minutes.
When the calcite is found together with the apatitis and wateritis, the reverse flotation is applied and the calcite is dipped and the impurities are floated.
Artificial calcit production
Calcite does not occur in each bed of the desired purity and whiteness. For this reason, CAO is obtained by calculating at high temperatures.
Caco3 → Cao + CO2
In a closed reactor, which is formed by mixing CAO with water, some chemicals under pressure are added and CO2 gas is passed through:
CAO + H₂O → CA (OH) 2
CA (OH) 2 + CO2 → CACO3 + H₂O
In this process, artificial and pure calcite crystals are formed with grain size of 1-3 µ and whose crystal shape can be controlled. CO2, which is necessary for the method, is usually a waste of waste in paper and cellulose production facilities. The production facility for this product, which will be used as filling and bird coating in the paper sector, is established near the paper factories. Although the cost is higher than the aqueous ground calcite, the quality is higher.
Dry production of calcite
Exterior paints, state base filling and various filling purposes to be used for 100 µ, paint, plastic, paper, chemistry and so on. Calcites used in areas should also be grinded to 40 µ.
It is grinded to 5.0-10 cm in luster crushers with calcite chin, 3 mm with hammer crushers and to -100 µ in ball mills. In the last stage dry grinding, the calcite is sized and marketed by bagging.
In the ball mills, vertical mixed mills are used for more fine grinding of -100 µ.
Juicy grinding of calcite
In order to be used in bird coating and paint production in the paper industry, the D90 <2 μ size should be grinded. The amount of energy and unit grinding costs used in fine -sized grating are very high. A significant portion of the energy used is released as heat. It is necessary to grind water in order to teach the dryly grinded calcite to approximately 40 µ. In mixed vertical ball mills, there is the possibility of grinding the calcite of the bonus with 75 %of ceramics or zircon balls to -2 µ. The ground calcite is dried and marketed by bagging.
Since the capacity of the mixed vertical ball mill and the grinding conditions required for this capacity have been determined earlier, this mill operates open circuit. The capacity of fine grinding circuits is low. A rolled mill can feed a few vertical ball mills with a mixture.
Calcite standards
Although Calcite size distribution and whiteness criterion is not available, there is no standard. Users prepare a specification that contains the calcite properties they need and use them in accordance with these features. The most important characteristics of calcite are whiteness, size distribution, humidity, oil absorption feature and resolution in different environments.
The abrasion of calcite is the weight loss as milligrams caused by the abrasion device of the 100gr dry Caco3 mixture with 3.2 lt pure water.
Caco3 grains are used in the environment in which it is used. This feature stands out when used for filling purposes.
In other words, the activation of the calcite is the process of coating the gap between Caco3 grains to reduce and reduce the gap with various alipheatic chemicals.
The degree of whiteness. The light of the material is the degree of reflection of the material based on MGO whiteness. This value is required to be higher than 96 % for calcite.
Elrepho whiteness in the paper industry is measured by spectrometer, the color, brightness, opaque and whiteness of the calcite are measured.
Calcite usage areas
Calcite color, chemical structure CaCO3, chemical purity, cheapness and other features due to paint, paper, plastic and so on. It is used as a filling material after grinding in many sectors in micronized dimensions.
Calcite used in the paint sector should be grown to -20 µ. Calcites reduces the cost of dyes prepared with these pigments by providing less use of very expensive pigments such as titanium dioxide. In construction paints, 25-35 % calcite is added to water-based paints in internal and tooth coating.
Watery grinded calcite with a size of D90 <2 µ is used for filler purposes in the paper sector, D90 <2 µ in size, with a watery grinded calcite in size. In wallpapers and cardboard production, micronized calcite is added to cellulose between 15-30 %. Kaolin has been replaced by the paper sector due to its high whiteness, cheapness and other physical characteristics it gained. The yellowing seen in the paper produced by alkaline system was prevented and it became possible to use more calcite filling than kaoline.
The calcite size used in the plastic sector is between 1.0-20 µ. Calcite is mixed with polymers and used as filling and coating materials in construction, plastic, carpet base, linoleum, furniture and automotive sector. The coating is mostly made with stearic acid and sometimes with calcium stearate.
In the construction sector, calcit is used as ready -made plaster and white filling in the paste. White colored, cement -based plaster and pastes are mixed with powder polymers and applied as coarse plaster, thin plaster, paste to the wall.
Micronized calcite biscuits, bread, gum and similar foodstuffs are also used as a source of chemical purity, cost of cost and calcium.
Although calcite in the ceramic sector is low, it is grinded in 40-100 µ and then participates in ceramic recipes.
