electromagnetic separator
PTMS MAGNETIC SEPARATOR
what is magnetic bead separation ？
Kaolin is mainly aluminosilicate, the main component is AL2(Si2O5)(OH)4, or it is written as Al2O3·2SiO2·2H2O. Some of the trace elements of metal will be different colors, specific colors and flames of this metal element. The reaction color or its metal oxide color is the same.
1. Whiteness is one of the main parameters of kaolin's process performance, and kaolin with high purity is white. Kaolin whiteness is divided into natural whiteness and self-degree after calcination. For ceramic raw materials, the whiteness after burning is more important, and the higher the whiteness of calcination, the better the quality. The ceramic process stipulates that the drying temperature of 105 ° C is the classification standard of natural whiteness, and the calcination of 1300 ° C is the classification standard of the whiteness of calcination. The whiteness can be measured by a whiteness meter. A whiteness meter is a device that measures the reflectivity of light at 3800 to 7000 A. In the whiteness meter, the reflectance of the sample to be tested is compared with the reflectance of the standard sample, that is, the self-degree value. Brightness is a process property similar to self-degree, equivalent to the self-degree of 4570A wavelength illumination. The color of kaolin is mainly related to the metal oxides or organic matter contained therein. Generally, Fe2O2 is reddish brown and brownish yellow; Fe2+ is light blue, light green, and MnO2 is light brown; while organic matter is yellowish, gray, green, black and other colors. The presence of these impurities reduces the natural whiteness of the kaolins, in which iron and titanium minerals also affect the self-degree of calcination, causing stains or melting of the porcelain.
2. Particle Size Distribution Particle size distribution refers to the proportion (in percent) of particles in natural kaolin in a given range of different particle sizes (represented by the mesh of millimeter or micron mesh). The particle size distribution characteristics of kaolin are of great significance for the selectivity and process application of ore. The particle size has a great influence on its plasticity, mud viscosity, ion exchange performance, forming properties, drying performance and firing performance. Kaolin mines require technical processing and are easy to process to the required fineness of the process. It has become one of the criteria for evaluating ore quality. Each industrial sector has specific particle size and fineness requirements for kaolin for different uses. For example, the content of kaolin used as a coating in the United States is less than 2 μm, accounting for 90-95%, and the papermaking filler is less than μm, accounting for 78-80%.
3. The clay formed by the combination of plastic kaolin and water can be deformed under the action of external force, and the plasticity can be maintained after the external force is removed. Plasticity is the basis of the molding process of kaolin in the ceramic body, and is also the main process technical index. The plasticity index and the plasticity index are usually used to indicate the plasticity. The plasticity index refers to the liquid limited water content of the kaolin clay minus the plastic limit moisture content. The plasticity index represents the forming property of the kaolin clay. The load and deformation of the mud ball under pressure and crushing can be directly measured by a plasticizer. It is expressed in kg·cm. The higher the plasticity index, the better the forming property. The plasticity of kaolin can be divided into four levels.
4. Combinational binding refers to the combination of kaolin and non-plastic materials to form a plasticized mud mass with a certain dry strength. The binding ability is determined by adding standard quartz sand to kaolin, and judging the highest sand content and the flexural strength after drying to maintain the plastic mud mass. The more sand is mixed, the more The stronger the kaolin binding ability. Generally, kaolin has strong binding ability.
5. Viscosity and thixotropic viscosity refers to a feature in the interior of a fluid that hinders its relative flow due to internal friction. Its viscosity is expressed in terms of its internal friction (acting on 1 unit area), and the unit is Pa·s. The viscosity is generally measured by a rotational viscometer in terms of the rotational speed of the kaolin slurry containing 70% solids. In the production of 1 art, viscosity is of great significance. It is not only an important parameter of the ceramic industry, but also has a great influence on the paper industry. According to the data, the use of kaolin as a coating abroad requires a viscosity of about 0.5 Pa·s at low speed coating and less than 1.5 Pa·s at high speed. Thixotropy refers to the property that the mud that has thickened into a gel and no longer flows becomes a fluid after being stressed, and then gradually thickens into a state after being static. The size is indicated by a thickening coefficient and measured by an outflow viscometer and a capillary viscometer. Viscosity and thixotropy are related to the mineral composition, particle size and cation type in the mud. Generally, the montmorillonite content is large, the particles are fine, and the exchangeable cation is mainly sodium, and its viscosity and thickening coefficient are high. Therefore, it is common to add clay with strong plasticity, improve the fineness and the like to improve the viscosity and thixotropy of the process, and reduce it by increasing the dilution of electrolyte and moisture.
6. Drying performance Drying performance refers to kaolin clay: performance during shame drying. Including dry shrinkage, drying strength and drying sensitivity. Dry shrinkage refers to the shrinkage of kaolin clay after dehydration and drying. The kaolin clay is generally dehydrated and dried at a temperature of 40 to 60 ° C and not more than 110 ° C. Due to moisture discharge, the particle distance is shortened, and the length and volume of the sample are contracted. The shrinkage shrinkage of the dry shrinkage line is expressed as a percentage of the change in length and volume after the kaolin meal is dried to constant weight. The drying line shrinkage of kaolin is generally between 3 and 10%. The finer the particle size, the larger the specific surface area, the better the plasticity, and the greater the drying shrinkage. The same type of kaolin has different shrinkage due to the different blending water, and many of them have large shrinkage. In the ceramic process, the drying shrinkage is too large, and the green body is liable to be deformed or cracked. Dry strength refers to the flexural strength of the mud after drying to constant weight. Dryness sensitivity refers to the degree of difficulty in deformation and cracking tendency when the green body is dried. High sensitivity, easy to deform and crack during drying. Generally, kaolin having high drying sensitivity (drying sensitive chamber coefficient K>2) is liable to form defects, and the lower one (drying sensitivity coefficient K<1) is comparative to nitrogen in drying.
7. Sinterability Sinterability refers to a property in which a solid powdered kaolin body is heated to a temperature close to its melting point (generally exceeding 1 000 ° C), and the material spontaneously fills the inter-particle gap to be densified. The state in which the porosity decreases to the lowest value and the density reaches the maximum is called the sintered state, and the corresponding temperature is called the sintering temperature. When heating is continued, the liquid phase in the sample increases continuously, and the sample begins to deform. At this time, the temperature is called the conversion temperature. The interval between the sintering temperature and the conversion temperature is called the sintering range. Sintering temperature and sintering range are important parameters in the ceramic industry to determine the billet formulation and select the type of kiln. The sample has a low sintering temperature and a wide sintering range (100 to 150 ° C). The sintering temperature and sintering range can be controlled by blending the fluxing raw materials and mixing different types of kaolin in proportion.
8. Sintering shrinkage and shrinkage means that a series of physicochemical changes occur during the calcination of the dried kaolin billet (dehydration, decomposition, mullite formation, melting of fusible impurities to form a glass phase filled in the particles) The gap between the two, etc., and the performance of the product shrinkage is also divided into two types: line shrinkage and body shrinkage. Like the dry shrinkage, the firing shrinkage is too large, which tends to cause cracking of the green body. In addition, when calcined, if a large amount of quartz is mixed in the billet, it will undergo crystal transformation (trigonal to hexagonal), causing its volume to expand and also causing back shrinkage.
9. Fire resistance Fire resistance refers to the ability of kaolin to resist melting at high temperatures. The temperature is called refractoriness when softening occurs at high temperature and melting begins. It can be directly measured by standard temperature measuring cone or high temperature microscopy, and can also be calculated by M.A. Belzburgov empirical formula. The degree of refractoriness is related to the chemical composition of kaolin. The refractoriness of pure kaolin is generally around 1 700 °C. When the water mica and feldspar content are high, the potassium, sodium and iron content are high, the refractoriness is lowered, and the kaolin's refractoriness is the lowest. Less than 1500 ° C. The industrial sector specifies R for refractory materials. The O content is less than 1.5-2% and the Fe zO s is less than 3%.
10. Suspension and Dispersibility Suspension and dispersibility refer to the property that kaolin is difficult to precipitate when dispersed in water. Also known as deflocculation. Generally, the finer the particle size, the better the suspension. Kaolin used in the enamel industry requires good suspension. Generally, the suspension performance of a sample dispersed in water is determined by a settling time for a certain period of time.
1 1. Optional Optional means that the kaolin ore is hand-selected, machined and chemically treated to remove harmful impurities and to achieve the desired quality of the industry. The selectivity of kaolin depends on the mineral composition, state of occurrence, particle size, etc. of the harmful impurities. Quartz, feldspar, mica, iron, titanium minerals, etc. are all harmful impurities. Kaolin mineral processing mainly includes sand removal, iron removal, sulfur removal and other projects. The specific method will be introduced in the mineral processing section.
1 2. Ion-adsorbing and exchangeable kaolin has the property of adsorbing various ions and impurities from the surrounding medium, and has weak ion exchange properties in the solution. The pros and cons of these properties are mainly determined by the main mineral components of kaolin.
13. Chemically stable kaolin has strong acid resistance, but its alkali resistance is poor. Using this property, it can be used to synthesize molecular sieves.
14. Electrically insulating high-quality kaolin has good electrical insulation, and this property can be used to make high-frequency porcelain and radio porcelain. The electrical insulation performance can be measured by its electrical breakdown resistance.
