Talc is a widely used non-metallic minerals. However, in many fields of application in modern industry, purity, whiteness, particle size and distribution, surface properties (hydrophilic or hydrophobic, oil absorption, number of bacteria, etc.) are required to varying degrees. Therefore, for naturally occurring talc, although it is also possible to enter the market or trade, processing or deep processing is necessary for its application.
The deep processing of non-metallic minerals is a relative concept, and the so-called deep processing of talc is no exception. The connotation of deep processing will be enriched and updated with the advancement of science and technology and the development of modern industry. At present, we generally refer to talc's selective purification technology, superfine pulverization and fine grading technology, surface modification and sterilization technology, calcination technology, etc., and the corresponding equipment is called deep processing equipment. The so-called deep processing equipment is briefly introduced and reviewed below.
1. Selected Purification The reserves of natural high-purity talc are very limited. In order to meet the requirements of special applications, such as cosmetics, medicine, food and other fields, the purity of talc must be selected.
At present, the selection of high-purity talc in special fields is mainly based on the sorting method. In addition to manual sorting, other methods, such as photoelectric sorting, electrostatic sorting, selective screening, etc., must use the corresponding equipment.
Photoelectric detection is a method of sorting using the different optical properties of talc and impurity minerals. The photoelectric sorting machine is a sorting device with high degree of automation, which mainly includes the following parts: preparation mechanism (mine bin, feeder, belt conveyor); radiation source and detector (sensor): for control Circuit; actuator, etc. Using the characteristics of talc emitting white fluorescence under ultraviolet light, a relatively pure talc can be sorted by a photoelectric sorting machine, and a Soxex 621 type optical sorter is generally used.
Electrostatic separation is performed using a method of sorting magnesite and talc mine, a magnetic iron ore, magnetic pyrite, various minerals such as tremolite properties charge in the electrostatic field. Talc negative charge in the electrostatic field, magnesite ore belt positive charge, while magnetite and pyrite are a good conductor, which is easy to separate the above-mentioned minerals in an electric field. Electrostatic concentrators are also a highly automated sorting device.
Selective sieving is the use of talc and gangue minerals in terms of selective crushing and shape. The impact crusher and alternating use of rectangular and square sieves are used to separate most of the associated quartz and carbonate. mineral.
Magnetic separation and flotation are also one of the main selection methods for talc. The wet magnetic separation can reduce the iron content of talc concentrate from 4 to 5 % to less than 1%, and improve the whiteness of talc to some extent. Although the natural floatability of talc is good, talc used in cosmetics, medicine, food and other fields is generally not selected by flotation method.
In short, the selection of high-purity talc used in the fields of cosmetics, medicine, food, etc. in the industry is still dominated by manual sorting and photoelectric and mechanical picking, supplemented by magnetic separation and electric selection, and flotation is rarely used. The flotation of talc in China only stays at the laboratory level.
In some types of talc, sometimes talc graphite schist is associated. Due to the rich carbon content, the talc is dark gray or even black, which affects its application. The general method for purifying this talc is to calcine the ore at 1200 to 1300 °C, followed by sieving and strong magnetic separation. The higher the temperature, the higher the whiteness of the talc after calcination, and the whiteness of calcination can be up to 90 or more. At present, most of the calcining equipments use a shuttle kiln, a tunnel kiln and a rotary kiln.
2. Superfine pulverization Crushing is one of the most important processing techniques for talc. According to the fineness of the final product, the pulverization of talc can be divided into crushing (product particle size 3 3 ~ 5mm); fine grinding or fine pulverization (product particle size 10 ~ 150 mm); ultra-fine grinding or ultra-fine grinding (product particle size £ 10 mm ). The following is a brief introduction and review of the ultrafine grinding equipment.
Talc has a Mohs hardness of 1 and is the lowest hardness mineral with pulverizability.
The deep processing of non-metallic minerals is a relative concept, and the so-called deep processing of talc is no exception. The connotation of deep processing will be enriched and updated with the advancement of science and technology and the development of modern industry. At present, we generally refer to talc's selective purification technology, superfine pulverization and fine grading technology, surface modification and sterilization technology, calcination technology, etc., and the corresponding equipment is called deep processing equipment. The so-called deep processing equipment is briefly introduced and reviewed below.
1. Selected Purification The reserves of natural high-purity talc are very limited. In order to meet the requirements of special applications, such as cosmetics, medicine, food and other fields, the purity of talc must be selected.
At present, the selection of high-purity talc in special fields is mainly based on the sorting method. In addition to manual sorting, other methods, such as photoelectric sorting, electrostatic sorting, selective screening, etc., must use the corresponding equipment.
Photoelectric detection is a method of sorting using the different optical properties of talc and impurity minerals. The photoelectric sorting machine is a sorting device with high degree of automation, which mainly includes the following parts: preparation mechanism (mine bin, feeder, belt conveyor); radiation source and detector (sensor): for control Circuit; actuator, etc. Using the characteristics of talc emitting white fluorescence under ultraviolet light, a relatively pure talc can be sorted by a photoelectric sorting machine, and a Soxex 621 type optical sorter is generally used.
Electrostatic separation is performed using a method of sorting magnesite and talc mine, a magnetic iron ore, magnetic pyrite, various minerals such as tremolite properties charge in the electrostatic field. Talc negative charge in the electrostatic field, magnesite ore belt positive charge, while magnetite and pyrite are a good conductor, which is easy to separate the above-mentioned minerals in an electric field. Electrostatic concentrators are also a highly automated sorting device.
Selective sieving is the use of talc and gangue minerals in terms of selective crushing and shape. The impact crusher and alternating use of rectangular and square sieves are used to separate most of the associated quartz and carbonate. mineral.
Magnetic separation and flotation are also one of the main selection methods for talc. The wet magnetic separation can reduce the iron content of talc concentrate from 4 to 5 % to less than 1%, and improve the whiteness of talc to some extent. Although the natural floatability of talc is good, talc used in cosmetics, medicine, food and other fields is generally not selected by flotation method.
In short, the selection of high-purity talc used in the fields of cosmetics, medicine, food, etc. in the industry is still dominated by manual sorting and photoelectric and mechanical picking, supplemented by magnetic separation and electric selection, and flotation is rarely used. The flotation of talc in China only stays at the laboratory level.
In some types of talc, sometimes talc graphite schist is associated. Due to the rich carbon content, the talc is dark gray or even black, which affects its application. The general method for purifying this talc is to calcine the ore at 1200 to 1300 °C, followed by sieving and strong magnetic separation. The higher the temperature, the higher the whiteness of the talc after calcination, and the whiteness of calcination can be up to 90 or more. At present, most of the calcining equipments use a shuttle kiln, a tunnel kiln and a rotary kiln.
2. Superfine pulverization Crushing is one of the most important processing techniques for talc. According to the fineness of the final product, the pulverization of talc can be divided into crushing (product particle size 3 3 ~ 5mm); fine grinding or fine pulverization (product particle size 10 ~ 150 mm); ultra-fine grinding or ultra-fine grinding (product particle size £ 10 mm ). The following is a brief introduction and review of the ultrafine grinding equipment.
Talc has a Mohs hardness of 1 and is the lowest hardness mineral with pulverizability.
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