Introduction to processing technology of talc

1. The ore dressing method for purifying talc is as follows:

1) flotation because the natural buoyancy of talc is good, the hydrocarbon oil collector can be flotation. The commonly used collector is kerosene, the flotation oil as the foaming agent. The foam produced by methyl isobutyl methanol (MIBC) is brittle and easy to obtain high quality concentrate. The floatation process of talc is simple, and the final concentrate can be obtained by only one roughing, one sweep, and two or four handpicking.

2) manual selection is based on the slimy properties of talc and gangue minerals. Talc has good slime, the higher the grade, the better the slime, easy to identify by hand. Most talc mines in China are used to produce high grade talc blocks by hand.

3) in addition to talc, there are also minerals such as magnesite, magnetite, magnetite, diorite and so on in the talc ore of electrostatic separation. The microchimeric size is about 0.5mm. In electrostatic field, talc is negatively charged and magnesite is positively charged, while magnetite and magnetite are good conductors, so it is easy to separate the above minerals in electric field.

4) in addition to a certain degree of fineness, there must be a certain degree of whiteness in the magnetic concentrate of talc. Because of the presence of chromatite in ore, sometimes the above method is not enough, so it is necessary to remove the iron ore by magnetic separation. Wet magnetic separation can reduce the iron content of talc concentrate from 4% to 5% to less than 1%.

5) photoelectric selective photoelectric detection is a method of separating the surface light of talc and impurity mineral with different academic properties. Photoelectric separator includes preparation mechanism (ore bin, feeder, belt conveyor), radiation source and detector (sensor), electronic control circuit and actuator.

In addition, the characteristics of white fluorescence produced by talc under ultraviolet irradiation can be used to select the pure talc by photoelectric separator. Generally adopt labor Tex type 621 light separator, such as the United States Cyprus talc company use this method to the lean ore enrichment of talc content and 30% to the talc content up to 69% of the rich ore, the final grinding fine flotation to 200 mesh, get grade 99% grade cosmetics talc.

6) selective crushing and screening using talc and gangue minerals in selective crushing and shape differences, impact crushing and alternate using rectangular screen to the frontier with square sieve sieve method, can isolate most associated quartz and more than half of carbonate minerals.

2. Fine grinding and ultrafine grinding of talc are eventually applied in the state of powder. Therefore, fine grinding and ultra-fine grinding are necessary processing technologies for talc.

The mohs hardness of talc is 1, which is natural and grindable. Fine grinding of talc, various types of commonly used domestic Raymond mill (i.e., hanging roller mill), the main production 200 mesh and 200 purpose products, but if set fine grading equipment, can produce 500-1250 purpose products.

Ultrafine talc powder is one of the most used ultrafine powder products in the world. It is widely used in paper making, plastic, rubber, paint coating, cosmetics, ceramics and so on.

At present, the processing of ultrafine talc powder mainly adopts dry process. Wet crushing has been studied, but it is seldom used in industry. The dry production equipment mainly includes high speed mechanical impact mill, air flow mill, centrifugal self-grinding machine, spinning mill, vibration mill, mixing mill and tower mill. Besides airflow crusher, in order to meet the requirements of users on the particle size distribution, general also need other classifying equipment configuration fine grading equipment, equipment in fine classification is all sorts of turbine centrifugal air classifier, such as MS, MSS, ATP, LHB, etc.

Airflow crushing process of talc is as follows:

Talc - coarse - dry - medium - fine grinding (ramon grinding) -

Ultrafine crushing (airflow grinding) - cyclone aggregates - packaging

The production process is that the talc blocks are first broken by feeding machine into hammer crusher. The broken material is dried by bucket elevator and vibration feeder into vertical dryer. After the dry material is broken by the hammer crusher, the talc powder after the fine grinding of ramon mill enters the air flow mill for ultra-fine crushing. The final product fineness can reach 500-5000 mesh (d97= 30-5um).

Airflow grinding used in industry includes disc type airflow grinding, fluidized bed airflow grinding, circulating pipe airflow grinding, etc.

The high speed mechanical impact ultrafine crushing process of talc is as follows:

Talc - crushing (hammer crusher) - high speed mechanical impact ultrafine crusher -

Turbine - type fine classifier - cyclone aggregates - packaging

Generally, the talc is broken to 8mm and then directly fed into the mechanical impact ultrafine grinder. After crushing, the products are sorted by the turbine fine classifier and collected by the cyclone concentrator. The refined product can be returned to the grinding machine or can be used as a separate product.

The ultra-fine grinding process of centrifugal self-grinding and rotary grinding machine of talc is similar to that of high-speed mechanical impact ultra-fine grinding.

3. Surface modified talc powder is widely used as reinforcing filler for polypropylene, nylon and other high polymer matrix composite materials. Surface modification can effectively improve the affinity between talc powder and polymer and the dispersion state of talc powder filler in high polymer substrate, so as to improve the physical and mechanical properties of composite materials.

The surface modifiers used in the surface modification of talc powder mainly include various surfactants, paraffin wax, titanate and zirconium aluminate coupling agents, silane coupling agents, phosphatides, etc.

The main modification process is dry modification. The modification machines mainly include continuous and fluidized modification machines, continuous eddy current powder surface modification machines (SLG type), high speed heating mixed kneading machines, etc.

4. There are abundant black talc resources in guangfeng area of jiangxi province. The reason is that some talc ores contain more organic carbon. In order to develop and utilize these resources, calcining is a necessary process. Calcination temperature is 600-1200 ℃, the temperature range, the higher the temperature, the higher the whiteness of the talc after calcining, calcined whiteness of up to more than 90%. At present, most of the calcining equipment adopts soxhlet kiln, tunnel kiln and rotary kiln.

Talcum powder