How to remove impurities in silicon carbide products?

There are two methods: chemical iron removal method and physical iron contact method, and the following one will take a look at the specific process.

Chemical Iron Removal Method:Because silicon carbide is chemically stable and difficult to react with other substances, while iron is easier to react with other substances, we can use this to remove iron from the reaction. The iron in silicon carbide powder is mainly in the form of ferric oxide.

So what we mainly remove is ferric oxide, ferric oxide is alkaline chloride, which can be dissolved in acid by reacting with acid, silicon carbide powder is insoluble in acid, after the reaction, we collect the bottom silicon carbide powder, we use this method to iron in silicon carbide powder.

Physical Iron Touch Method:The iron element in silicon carbide powder can be removed by physical method, and the iron present in the differential can be selected by magnetic separator equipment, so as to achieve the effect of iron removal, but the effect of this method is not particularly good. There is also a direct solution in the grinding equipment, the production of SX-88 ultra-fine mill equipment using a new process, fineness can be adjusted at 500-5000 mesh, professional silicon carbide micro powder mill equipment, in which we can change the raw materials of the equipment to reduce the pollution of ferric oxide in the processing of the equipment, the use of stainless steel materials, directly at the source of production to reduce the pollution of ferric oxide.

The first is the pickling of silicon carbide. Pickling is usually done by treating the silicon carbide particles with sulphuric acid under heated conditions. Its main purpose is to remove impurities such as metallic iron, iron oxide, magnesium, aluminum and other impurities in silicon carbide.

The second is the alkaline washing of silicon carbide. The alkali washing of silicon carbide is usually also in the process of heating silicon carbide, and the silicon carbide particles are treated with sodium hydroxide. The main purpose is to remove free silicon, silica and other substances on the surface, which can increase the content of silicon carbide.

First of all, let's talk about the pickling of silicon carbide. Pickling is usually done under heated conditions and treated with sulfuric acid to the silicon carbide particles, the main purpose is to remove the impurities such as metallic iron, iron oxide, magnesium, aluminum and so on in the silicon carbide. In this way, it can remove impurities in silicon carbide very cleanly and conveniently.

The second is the alkaline washing of silicon carbide. The alkali washing of silicon carbide is usually under the condition of heating, and the silicon carbide particles are treated with NaOH, the main purpose is to remove the free silicon, silicon dioxide, etc. on the surface, so as to improve the content of silicon carbide and strengthen its silicon carbide content. If there is anything you don't understand, you can go to the refractory brick trading network to take a look.

First of all, let's talk about the pickling of silicon carbide. Pickling is usually done under heated conditions to treat silicon carbide particles with sulfuric acid, the main purpose is to remove impurities such as metallic iron, iron oxide, magnesium, aluminum and so on in silicon carbide. This cleanly and quickly removes impurities from silicon carbide.

The second is the alkaline washing of silicon carbide. The alkali washing of silicon carbide is usually under the condition of heating, and the silicon carbide particles are treated with NaOH, the main purpose is to remove the free silicon, silica, etc. on the surface, which can increase the content of silicon carbide and strengthen its silicon carbide content. Of course, this is only the most commonly used method at present, and it has been found in practice that the production efficiency of silicon carbide can be better improved.

If you want to remove its impurities, you need to pickle it, and the main steps are:

First of all, the pickling of silicon carbide. Pickling is usually carried out under heated conditions, with sulfuric acid to treat silicon carbide particles, the main purpose of which is:

In order to remove metal iron, iron oxide, magnesium, aluminum and other impurities in silicon carbide, it can be very clean and convenient to remove impurities in silicon carbide;

Secondly, alkali washing of silicon carbide. The alkali washing of silicon carbide is usually under heating conditions, and the silicon carbide particles are treated with NaOH, main.

The purpose is to remove the free silicon, silica, etc., so as to improve the content of silicon carbide and strengthen its silicon carbide content.

The hybrid mode of silicon and carbon is as follows:

In silicates, the hybrid mode of silicon atoms is sp3 hybridization of lead, in which four atomic orbitals (s, px, py, pz) form four equivalent sp3 hybrid orbitals through hybridization, and these orbitals form four covalent bonds with four oxygen atoms, so that the silicon atoms are fixed in the tetrahedral configuration.

In carbonates, the hybridization mode of carbon atoms is sp2 hybridization, in which three atomic orbitals (s, px, py) form three equivalent sp2 hybrid orbitals by hybridization, and these orbitals form three covalent bonds with the three excitation front oxygen atoms, so that the carbon atoms are fixed in a planar configuration. At the same time, the fourth atomic orbital (pz orbital) of the carbon atom is unhybridized and forms a bond with another oxygen atom, giving the carbonate molecule a mixed bonding property of double and single bonds.

Summary. Hello dear.

1. Light pollution: The production process requires ignition operation, that is, the smelting furnace body is burned and smelted in the open air, and there is fire, if it is a residential area nearby, it will definitely affect the daily rest of residents. However, air pollution is the mainstay, as for how far the harm is, depending on the wind direction where the plant is located, such smelting projects are not allowed to be approved now, and they are national restricted projects.

2. Air pollutants: dust, smoke, carbon monoxide (a small amount), carbon dioxide (a large amount), according to the impurities contained in the raw materials used, it may also contain sulfur dioxide, nitrogen oxides, etc.

3. Water pollution: mainly due to high salinity, if there are farmland and lakes nearby, and the plant mainly treats sewage in the form of discharge, the pollution can be imagined.

From an environmental point of view, what needs to be paid attention to in the process of producing silicon carbide.

1. Light pollution: The production process requires ignition operation, that is, the smelting furnace body is burned and smelted in the open air, and there is fire, if the bridge ruler is near the residential area, it will affect the daily rest of the residents. However, air pollution is the mainstay, as for how far the harm is, depending on the wind direction where the plant is located, such smelting projects are not allowed to be approved now, and they are national restricted projects.

2. Pollutants in the atmosphere: dust, smoke, carbon monoxide (a small amount), carbon dioxide (a large amount), impurities contained in the raw materials used, and may also contain sulfur dioxide, nitrogen oxides, etc. 3. Water pollution:

The main reason is that the salt content is high, and if there are farmland and lakes nearby, and the plant mainly treats sewage in the form of discharge, the pollution can be imagined.

In order to prevent the white reed on the product from being used as a pile and the internal black heart, it should be ensured that there is enough flame channel when loading the bricks, and avoid firing under a strong reducing atmosphere. When the partial pressure of oxygen in the kiln is too high, the SiC on the surface of the brick will be seriously oxidized during the firing process, forming a glaze layer with impurity phase in imitation ridges, which seriously affects the appearance and high-temperature performance of the material.

The standard method for industrial production of silicon carbide is the reaction of silica with coke to produce silicon carbide, also known as the Acheson method.

The reaction is almost identical to that used to prepare crude silicon, and controlling the amount of coke added is key. If too much coke is added, it will contain more silicon carbide impurities, control the addition of coke, use the melting point of silicon is lower than that of silicon carbide, and release coarse silicon from the bottom of the furnace below 1800 degrees.

However, this crude silicon will still contain silicon carbide impurities, and the content is generally less than 5%.

The concentration of concentrated sulfuric acid and nitric acid is low, the effect is not good, and the high concentration and high temperature reaction are 95%, and the flotation is not good.

I can design a carbon removal method for you. 15237105015 Zhengzhou

Pickling, impurity removal and carbon removal of silicon carbide special cutting material, silicon carbide powder contains free carbon, carbon will have a certain impact on the cutting effect in the process of crystalline silicon wafer cutting, by adding chemical reagents to make the free carbon in the slurry float on the surface of the slurry, and the floating free carbon is removed by the automatic carbon machine.