Silicon Tetrachloride Distillation Process-manufacture,factory,supplier from China

Distillation is the use of SiCl4, and the difference between the relative volatility of impurities components, through several partial gasification and partial condensation process, to achieve the separation of mixed liquid, so as to obtain high purity silicon tetrachloride products.

In silicon tetrachloride purification, boron is the most difficult impurity to remove. Researchers have proposed compound method to remove boron from silicon tetrachloride, which has achieved satisfactory results and has been widely used in industrial production.

In recent years, China's polysilicon production has shown geometric development, but the disposal of polysilicon by-product silicon tetrachloride has become a difficult to step over the development of polysilicon industry "sill", let the silicon industry wear the hat of high pollution.

The basic principle of solid adsorption is adsorption separation based on the different polarity of chemical bonds of each component in a compound. Silicon tetrachloride is a symmetric molecule with no dipole moment. In contrast, the contained impurities such as BCl3, AlCl3, FeCl3, PCl3, etc. are asymmetric molecules with considerable dipole moments, which strongly tend to form additive chemical bonds and are easily adsorbed by the adsorbent.

High temperature hydrogenation of silicon tetrachloride is an important method to treat silicon tetrachloride as a by-product of polysilicon. High temperature hydrogenation is silicon tetrachloride and hydrogen as raw materials, heated by 1200 ~ 1250℃ graphite heater, thermal reduction reaction to produce  trichlorosilane. The advantages of the process are that the whole system is closed circulation, suitable for continuous and stable operation; Trichlorosilane products of high purity, need to distillation links less.

Silicon tetrachloride is an important chemical raw material, it is widely used to produce high-purity silicon, silane, silicone ester, silicone oil, silica gel and other products, widely used in ink, paint, resin, rubber, medicine, grease and other fields; Silicon tetrachloride can also be used to manufacture optical fiber, polysilicon, silicon dioxide, etc., in communications, photovoltaic power generation, optical instruments and other fields of application; In addition, silicon tetrachloride can also be used in the military field, metallurgy, casting and other fields.

Silicon tetrachloride which chemical formula is SiCl4 is an inorganic compound, because silicon chloride only exists in the form of SiCl4, silicon tetrachloride is also directly called silicon chloride. The appearance of this product is light yellow liquid, and the appearance of high-purity silicon tetrachloride is colorless and transparent liquid, volatile, with special odor, toxicity and corrosion. Silicon tetrachloride can be miscible with benzene, chloroform, ether, carbon tetrachloride and other organic solvents. It can be hydrolyzed in humid air and react violently with water.

The main by-product of trichlorosilane, silicon tetrachloride, is also the main raw material for the manufacture of silicone, its finished products are silicone ester, silicone oil, high temperature insulating paint, silicone resin, silicone rubber and heat resistant cushion lining materials. High purity silicon tetrachloride is also an important raw material for manufacturing high purity silicon dioxide, inorganic silicon compounds, quartz fibers and optical fibers.

The mixture of trichlorosilane and polysilicon, which is a by-product of the recombination from the bottom of the distillation column in the production of trichlorosilane and polysilicon, was used as raw material to prepare silica by gas phase hydrolysis. The effects of gasification temperature, flow rate and flow ratio of water vapor and chlorosilane mixture on physicochemical properties of the products were investigated.

A high purity trichlorosilane differential pressure coupled distillation process, using the high pressure tower top steam as the heat source of the low pressure tower reboiler, realized the energy integration and process optimization. Chemical simulation software PRO/Ⅱ8.1 was used to simulate the design parameters of two columns of high purity trichlorosilane differential pressure coupled distillation process and three columns of high purity trichlorosilane differential pressure coupled distillation process.

Silicon tetrachloride is mainly used in the manufacture of silicone esters, gaseous silica, silicone monomer, silicone oil, high temperature insulating paint, silicone resin, silicone rubber and so on. High-purity silicon tetrachloride is the main raw material for manufacturing fiber prefabricated rod, and the quality of fiber prefabricated rod directly determines the fiber performance. Therefore, high-purity silicon tetrachloride is the core raw material of fiber industry.

Silicon tetrachloride is an important raw material and intermediate product in the process of organic silicon synthesis and polysilicon production. Under different environmental conditions, silicon tetrachloride can react with a variety of substances to produce new substances.

SiCl4 is one of the most important inorganic silicon compounds, is a colorless, transparent, flowing smoke liquid, with suffocating odor, soluble in benzene, ether, chloroform and other most organic solvents. Silicon tetrachloride is a volatile liquid with strong asphyxiating odor. It can be used as raw materials for the production of gaseous silica, high purity silicon and organosilicide. The upstream of the silicon tetrachloride industry chain is the raw material market, mainly silicon powder, ferrosilicon, hydrogen chloride, etc.

Chlorine hydrogenation technology is to add HCl on the basis of low temperature hydrogenation technology to further reduce the reaction temperature and increase the yield of trichlorosilane. Chlorine hydrogenation reaction principle is as follows: 2SiCl4(g)+H2(g)+HCl(g)+Si(s)=3SiHCl3(g). Hydrogen plasma is generated by hydrogen discharge, which is passed into the reactor to react with silicon tetrachloride gas. Since hydrogen is dissociated into hydrogen atoms, the reactivity is greatly increased and it can easily react with silicon tetrachloride to form trichlorosilane.

The principle is to reduce high purity trichlorosilane with high purity hydrogen on the high purity silicon core at about 1100℃ to generate polycrystalline silicon deposited on the silicon core. On the basis of the traditional Siemens process, the improved Siemens process is equipped with a supporting process of energy saving, consumption reduction, recycling and utilization of a large amount of H2, HCI, SiCI4 and other by-products and a large amount of by-production heat energy.

Devices that use tail gas to recover cyclohexylamine are characterized in that they include: spray tower, circulating pump, condenser, defogger, photooxygen catalytic oxidizer, ozone treatment device, blower, chimney. Described in the circulating pump and spray the bottom connection, as described in the other side of the circulating pump are connected to the condenser, the condenser and the upper spray tower connection, described in the spray tower are connected to the top of demister, described in the mist bottom and photocatalytic oxidation, photocatalytic oxidation is described, ozone

The production process of trichlorosilane is mostly prepared by reaction of gold-grade silicon metal powder and hydrogen chloride gas in a fluidized bed reactor. Generally using gold grade metal silicon powder, hydrogen chloride gas by the combustion reaction of chlorine and hydrogen gas. Reaction temperature is 300-400 degrees, most of the pressure using micro positive pressure operation.

The invention relates to a refining method of dicyclohexylamine, belonging to the technical field of organic chemistry.

Dicyclohexylamine has the chemical properties of a secondary amine. It has a strong base and can form salts with various acids. Acylation may occur. In terms of solubility, dicyclohexylamine is slightly soluble in cold water but almost insoluble in hot water. Dry powder, carbon dioxide, soluble foam and sand are used to extinguish the fire.

Trichlorosilane (TCS or SiHCl3) is generated as follows within a high temperature, pressurized reactor: Si + 3 HCl ➡ SiHCl3 + H2 ，Si + 3 SiCl4 +2 H2 ➡ 4 SiHCl3 .The TCS is then sent to the CVD (Chemical Vapor Desposition) reactor. In the Siemens process, high-purity silicon "starter" rods or hairpins are exposed to trichlorosilane at 1150 °C in the CVD reactor.

It is obtained by catalytic hydrogenation of aniline and can be divided into atmospheric pressure method and pressure method. In addition, cyclohexamine can be prepared by catalytic ammonolysis of cyclohexane or cyclohexanol, reduction of nitrocyclohexane, and catalytic ammonolysis of cyclohexanone in the presence of hydrogen.The refining process often contains impurities such as aniline and water.

At present, there are two main synthesis methods of trichlorosilane: one is the traditional synthesis method, that is the silicon chloride method. The other is hydrolyzation of tetrachloride. At present, the mainstream method of polysilicon production is the modified Siemens method, using trichlorosilane reduction method. In recent years, with the continuous decline of polysilicon price, polysilicon production enterprises pay more and more attention to the control of production cost.

The process relates to a tail gas refining method, in particular to the hydrogenation of aniline to prepare cyclohexylamine and the deamination of dicyclohexylamine tail gas to refine hydrogen.

Nitrocyclohexane reduction method: This method takes nitrocyclohexane and hydrogen as raw materials, using reducing agent to generate cyclohexylamine, because nitrocyclohexane raw materials are difficult to obtain, this method is basically eliminated. Moreover, the process has some defects, such as low one-way conversion of aniline and poor selectivity of dicyclohexylamine.