Some Overview Of White Carbon Black Production Process

     硅在自然界中主要以二氧化硅和硅酸盐的状态存在，一切植物皆含有少量的二氧化硅，动物体内的结缔组织中亦含有二氧化硅。硅在地壳中的含量是绝对丰富的，硅在地壳中的重量百分数为27.6%，仅次于氧（47.2%）为第二位。

Inorganic silicon compounds are fast growing products in inorganic chemicals in 80s, especially in recent years.

The patent abstracts of silicon compounds account for the absolute superiority in the inorganic chemistry category of patent index of Derent center.

It can be seen that inorganic silicon compounds are obviously competitive in many inorganic chemicals.

Throughout the world, new varieties of silicon compounds have not been increased in recent years, and the development of inorganic silicon compounds is more important.

For example, the oldest variety of silicon compounds, sodium silicate, is also developing towards high performance and high added value. In the US, Mobil has developed various specifications for ZSM zeolite, which can be applied to various catalytic processes in petrochemical industry.

Therefore, from the current development trend, inorganic silicon compounds will enter a large number of fields such as light industry, food, medicine, construction, electronics, metallurgy, machinery industry and so on.

China's silicon compound products are mainly developed after liberation. There are only dozens of varieties so far, so the gap is bigger.

China has high quality and abundant resources, which provides material basis for research and development of more silicon compounds.

In the past more than 10 years, the Ministry of chemical industry has not only received the attention of the Ministry of chemical industry, but also commissioned the scientific research units to publish the data of "silicon aluminum compounds".

It can be expected that the development of silicon compounds in China will grow faster and faster, and the gap between the developed countries and the world will be smaller and smaller.

White carbon black is an older variety of silicon compounds. In the middle of the 30s, Germany, Soviet Union, the United States and other countries began to develop, and by the end of 40s, it entered industrial production. In 80s, the total production capacity reached 70~80 tons / year.

China started in 60s, and there were two thousand ton plants in 80s. The total annual output is only 5000~6000 tons, and the varieties are few, the quality is poor, the energy consumption is high, and there is no serialization.

Therefore, the task of developing new products and developing applications is very arduous.

     1.物理化学性质

The appearance is white and highly dispersed amorphous powder or floc powder, and also processed into granules as commodities.

The specific gravity is 2.319 to 2.653 and the melting point is 1750 degrees.

Insoluble in water and most acids, it will become fine aggregates after absorbing moisture in air.

Soluble in caustic soda and hydrofluoric acid.

For other chemicals stable, high temperature, no decomposition, no burning.

It has high electrical insulation and porosity.

The inner surface area is large, and it has greater dispersion in raw rubber.

The surface modified hydrophobic silica can be easily dissolved in oil, and used as reinforcing filler for rubber and plastics, so that the mechanical strength and tear resistance index of the products will be significantly improved.

Because of the different manufacturing methods, the physical and chemical properties and microstructure of silica will be different, so its application and application results are different.

     2.用途

Silica has a wide range of uses and different products have different uses. Now it is summarized as follows: as a good reinforcing agent for synthetic rubber, its reinforcing property is only inferior to that of carbon black, and it is even better than carbon black after superfining and proper surface treatment.

Especially when making white, coloured and light colored rubber products.

Used as thickener or thickener, synthetic oil, varnish for blending, paint degustrant, thixotropic agent for encapsulating material of electronic component, precipitating agent for phosphor, color printing plate filler and casting release agent when fluorescent screen is applied.

The moisture and insulation properties of the resin can be improved by adding resin.

Filling in plastic products can increase skid resistance and oil repellency.

Filled with silicone resin, it can be made of plastics resistant to more than 200 degrees.

In the paper industry, it is used as a filler and filler for paper.

There are also carriers and dispersants used as pesticides and pesticides, anti caking agents, liquid adsorbents and lubricants.

     3.生产方法概述

The production methods of white carbon black, according to domestic and foreign data, are mainly two types of precipitation and gas phase methods.

Because the raw materials used in the precipitation method are cheap and easy to get, the production process and equipment are relatively simple, and the price of the products is low.

The following are the following methods:

Precipitation is also called wet process. The main raw materials are quartz sand, soda ash, industrial hydrochloric acid or sulfuric acid or nitric acid or carbon dioxide.

The technological route is generally: first, using oil or high quality coal to react the quartz sand with soda ash at high temperature to produce industrial water glass. The industrial water glass is formulated into a certain concentration of dilute solution with water, then certain acid is added under certain conditions to precipitate silica, then cleaned, filtered, dried (dried or sprayed), smashed, and made the product white carbon black.

Precipitation method also includes many different methods, such as acid method, sol method and carbonization method.

    (1)酸法

Generally speaking, the acid method is to react the soluble silicate with sulfuric acid or other acids. When the reaction liquid reaches a certain pH value, stop adding acid reaction, aging it, then filtrate it and rinse it repeatedly with water. After Na2SO4 is removed, the product is dried and crushed.

This is a better process, but the process is more complex than the acid method, and the condition control requirement is higher.

First, the reaction of hydrochloric acid and sodium silicate is used to form a certain concentration of dilute sol. Under the condition of micro heating and stirring, the sodium silicate solution is added to the prepared sol, and a certain amount of NaCl solution is added. The reaction reaches pH=7 ~ 8. The pH value is kept with the alkaline adjusting liquid, and then is heat-treated and aged, then rinsed and removed, and then filtered, dried and packed.

This is a better process, but the process is more complex than the acid method, and the condition control requirement is higher.

First, the reaction of hydrochloric acid and sodium silicate is used to form a certain concentration of dilute sol. Under the condition of micro heating and stirring, the sodium silicate solution is added to the prepared sol, and a certain amount of NaCl solution is added. The reaction reaches pH=7 ~ 8. The pH value is kept with the alkaline adjusting liquid, and then is heat-treated and aged, then rinsed and removed, and then filtered, dried and packed.

    (2)溶胶法

This is a better process, but the process is more complex than the acid method, and the condition control requirement is higher.

First, the reaction of hydrochloric acid and sodium silicate is used to form a certain concentration of dilute sol. Under the condition of micro heating and stirring, the sodium silicate solution is added to the prepared sol, and a certain amount of NaCl solution is added. The reaction reaches pH=7 ~ 8. The pH value is kept with the alkaline adjusting liquid, and then is heat-treated and aged, then rinsed and removed, and then filtered, dried and packed.

     (3)碳化法

The method uses carbon dioxide gas to carbonate through soluble silicate solution to produce precipitated SiO2 and sodium carbonate. After the reaction is finished, it is pre filtered, and the Na2CO3 in the product is removed by acidic water solution, then filtered, dried, crushed and packed.