Classifications

• • C—CHEMISTRY; METALLURGY
  • C01—INORGANIC CHEMISTRY
  • C01B—NON-METALLIC ELEMENTS; COMPOUNDS THEREOF; METALLOIDS OR COMPOUNDS THEREOF NOT COVERED BY SUBCLASS C01C
  • C01B33/00—Silicon; Compounds thereof
  • C01B33/113—Silicon oxides; Hydrates thereof
  • C01B33/12—Silica; Hydrates thereof, e.g. lepidoic silicic acid

Definitions

• the present invention relates to a sponge silica and a preparation method thereof.
• Silica (Si0 2 ) is insoluble in water and acids, has stable chemical properties, high temperature resistance, good electrical insulation properties, and is mostly used for reinforcing fillers.
• the traditional silica production method uses a common precipitation method, in which silicic acid is used Sodium and hydrochloric acid undergo a neutralization reaction at a high temperature, and the spherical silica is obtained by aging, filtration, washing, and drying.
• the silica produced by this method has poor purity, small specific surface area, and large particles, so it cannot be satisfied as, for example, Requirements for reinforcing agents for rubber products.
• Another method for manufacturing silica is the gas phase method, which uses silicon tetrachloride as a raw material, and obtains spherical silica products through thermal cracking combustion decomposition, aggregation, deacidification and other processes.
• Gas phase method Can produce small particles of silica, but strict process requirements, high production costs, and large environmental pollution.
• Another object of the present invention is to provide a method for preparing sponge silica.
• Another object of the present invention is to provide a silicon dioxide with high purity, small particle size, and large specific surface area.
• a sponge-like silica having micropores and irregular shapes.
• a method for preparing sponge-like silica including
• step C> is treated with an inorganic acid, which is added in atomized form to obtain a suspension of silicon dioxide, 0> wash the silica suspension with water,
• Figure 1 shows the sponge-like silica of the present invention (under 1 million times electron microscope).
• Figure 2 shows the spherical silica (under 100,000 times electron microscope) produced by Bayer Company of Germany. Detailed description of the invention
• the present invention prepares a sponge-like silica.
• the silica particles are different from the silica produced by the traditional method. It can be seen from FIG. 1 that under a 1 million times electron microscope, The silica particles of the present invention are sponge-like, and it can be seen from FIG. 2 that the silica particles produced by the conventional method are spherical.
• a sponge-like silica has micropores and is irregular.
• a method for preparing a sponge-like silica includes
• the neutralization reaction is performed at normal temperature and pressure, and the reaction time is about 1.5 to 6 hours.
• the reaction can also be carried out under stirring first, and then left to stand The product to form a silica sol.
• the entire reaction time, including stirring and standing, is about 6-48 hours.
• the ratio of inorganic acid to sodium silicate is about 1.2 ⁇ 2.5: 1 ⁇ 1.5 (volume ratio).
• the generated silica sol is mixed with sodium silicate, and the ratio of the silica sol to sodium silicate is about 1 ⁇ 10: 5-20 (volume ratio), and the mixing is performed at normal temperature and pressure.
• step 8> The mixture obtained in step 8> is treated with an inorganic acid to form a suspension of silica.
• the ratio of the inorganic acid to the mixture is about 15-30: 60-300 (volume ratio).
• the acid treatment is carried out under stirring and atmospheric pressure.
• the processing temperature is about 35 to 100 'C, preferably about 40 to 80'C.
• the inorganic acid is added in the form of atomization, and the acid treatment time is about 40 to 120 minutes.
• the inorganic acid is the same or different.
• the inorganic acid concentration used may be the same or different from the inorganic acid concentration of step A>.
• the wet silica washed with water is dried. Drying can be performed by conventional drying methods, for example, spraying, centrifugation, pressure and other drying methods, preferably spray drying methods.
• the inorganic acid may be hydrochloric acid, sulfuric acid, phosphoric acid, nitric acid, or the like, preferably sulfuric acid.
• the concentration of the inorganic acid is about 5 ° to 60. Be, preferably 15. ⁇ 55. Be.
• the concentration of sodium silicate is about 5 ° ⁇ 40 ° Be.
• the stirring speed is about 15-500 rpm.
• the sponge silica of the present invention has the following indicators after analysis: silica (dry basis) 92 to 98.5% by weight
• the silica prepared by the method of the invention has excellent activity and adsorption rate, good dispersibility, large specific surface area, many internal pores, and has strong affinity with various rubbers.
• the silanol groups on its surface are The rubber has a cross-linking effect during the vulcanization process, and has a prominent reinforcing effect.
• the silica prepared by the method of the present invention is used as a tire reinforcing agent, filler, abrasion resistance agent, anti-aging agent, and can improve the tire Service life 6-8 times. Widely used in cable and wire sheath, optical fiber, paint, ink, paper, plastic, etc.
• sponge-like silica is used as a rubber reinforcing agent.
• Example 7 7 parts by volume of the aqueous solution was processed under normal pressure and stirring, the temperature was controlled at 70 ° C, the processing time was 2.5 hours, the stirring speed was 350 rpm, the obtained silica suspension was washed with 40 times water, and then Spray drying at 500 -C, the product obtained is similar to Example 1.
• the specific surface area of the product is 300m 2 / g, containing 94% of silica, and its original particle size (without mechanical pulverization) is 99% below 10 microns. 60% below 5 microns, 23% below 1 micron, pH value 7.0, iron content 600ppm, moisture content 5%, DBP absorption value 2.0-3.0cm 3 / g.

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• Chemical & Material Sciences (AREA)
• Organic Chemistry (AREA)
• Inorganic Chemistry (AREA)
• Silicon Compounds (AREA)

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• 1996
  • 1996-05-14 CN CN96104972A patent/CN1048956C/zh not_active Expired - Lifetime
• 1997
  • 1997-05-14 WO PCT/CN1997/000047 patent/WO1997043213A1/zh not_active Ceased
  • 1997-05-14 AU AU27618/97A patent/AU725033B2/en not_active Expired
  • 1997-05-14 DE DE69727971T patent/DE69727971T2/de not_active Expired - Lifetime
  • 1997-05-14 EP EP97921583A patent/EP0959041B1/en not_active Expired - Lifetime

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