Environment coordination type preparation method of nano titanium dioxide powder

Abstract

The invention discloses an environment coordination type preparation method of nano titanium dioxide powder, which comprises the steps of: by using green resource water as a single solvent, one of tetrabutyl titanate, titanium dioxide, titanyl sulfate, metatitanic acid, titanium sulfate and titanium tetrachloride as a titanium source, ammonia water or urea as a neutralizing agent, and ammonium nitrate as a combustion improver, introducing the ammonium nitrate by adopting the ammonia water and nitric acid or singly adding the ammonium nitrate, using lactic acid as a stabilizing agent, a chelating agent, a swelling agent and a pore-forming agent, preparing sol at room temperature by adopting a water-based sol-gel method, regulating the pH value by the sol, obtaining cream yellow opaque gel after the solvent is removed, spontaneously igniting, swelling and pore-forming the gel to obtain a nano pyrophorus, and thermally treating the pyrophorus for 0.5-1h at the temperature of 500-800 DEG C to prepare the nano titanium dioxide powder with different crystal phase structures. The prepared nano titanium dioxide powder has the advantages of no agglomeration, porous nano thin layer, uniform pore distribution, uniformity in pores and larger specific surface area.

Description

technical field [0001] The invention relates to a technology for preparing nano titanium dioxide powder, in particular to a technology for preparing titanium dioxide non-agglomerated nano powder by a water-based sol-gel method. It belongs to the field of functional materials and the production of nano-powders with green and environment-friendly technology. Background technique [0002] Due to its excellent physical, chemical, and dielectric properties, titanium dioxide is widely used in many fields such as chemical industry, materials, metallurgy, ceramics, and electronics. Its consumption is increasing year by year, and it has become one of the indicators for measuring a country's industrialization. However, since the application of titanium dioxide to the present, the industrial production of its powder mainly adopts the traditional solid-phase method, which includes the sulfuric acid method and the chloride method, and follows the grinding principle of the physical method...

AI Technical Summary

Problems solved by technology

However, since the application of titanium dioxide to the present, the industrial production of its powder mainly adopts the traditional solid-phase method, which includes the sulfuric acid method and the chloride method, and follows the grinding principle of the physical method. Poor uniformity, irregular shape, serious powder agglomeration, small specific surface area, unstable product quality, etc., only micron and submicron particle powder can be obtained, which greatly limits its application range

However, the sol-gel method is a preparation technology that is difficult to be practical after all. Its fatal disadvantages are: a large number of organic solvents and raw materials are used, the cost is expensive, the pollution is high, the stability is poor, and the powder is easy to agglomerate, difficult to operate, and repeated. Poor sex and so on, it has been limited to scientific research since its birth, and it is difficult to embark on industrialization

However, the sol-gel method is still a cornerstone for exploring new macroscopic powder preparation technology.

[0006] (2) The use of hydrothermal method to prepare titanium dioxide nanopowder has the advantages of high purity, good dispersibility, regular shape, no need for calcination, green water-based reaction, etc., but its high temperature and high pressure reaction conditions are harsh on equipment. The existence of mineralizers requires a corrosion-resistant lining, which is technically difficult and has a poor safety factor, resulting in a high overall cost. At the same time, it is difficult to prepare titanium dioxide thin film materials in large areas by this method, and the application range has certain limitations.

[0007] (3) The technology of preparing titanium dioxide powder by precipitation method has the advantages of simple process conditions, short process and low cost, making it quite promising for industrialization, but this process still has certain limitations in the preparation of nano-powder , powder particles are not easy to control, easy to agglomerate, small specific surface area, etc., it is difficult to achieve the purpose of producing high-quality powder

However, the existing pore-making technology has its fatal shortcomings: the powder is rough, the pore-forming agent and the powder are difficult to mix uniformly, there are many processes, the equipment is cumbersome, and the porosity is difficult to control, etc.

However, such a high-end preparation technology has extremely stringent requirements on equipment, processes, and raw materials, leaving macroscopic industrial production beyond the reach, resulting in numerous high-efficiency scientific research results that can only be limited to reports

[0010] The template method and powder directional growth technology are both for the purpose of pursuing materials with regular shape, nanometerization, and super large specific surface area. The effect of preparing powder is extremely ideal, but like thin film preparation technology, it is also a high-end technology. Its disadvantages: poor repeatability, high cost, complex equipment, difficult operation, etc., are difficult to meet industrial standards

The selection of water-based chelating agents is extremely harsh, because water is a highly polar substance, and most organic chelating agents are insoluble in water, or it is difficult to effectively complete the complexation of metal ions in strong polar solvents. or the chelating agent is expensive and impractical; although the found citrate method can effectively complex metal ions under aqueous conditions, the powder prepared by the process is rough and easy to agglomerate, and the effect is not the same as that of traditional Alcohol-based sol-gel method is far from practical value

In addition, the titanium sources for the preparation of titanium dioxide nanopowders are mainly titanium dioxide, titanyl sulfate, titanium chloride, tetrabutyl titanate, metatitanic acid, etc. Although the prices are in balance, they are either insoluble in water or instant when in contact with water. Rapid hydrolysis to generate titanium hydroxide, which is then hydrolyzed to titanium dioxide, making it difficult to prepare sols

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