Main applications of barium metaborate

Barium metaborate is also known as barium borate. White powder. Molecular weight 349.07. Dissolve in water. Functional pigments. It can enhance the anti-

mildew, anti-rust, fire and anti-pulverization properties of the coating. It is prepared by adding barium sulfide and borax aqueous solution into the autoclave,

adding a small amount of sodium silicate and heating at 125 ~ 140℃. At present, according to the data of different manufacturers, the particle size of barium

metaborate commodity generally fluctuates in 0.35 ~ 35μm, the average particle size is about 8μm, and the effective particle size is only 3μm; The existing barium metaborate has the disadvantages of moisture absorption, caking, high water solubility, poor compatibility in various resins and poor firmness in paint film, so it must be modified with amorphous hydrated silica. At present, the existing method of preparing barium metaborate is to melt barium salt (barium sulfide, barium hydroxide, barium carbonate, barium nitrate) and borate salt (boric acid, borax, etc.), or precipitate with its aqueous solution.

The main specific preparation methods are: 1) borax barium sulfide method: The mixture of barite and pulverized coal was roasted and leach with hot water in the extracter to obtain the barium sulfide liquid, and then the borax aqueous solution and sodium silicate aqueous solution were separately added to the reactor. After adding the three kinds of materials, the reactor was sealed, the temperature was raised to 110±5℃, the reaction was stirred for 2h, and the cooling was reduced to 70 ~ 80℃. After the precipitation was centrifuged, washed, dried and crushed, the reactor was cooled to 70 ~ 80℃. The finished barium metaborate is prepared. Disadvantages of this process: complex process, high requirements for equipment, harsh reaction conditions, high energy consumption, pollution to the environment. 2) Barium metaborate powder was prepared by liquid phase synthesis using barium hydroxide, boric acid and hydrogen peroxide as raw materials by Weimin of Fujian Institute of Material Structure, Chinese Academy of Sciences. This process requires centrifugal separation, vacuum drying, and is not suitable for large-scale production. 3) Zhou Youfu et al., Fujian Institute of Material Structure, Chinese Academy of Sciences, obtained barium metaborate powder by using inorganic salt and boric acid aqueous solution as raw materials and organic amine as precipitating agent. The powder was precipitated, filtered, dried, and calcinated at 650 ~ 850℃. This process is also liquid phase synthesis, but it needs to add precipitant, need to pump filtration, washing and other processes, and can not achieve all raw materials into products, easy to cause environmental pollution.

Apply

Barium metaborate is a kind of white functional pigment, which has anti-rust, anti-mildew, anti-pollution, anti-powder, prevent discoloration, flame retardant and other functions in the paint, is a multi-functional non-toxic anti-rust pigment, used in the manufacture of primer and topcoat anti-rust coatings. Barium metaborate can also be used in ceramics, paper, rubber and plastics industries. Barium metaborate exists in two polyforms: high temperature phase (α‑BaB2O4) and low temperature phase (β‑BaB2O4). Low temperature phase barium metaborate single crystal (β-BAB2O4) is a nonlinear optical crystal with comprehensive excellent performance, with a wide transmittance band (190nm ~ 3500nm) and phase matching range (409.6nm ~ 3500nm), large nonlinear optical coefficient, high light damage threshold, wide temperature band and superior optical uniformity. This provides practical possibilities for a variety of nonlinear optical applications. At present, low temperature phase barium metaborate single crystal (β-BAB2O4) is mainly used in: (1) Nd: YAG and Nd: YLF laser 2, 3, 4, 5 harmonic generation; (2)Frequency doubling, frequency tripling and frequency mixing of dye lasers; (3) The generation of 2, 3, 4 and 5 harmonics of titanium gem and amethyst laser; (4)can be used in the development of a variety of advanced laser technologies such as all-solid state, wide band modulation laser, ultra-short pulse laser, and DUV laser; (5) Optical parametric amplification (OPA) and optical parametric oscillation (OPO), etc. For example, the preparation of low-temperature phase barium metaborate single crystal film includes the following specific steps: in the platinum crucible, a mixture of Li2CO3 and Al2O3 with porosity is placed; The double-sided polished α-BBO wafer is placed or suspended on the platinum wire, and the crucible cover is covered with Li2CO3 and Al2O3 mixed powder and thermocouple, and the top of the crucible is sealed with platinum cover, and placed in the resistance furnace; The resistance furnace is heated to 700~1000℃, and the constant temperature is 2~100 hours, Li2O diffuses to α-BBO wafer, and α-BBO wafer solid phase reaction occurs, so that the α-BBO wafer surface phase transition, forming β-BBO single crystal film. The method can grow the required micrometer β-BBO single crystal film on the α-BBO substrate, which not only saves materials, but also can be mass-produced, and has important significance for the development of laser technology and integrated optics.

preparation

Method 1: A preparation method of barium metaborate nanopowder, the steps are as follows:

A. Weigh barium hydroxide and boric acid with A molar ratio of 1∶2, mix them well at room temperature, grind them until they change from solid to wet, and then from wet to viscous, and then continue grinding for 1h;

B. The product obtained in the above step is dried in the air atmosphere at room temperature, and the product Ba[B(OH)4]2 is obtained. It is compared with the

JCPDS standard card, and the crystal shape is consistent with the JCPDS standard card 48‑0941.

Method 2: Barium hydroxide was used to react with boric acid and hydrogen peroxide. The product is aged, washed, separated, dried and roasted to obtain nano-scale β-BaB2O4 powder, the reaction formula is as follows:

The specific preparation steps are as follows:

(1) The quantitative Ba(OH)2·8H2O was heated and dissolved in the quantitative distilled water with a concentration of 0.3mol/L-0.5mol/L, and then filtered hot

after dissolution;

(2) The quantitative H3BO3 was heated and dissolved in the quantitative distilled water with a concentration of 0.7mol/L-1.0mol/L. After slightly cooling, an

appropriate amount of 30% hydrogen peroxide aqueous solution was added, and H3BO3∶ 30% H2O2 = 1mol∶250ml-500ml;

(3) The spray (2) was added to the fully stirred (1), the reaction temperature was 30℃-60℃, the PH of the reaction system was 6-12, H3BO3∶Ba(OH)·8H2O =

2∶1-1.10(mol);

(4) After the reaction is completed, it is left to age for 30 minutes –62 hours, then centrifuged, and washed with distilled water or anhydrous ethanol several

times;

(5) After vacuum drying at 100-120℃, it is placed at 500℃-600℃ for 0.5-3h sintering.