The pure bismuth trioxide (bismuth oxide nanopowder) has α type, β type and δ type. α type is yellow monoclinic crystals, relative density 8.9, melting point 825 ℃, soluble in acid, insoluble in water and alkali. β type is a bright yellow to orange, tetragonal crystal system, relative density 8.55, melting point 860 ℃, soluble in acid but insoluble in water. Easily reduced to metallic bismuth by hydrogen, hydrocarbons, etc. δ-Bi2O3 is a special material with a cubic fluorite mineral structure. 1/4 of the oxygen ion position in its crystal lattice is vacant, so it has a very high oxygen ion conductivity. The main application objects of bismuth oxide are electronic ceramic powder materials, electrolyte materials, photoelectric materials, high-temperature superconducting materials, and catalysts. As an important additive in electronic ceramic powder materials, bismuth oxide is generally required to be above 99.15% purity. The main application objects are zinc oxide varistors, ceramic capacitors, and ferrite magnetic materials.
To the bismuth nitrate solution (80-90°C), an aqueous sodium hydroxide solution containing no carbon dioxide was added dropwise and mixed. The solution remains alkaline during the precipitation process, and a white, volume-swelling bismuth oxide hydrate Bi(OH)3 precipitates. This solution is heated and stirred for a short time to be dehydrated into yellow bismuth trioxide. After washing with water decantation, filtering and drying, the finished bismuth oxide product is obtained.
Under a nitrogen atmosphere, a 0.1 mol/L bismuth nitrate solution dissolved in 1 mol/L nitric acid (at 80 to 90° C.), a 1.5 mol/L sodium hydroxide aqueous solution without carbon dioxide was added dropwise to mix them. The solution remains alkaline during precipitation. Although a white, volume-expanded bismuth oxide hydrate Bi(OH)3 precipitates, it is dehydrated and turned into light yellow bismuth trioxide after being stirred in a hot solution. Decant wash 15 times with water without air and carbon dioxide, filter and dry.
After the metal bismuth is put into the graphite crucible and melted, an arc is formed between the graphite electrode and the metal surface to heat and oxidize under the oxygen flow. To ensure an adequate supply of oxygen, the crucible should be placed in a large container, and oxygen should be continuously supplied. The reaction temperature is 750-800°C, and β-bismuth trioxide with a purity of 99.8% or more is quickly generated. After the product is quenched in water or on a cold metal plate, a high-temperature phase β-type product can be obtained.
TRUNNANO (aka. Luoyang Tongrun Nano Technology Co. Ltd.) is a trusted global chemical material supplier & manufacturer with over 12 years’ experience in providing super high quality chemicals and Nano materials. The Bi2O3 powder produced by our company has high purity, fine particle size and impurity content. Lower, please contact us if necessary.
