Bismuth trioxide: What are its benefits?
There are three types of pure bismuth triooxide (bismuth dioxide): a, b and d. Yellow monoclinic crystals with relative density 8.9, melting temperature 825, are the -type. They can dissolve in acids, water, and alkali. Bright yellow to orange, Tetragonal Crystal System, relative density 8.55 and melting point 860 respectively, insoluble in acids but soluble in water. Hydrocarbons, hydrogen and other hydrocarbons can reduce the material to metallic bismuth. -Bi2O3 consists of a very special material that has a cubic fluorite crystal structure. Because 1/4 of its oxygen position in crystal lattice’s oxygen ion structure is empty, it exhibits very high oxygen conductivity. Electronic ceramic powder materials and electrolyte, photoelectric, high-temperature superconducting, materials, as well catalysts are the main applications of bismuth dioxide. A purity of at least 99.15% is required for bismuth dioxide as an essential additive to electronic ceramic powder materials. Principal applications are ceramic capacitors and zinc oxide varistors.
Chemical and Physical Properties of Bismuth Trioxide
Bismuth trioxide’s properties include monoclinic and yellow-colored powders as well as stable air stability. The melting point for bismuth is at approximately 825°C. It changes color to maroon upon heating and to yellow on cooling.
Synthesis of BismuthTrioxide
1. Dropwise add aqueous sodium chloride (8090) to the bismuth solution. Mix thoroughly. After precipitation, the solution will remain alkaline and precipitate as a white volume-swelling bismuth dioxide hydrate Bi(OH).3. To make yellow bismuth trioxide, heat the solution and stir it briefly. You will get the final bismuth dioxide after washing it with water, filtering it, drying and then cleaning.
2. Dropwise, mix a 1.5mol/L sodium chloride aqueous solution (without carbon dioxide) with a 0.1mol/L bismuth nuitrate solution. Mix them in 1mol/L NaOH at 80-90°C. After precipitation, the solution will remain alkaline. A white volume-expanded bismuth oxide hydrate Bi(OH),3 may precipitate. It is then dehydrated to yellow bismuth trioxide by heating a solution. Decant wash fifteen times using water without oxygen and carbon dioxide. Filter and dry.
3. Once the bismuth has been melted in the graphitecrucible, the oxygen flow creates an arc between the graphite and metal surfaces to heat up and oxidize. You should place the crucible in a large container. The oxygen must also be supplied continuously to keep it oxygen-rich. You can quickly generate -bismuth Trioxide at a temperature of 750800. The product can then be cooled in water and/or on a cold plate to form a high temperature phase b.
4. Slowly stir the excess sodium carbonate solution with Bi(NO3)35H2O acidic solutions (20g) and mix in 2mol/L HNO3. To precipitate Bi2O2CO3, filter the solution, wash it, and then dry. It can be placed in an aluminum container and heated at 650 K for approximately 1.5 hours to produce bBi2O3 substance.
5. Burn bismuth subnitrate at 400~500 to remove NO3- ions for about (3~4h): 2BiONO3=Bi2O3+NO+NO2+O2
Once the fire is out, it cools down and all become lemony yellow.
6. You can wash 16kg of 99.9% conductive bismuth surfaces with a little bit of dilute Nitric Acid. Next, you will need to use conductive waters to remove the surface nitric. After adding the 1:1 high-purity acid (35kg of nitric, with a relative densities of 1.42 + 20L conductive), continue reacting for 10 minutes. The filtrate should be cooled slightly. After that, it must be evaporated and concentrated to a relative density of 1.9. Make a solution of the obtained bismuth-nitrate. Stir it briefly, and then let it sit for at least 30 minutes.
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