Preparation Of Ultrafine Bi <sub> 2 </ Sub> O <sub> 3 </ Sub>

Owning two superiorities of bismuth reserve and bismuth output, our country plays a predominant role in the international bismuth market. Because the bismuth product structure is simple, so developing the bismuthic deep process product is necessary. Especially the good property Bi2O3 is still needed to be imported, so the research on the development of bismuth with higher-quality has much significance.Firstly, Bi2O3 was obtained in the groping experiments. The results indicated that the method of ammonia precipitation has advantages to get superfine Bi2O3 powder. This method has low expenses and simple process too. And so this method was determined for the preparation of super-fine Bi2O3.In the process of super-fine Bi2O3 preparation with ammonia precipitation, the influences of pH, Bi(NO3)3 and ammonia concentration, the ammonia adding rate, stirring speed, temperature were discussed in detail.The optimum technological conditions were obtained as follows: pH is 7.8, Bi(NO3)3 concentration is 0.25mol/L, ammonia concentration is 5%, the ammonia adding rate is 1.5mL/min, stirring speed is 800 r/min, drying temperature is 60 C, calcining temperature is 560C and the reaction time is 2 hours.Under the conditions, the Bi2O3 prepared has the appearance of cobblestone, crystal of a-style, particle size distribution of 0.1~0.9 urn and the mean size of 0.4 um.The influences of surfactants on the Bi2O3 were investigated.Through comparison, polyvinyl alcohol-124 and sodium oleate were selected as surfactants, and by controlling their concentrations for 4*103 mol/L and 0.8xl0'3 mol/L respectively, Bi2O3 with mean size of 0.2 \xm was obtained.The properties of wave absorption and catalyze of the Bi2O3 were preparatorily investigated. The research on wave absorption showed that electromagnetic wave about 10 GHz could be well absorbed, which meant the Bi2O3 had a good capacity of wave absorption and could beused in material manufacture for such field. The investigation of catalyze indicated that the Bi2O3 could oxidate sodium nitrite under the light, which deserved further research.