Wet production of antimony trioxide
First, the process.
Figure 1.
Figure 1 Process for wet production of antimony oxide
Including dissolution, neutralization, drying and other processes to produce cerium oxide; the filtrate is converted and crystallized to produce sodium nitrate.
Second, the main technical conditions.
Water quenching and nitric acid dissolution are produced by the same method. Neutralization: The reaction of cerium nitrate with liquid base is as follows:
2Bi(NO 3 ) 3 +6NaOH=Bi 2 O 3 +6NaNO 3 +3H 2 O
The solid base was dissolved in distilled water to prepare a 30% NaOH solution, and after clarification, the suspended matter was removed, and the supernatant was taken for use. The supernatant is required to be clear and transparent and not stained. Then, the NaOH solution having a volume of 1.5 to 2.5 times that of the nitric acid solution is heated to about 95 ° C, and the saturated cerium nitrate solution is gradually injected into the heated NaOH solution, and the temperature is raised while stirring, so that the precipitate of cerium oxide formed is yellow. Note that it cannot be added too fast, too fast, it is easy to produce white barium hydroxide and basic barium nitrate precipitation.
When the saturated cerium nitrate solution is added in a volume of about one-half of the NaOH solution, although the NaOH concentration in the solution is still about 5 N at this time, it cannot be added, and a white flocculent cerium hydroxide colloid is formed. Stirring and holding for half an hour, the resulting cerium oxide changed from light yellow to clear yellow, then turned to dark yellow, and then remained dark yellow.
Filtration and washing: After neutralization, the heating and stirring are stopped, and the filtration is carried out, and the precipitate is a Bi 2 O 3 powder, which is washed with water several times until the washing water is neutral, and the dried cerium oxide powder (about 200 mesh) is a product.
Nitric acid conversion: In addition to NaNO 3 in the filtrate, NaOH is still present, and HNO 3 is slowly added to the filtrate to convert NaOH to NaNO 3 , and the reaction is:
When the solution is neutral, it means that the sodium hydroxide has been completely converted into a sodium nitrate solution, and then heated and concentrated to crystallize, and the by-product sodium nitrate is precipitated.
Third, the main equipment.
One stainless steel dissolution tank: one neutralization tank, one concentrated crystallizing tank, a jacketed enamel reaction kettle, mechanical stirring: one centrifuge; one oven.
Fourth, product quality.
When using water production up to industrial pure grade, having a composition of (%): Bi 2 O 3 > 98.5%, Fe <0.01, the alkali metal sulfate is less than 0.1, less than 0.1 Hydrochloric acid insoluble; when distilled water When produced, it can reach chemical grade, its composition is (%): Bi 2 O 3 is higher than 99.5, Fe<0.005, alkali metal sulfate is less than 0.03, and hydrochloric acid insoluble is less than 0.005.
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