First, antimony trioxide
Bismuth oxide of bismuth compounds is important for the chemical reagent, manufactured manufacturing bismuth salt formulation, synthetic inorganic, colored glass-ceramics, and paper manufacturing fire, electronic components, high refractive index glass and glass nuclear engineering, and for nuclear reactor fuel .
The production method of cerium oxide is either fire method or wet method, and all products can meet the quality requirements.
(1) Fire method
1. Process flow. Figure 1.
Figure 1 Process of producing cerium oxide by fire method
(2) Main technical conditions. The No. 1 fine enthalpy is melted and slowly added into a water quenching tank to be quenched into loose porous particles having a particle size of 5 mm or less.
Nitric acid dissolution: The volume of nitric acid is diluted twice with distilled water, and water quenching is added at normal temperature. The reaction is:
Bi+4HNO 3 =Bi(NO 3 ) 3 +NO+2H 2 O
In order to prevent a large amount of nitrogen oxides from escaping, water quenching should be added slowly. The solution after the reaction is a cerium nitrate solution.
Concentrated crystal: The concentration temperature is controlled at about 100 ° C, the volume of the solution is evaporated to 50% and the crystal is cooled. After 10 hours, 60% to 70% of the cerium nitrate contained in the solution is crystallized out; after the precipitated cerium nitrate crystal is separated, The mother liquor is concentrated again, the volume is doubled, and 20-30% of cerium nitrate crystals are obtained. The impurities are all left in the second mother liquor, and the second mother liquor is heated and treated with water to form a basic cerium nitrate precipitate. (OH) 2 NO 3 is filtered and then returned to dissolve with nitric acid: the precipitated cerium nitrate crystals are washed with a small amount of acid-containing water (H 2 O:HNO 3 =5:2), and air-dried at room temperature, which releases part of the nitrogen. Oxide tail gas.
Calcination: The temperature is controlled at about 600 ° C, and the burning time is 3 to 4 hours, at which time a large amount of nitrogen oxide gas escapes. The response is:
4Bi(NO 3 ) 2 =2Bi 2 O 3 +12NO 2 +3O 2
After calcination until nitrogen oxides escaped, the temperature was lowered, and the calcined cerium oxide was taken out and pulverized to a particle size of 60 mesh using a ceramic ball mill .
3. Main equipment. One muffle electric furnace; one porcelain ball mill.
(2) Wet method
1. Process flow. As shown in Figure 2.
Figure 2 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.
2. 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.
3. 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.
4. 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.
Second, bismuth oxychloride
Bismuth oxychloride is a hydrolysis product of antimony trichloride, which is mainly used in the plastics industry to make plastic products have a beautiful jewel. The dosage is generally bismuth oxychloride: the resin is 0.4% to 0.8%, and can be increased or decreased according to the variety requirements.
(1) Process flow. As shown in Figure 3, it includes processes such as dissolution, conversion hydrolysis, washing and drying, and drying.
Figure 3 bismuth oxychloride production process
(2) Main technical conditions. The water-quenched cerium particles are dissolved in a dilute nitric acid solution to form a cerium nitrate solution.
Salt conversion: The cerium nitrate solution was added to a saturated saline solution (density 1.2 g/cm 3 ), and stirred uniformly. If a white hydrolyzate was produced, it was slightly diluted with hydrochloric acid to dissolve.
Hydrolysis: The dilution water corresponding to 4 times the volume of the ruthenium chloride solution is heated to 95 ° C, and hydrochloric acid equivalent to 0.7% to 0.8% of the volume of the dilution water is added to the dilution solution, and the mash is poured under stirring, and then heat is used. The water was diluted to pH = 2.3, and after clarification, it was separated from the supernatant, and BiOCl was washed with distilled water to pH > 5.
Drying: BiOCl is dried at a constant temperature of 95 to 100 ° C, dried, and passed through 80 mesh.
(3) Major equipment. One stainless steel dissolution tank: one for the conversion of hard polyvinyl chloride plastics; one for the hydrolysis tank: one for the centrifuge.
(4) Product quality. The produced bismuth oxychloride component is (%): BiOCl > 98.5, H 2 O < 0.5, and acid insoluble matter is less than 0.1.
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