Method for recovering reagent grade sodium nitrate from waste liquid generated in citric acid bismuth production
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A technology of bismuth citrate and sodium nitrate, which is applied to the purification of alkali metal nitrates, etc., can solve the problems of polluting water sources, wasting resources, and destroying the ecological environment, and achieves the effects of simple operation, mild process conditions, and reduction of environmental pollution
Active Publication Date: 2011-04-20
GUANGDONG GUANGHUA SCI TECH +1
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If this waste liquid is discharged directly, it will not only pollute the water source, damage the ecological environment, but also cause a waste of resources
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Embodiment 1
[0023] (1) in the collected bismuth citrate production waste liquid, sampling detects sodium nitrate and sodium nitrite content as follows:
[0024] Sodium nitrate: 215g / L
[0025] Sodium nitrite: 0.06g / L
[0026] (2) Take 1500 liters of the above waste liquid, heat and concentrate in a 1000 liter stainless steel reaction pot until the specific gravity of the hot solution is 1.16-1.18 (about 800-900 liters left), and then add 110g of AR grade NH 4 NO 3 (excessive about 5.4%), stir to dissolve, then heat and keep slightly boiling and stir at a slow speed for 2 hours, so that the nitrite can be fully decomposed and removed;
[0027] (3) Dissolve the analytically pure Ca(OH) with an appropriate amount of pure water 2 Adjust it into an emulsion, slowly add it to the above-mentioned treated waste liquid with stirring until its pH value is 7-8, then heat and boil for 15 minutes, and filter while it is hot to obtain a clear liquid;
[0028] (4) Add AR grade anhydrous sodium carbo...
Embodiment 2
[0033] (1) in the collected bismuth citrate production waste liquid, sampling detects sodium nitrate and sodium nitrite content as follows:
[0034] Sodium nitrate: 207g / L
[0035] Sodium nitrite: 0.07g / L
[0036] (2) Take 1500 liters of the above waste liquid, heat and concentrate it in a 1000 liter stainless steel reaction pot until the specific gravity of the hot solution is 1.18-1.20 (about 800-900 liters left), and then add 130g AR grade NH 4 NO 3 (excessive about 6.8%), heated after stirring and dissolving, kept slightly boiling and stirred at a slow speed for 2.5 hours, so that the nitrite was fully decomposed and removed;
[0037] (3) Dissolve the analytically pure Ca(OH) with an appropriate amount of pure water 2 Adjust it into an emulsion, slowly add it to the above-mentioned treated waste liquid with stirring until its pH value is 7-8, then heat and boil for 20 minutes, and filter while it is hot to obtain a clear liquid;
[0038] (4) Add AR grade anhydrous sodi...
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Abstract
The invention provides a method for recovering reagent grade sodium nitrate from waste liquid generated in a production process of citric acid bismuth prepared by the reaction of nitric acid bismuth solution with citric acid and sodium carbonate solution. The method comprises the following steps: heating and concentrating the collected waste liquid until the proportion of the heat solution is 1.15-1.20; adding 5-8% of ammonium nitrate into the waste liquid, wherein the molar ratio of the ammonium nitrate is equal to that of the sodium nitrite in the waste liquid; heating to microboil to remove the impurities of nitrite; adding calcium hydroxide to remove a small amount of residual citric acid in the reaction; adding the sodium carbonate to regulate the pH value of the waste liquid; preserving the temperature to remove the heavy metal impurities and excessive calcium; regulating the pH value of the filtrate by nitric acid; and concentrating and crystallizing to obtain the reagent grade sodium nitrate. The method for recovering the sodium nitrate is simple in operation and moderate in process condition, can be used for effectively removing various purities in the waste liquid; the comprehensive recovery rate is up to 75-85%; and the obtained product conforms to the analytically pure standard of GB/T 636-1992 chemical reagent. In the invention, the waste liquid is comprehensively processed and utilized to recover the reagent grade sodium nitrate, thus achieving the purposes of saving the energy, reducing the emission, lowering the environment pollution and lowering the production cost.
Description
technical field [0001] The invention relates to a production method of sodium nitrate, in particular to a method for recovering reagent-grade sodium nitrate from bismuth citrate production waste liquid, and more specifically to a method prepared by reacting bismuth nitrate solution with citric acid and sodium carbonate solution. A method for recovering reagent-grade sodium nitrate from the waste liquid produced in the bismuth citrate production process. Background technique [0002] Sodium nitrate is a colorless transparent crystal, white granule or powder, odorless, slightly bitter taste, slightly hygroscopic in humid air, easily soluble in water, slightly soluble in ethanol, methanol and glycerin. The melting point of sodium nitrate is 306.8°C. When heated to 380°C, it decomposes into sodium nitrite and oxygen. Sodium nitrate is a strong oxidizing agent and an important chemical raw material and analytical reagent. It is mainly used in the manufacture of glass, dyes, medi...
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