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Method for producing sodium hydrogen sulfate and/or hydrate thereof by utilizing side product waste acid residue generated in production of chromic anhydride through sulfuric acid method

A technology of sodium bisulfate and chromic anhydride, which is applied in the field of producing sodium bisulfate and/or its hydrate, and can solve the problems of unfavorable production of high-quality basic chromium sulfate tanning agent, high sodium sulfate content, and environmental pollution

Active Publication Date: 2013-01-09
SICHUAN YINHE CHEM
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0005] (2) Chromium and acid in the waste acid mud are recovered for the production of basic chromium sulfate, but the content of sodium sulfate and iron content in the waste acid mud is relatively high, so it is not conducive to the production of high-quality basic chromium sulfate salt tanning agent
[0006] (3) The above two methods (1) and (2) have been popularized for many years, and the waste acid mud of most chromium salt factories has been utilized to varying degrees, but there are still a few chromium salt factories, especially the small ones that buy red alum sodium to make chromic anhydride The by-product waste acid sludge has not been effectively utilized, but is discharged directly or indirectly, wasting resources and polluting the environment

Method used

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  • Method for producing sodium hydrogen sulfate and/or hydrate thereof by utilizing side product waste acid residue generated in production of chromic anhydride through sulfuric acid method

Examples

Experimental program
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Effect test

Embodiment 1

[0068]Get sulfuric acid method to prepare 500kg of chromium-containing molten waste acid mud of chromic anhydride by-product, add yuanming powder 25kg wherein, record afterwards that hydrogen ion / sulfate ion mol ratio is 1:1 in the mixture gained, and wherein hexavalent chromium is with Na 2 Cr 2 o 7 .2H 2 O content is 1.5wt%. The mixture was warmed to 450 °C and then maintained at this temperature for 120 min. Add condensed water to dilute afterwards, be mixed with the concentration that is 25 DEG B , add sodium sulfate 11.25kg as precipitating agent afterward, stir 80min, precipitation occurs in the feed liquid. The obtained feed liquid was first coarsely filtered twice, and then finely filtered once, and the filtrate obtained by the fine filtration was left to stand for 8hr, and it was found that sedimentation occurred in the filtrate, and the sediment was filtered out. The filtrate obtained by filtering out the sediment is evaporated and concentrated to 55 ° of B é in...

Embodiment 2

[0071] Get sulfuric acid method to prepare 500kg of chromium-containing molten waste acid mud of chromic anhydride by-product, add yuanming powder 25kg wherein, record afterwards that hydrogen ion / sulfate ion mol ratio is 1:1 in the mixture gained, and wherein hexavalent chromium is with Na 2 Cr 2 o 7 .2H 2 O content is 1.5wt%. The mixture was warmed to 190 °C and then maintained at this temperature for 220 min. Add condensed water to dilute afterwards, be mixed with the concentration that is 25 DEG B , add sodium sulfate 11.25kg as precipitating agent afterward, stir 80min, precipitation occurs in the feed liquid. The obtained feed liquid was first coarsely filtered twice, and then finely filtered once, and the filtrate obtained by the fine filtration was left to stand for 8hr, and it was found that sedimentation occurred in the filtrate, and the sediment was filtered out. The filtrate obtained by filtering out the sediment is evaporated and concentrated to 55 ° of B é i...

Embodiment 3

[0074] Get 1000kg of chromium-containing molten waste acid sludge prepared by sulfuric acid method as a by-product of chromic anhydride, add concentrated sulfuric acid 10kg thereto, and record the hydrogen ion / sulfate ion mol ratio in the resulting mixture afterwards as 1:1, and wherein the hexavalent chromium is replaced by Na 2 Cr 2 o 7 .2H 2 O meter content is 3.5wt%, adds the sodium thiosulfate 2.4kg as reducing agent, obtains mixture. The resulting mixture was warmed to 550 °C and then maintained at this temperature for 80 min. Afterwards, add condensed water to dilute to prepare a concentration of 45°Bé, then add 52.5kg of sodium sulfate as a precipitating agent, stir for 90min, and precipitation occurs in the feed liquid. The obtained feed liquid was first coarsely filtered twice, and then finely filtered once, and the filtrate obtained by the fine filtration was left to stand for 8hr, and it was found that sedimentation occurred in the filtrate, and the sediment was...

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Abstract

The invention relates to a method for producing sodium hydrogen sulfate and / or hydrate thereof. The method comprises the following steps: (a), waste acid residue with the molar ratio of 0.9:1-1.1:1 of hydrogen ion and sulfate radical ion is provided; (b), the waste acid residue is diluted, precipitator for precipitating trivalent chromium ion is added to the diluted waste acid residue to form precipitation; (c), the precipitation generated in the step (b) is filtered out, filtrate containing sodium hydrogen sulfate is obtained, the filtrate is stilled for 2-80 hours, and the precipitation generated in the stilling process is filtered out; and (d), the stilled filtrate obtained in the step (c) after the precipitation is filtered out is crystallized, and the sodium hydrogen sulfate and / or the hydrate thereof are / is obtained. Through the method, the sodium hydrogen sulfate, sulfuric acid and sodium sulfate in the waste acid residue can be recovered, the total content of chromium in the prepared sodium hydrogen sulfate and / or the hydrate is low, and is generally lower than or equal to 10 ppm. Besides, the method is simple in technique and easy for gaining raw material, and is suitable for industrial production.

Description

technical field [0001] The invention relates to a method for producing sodium bisulfate and / or its hydrate by using waste acid mud, a by-product of producing chromic anhydride by a sulfuric acid process. Background technique [0002] Chromic anhydride production in my country mostly adopts the sulfuric acid production process. The raw materials used in this process are sodium red alum (crystal or concentrated solution) and concentrated sulfuric acid (or oleum), which react at a high temperature of about 200 ° C. The resulting product is chromic anhydride, and the by-product is molten liquid containing hexavalent chromium. The liquid contains a large amount of strong acidic substances, which is similar to mud, so it is commonly called waste acid mud. [0003] The waste acid sludge produced by chromic anhydride contains a large amount of sulfuric acid and sodium sulfate. At present, the treatment methods of by-product waste acid sludge in my country's chromium salt factories...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C01D5/02
Inventor 李先荣马顺友白礼太胡义华
Owner SICHUAN YINHE CHEM
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