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Method for reclaiming calcium oxalate from sewage comprising oxalic acid

A technology for calcium oxalate and acidic wastewater, applied in the field of calcium oxalate recovery, can solve problems such as lead pollution, and achieve the effects of avoiding pollution, stabilizing chemical properties, and improving recovery rate

Inactive Publication Date: 2004-09-01
周建华
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  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

[0003] The object of the present invention is to provide a kind of milk of lime neutralization-the two-stage process of milk of calcium sulfate replacement reclaims the method for calcium oxalate from the oxalic acid-containing waste water that borneol production process produces, to overcome the lead pair that traditional lead sulfate method brings Disadvantages such as pollution caused by the environment

Method used

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  • Method for reclaiming calcium oxalate from sewage comprising oxalic acid
  • Method for reclaiming calcium oxalate from sewage comprising oxalic acid

Examples

Experimental program
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Effect test

Embodiment 1

[0011] First, put 5.1 cubic meters of waste water containing 209 g / L oxalic acid into a jacketed enamel reaction kettle, start stirring, then add lime milk to carry out neutralization reaction, control the reaction temperature at 80°C, and reach the oxalate content in the waste water When it is 22g / L, stop adding milk of lime, obtain part of calcium oxalate and wastewater to be treated, the main neutralization reaction is:

[0012]

[0013] According to the oxalate content in the waste water to be treated is 22g / L, then add calcium sulfate 346.8kg (according to CaSO 4 Dry weight 2 times of stoichiometric amount) emulsion, control reaction temperature is 95 ℃, obtain calcium oxalate and acid waste water, main displacement reaction is:

[0014]

[0015]

[0016]

[0017] Dry the reacted material through a centrifuge, and wash it twice with water at the same time, and the calcium oxalate after drying can reach the following indicators through analysis:...

Embodiment 2

[0025] 4.8 cubic meters of waste water containing oxalic acid, add milk of lime for neutralization reaction, control the reaction temperature at 85°C, until the content of oxalate in the waste water is 25g / L, then add calcium sulfate 371kg (CaSO 4 According to the emulsion of 2 times of the stoichiometric amount) of the dry weight, the temperature of the replacement reaction is controlled to be 95° C., and all the other are the same as in Example 1.

Embodiment 3

[0027] Control the neutralization reaction temperature to be 90°C, add calcium sulfate 400kg (according to CaSO 4 Dry weight more than 2 times of the emulsion of the stoichiometric amount), the control displacement reaction temperature is 98 ℃, and all the other are the same as embodiment 1.

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Abstract

The invention relates to a process for reclaiming valuable substance from waste water, in particular a process for reclaiming calcium oxalate from waste water containing oxalic acid, characterized in that the process comprises the two steps of lime cream neutralization and calcium sulfate substitution, wherein the step of lime cream neutralization comprises charging lime cream into waste water containing oxalic acid for neutralization reaction, controlling the reaction temperature to be 80-90 deg. C, when the content of oxalic acid roots in the waste water amounts to 22-25 g / L, ceasing the charging of lime cream, while the calcium sulfate substitution step comprises charging calcium sulfate cream exceeding stoichiometric calculation amount into the waste water to be processed for displacement reaction, controlling the reaction temperature to be 95-98 deg. C, thus obtaining calcium oxalate and acid wastewater.

Description

technical field [0001] The invention relates to a method for recovering valuable substances from waste water, in particular to a method for recovering calcium oxalate from waste water containing oxalic acid. Background technique [0002] In the process of producing borneol with oxalic acid as a catalyst, the recovery of oxalic acid has been perplexing various production companies. Over the years, various manufacturers have been using lead sulfate (P b SO 4 ) for the intermediate to carry out oxalic acid recovery, the biggest disadvantage of this method is that lead will inevitably enter the waste water, causing serious environmental pollution, and at the same time, as time goes on, the activity of lead sulfate gradually decreases, resulting in low yield, Production costs are too high. Contents of the invention [0003] The object of the present invention is to provide a kind of milk of lime neutralization-the two-stage process of milk of calcium sulfate replacement produ...

Claims

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Application Information

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IPC IPC(8): C07C51/487C07C55/07
Inventor 周建华
Owner 周建华
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