Washing method of oxalic acid precipitation

A technology of oxalic acid precipitation and washing method, applied in the direction of extraction water/sewage treatment, etc., can solve the problems of inability to recycle water resources, no recycling and utilization of water resources, high environmental protection costs, etc., and achieve low reagent costs, reduce wastewater treatment costs, split phase effect

Inactive Publication Date: 2011-10-26
CHINA MINMETALS BEIJING RES INST OF RE
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

The use of neutralization method cannot recycle water resources; the use of adsorption, electrolysis, reverse osmosis and other methods consumes a lot
High environmental costs due to absence of recoverable expensive heavy metals in such acidic wastewater
Therefore, the existing washing methods are all pure water washing and then directly lime neutralization and discharge, without recycling water resources

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0025] 1 ton of rare earth oxalic acid is precipitated and placed in the filter tank for continuous washing with water. The conventional washing process produces 10m 3 Washing waste water contains hydrochloric acid and oxalic acid. Mix 500L washing water with 500L organic phase N235-kerosene for extraction and separation, the concentration of N235 extractant is 1.5mol / L. All the acid goes into the organic phase, and 500L of pure water without other ions is obtained, which can be reused as recirculating washing water for precipitation. 500L of acid-containing organic phase was neutralized by 100L of 6mol / L NaOH solution according to O:A=5:1 to obtain saturated NaCl and sodium oxalate solution. The concentration of the salt solution is very high, which is convenient for concentration and crystallization, the discharge of waste water is reduced by more than 80%, and the organic phase can be recycled after being neutralized by NaOH. Due to washing water from 10m 3 Reduced to 50...

Embodiment 2

[0027] After 500Kg of cobalt nitrate oxalic acid is precipitated, the conventional method needs to be washed with water for 6 times, adding 1m of water each time 3 . The first washing water obtained from the first washing is 1m 3 with 10m 3 The organic phase N263-octanol is mixed for extraction and separation, and the concentration of N263 extractant is 0.1mol / L. The acid goes all into the organic phase, giving 1m 3 The pure water does not contain other ions and circulates for the second washing of the precipitation, and the washing is repeated 6 times in sequence. The acid-containing organic phase is neutralized with 5mol / L ammonia water according to O:A=1:1, and high-concentration ammonium nitrate and ammonium oxalate solutions are obtained after the ammonia water is recycled for many times. The concentration of the ammonium salt solution is very high, which is convenient for concentration and crystallization, the discharge of waste water is reduced by more than 80%, and...

Embodiment 3

[0029] After the red phosphor material yttrium europium chloride is precipitated by oxalic acid, a large amount of washing wastewater is generated in the precipitation washing process. The washing water contains hydrochloric acid and oxalic acid, and the pH is 1. will be 10m 3 Washing water and 1m 3The organic phase N235-kerosene is mixed for extraction and separation, and the concentration of N235 extractant is 1mol / L. The acid goes all into the organic phase, giving 10m 3 Pure water does not contain other ions and can be reused as washing water for precipitation. The acid-containing organic phase is neutralized with the aqueous solution containing MgO solids according to O:A=1:1, and the saturated magnesium chloride solution is obtained after constantly replenishing the consumed MgO solids. The concentration of the salt solution is very high, which is convenient for concentration and crystallization, the discharge of waste water is reduced by more than 90%, and the organi...

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Abstract

The invention provides a washing method of oxalic acid precipitation. The mechanism of the method comprises: acid in washing wastewater of the oxalic acid precipitation containing only inorganic acid and oxalic acid is extracted by amine extracting agent to enter organic phase to obtain purified water capable of washing the precipitation, and high concentration alkaline aqueous solution is used to directly neutralize the acid in the organic phase to make the organic phase to be reused. The method has the advantages of large treatment capacity of wastewater, fast reaction speed, rapid phasesplitting, low cost of reagents and small energy consumption, reduces the environmental pollution and recycles comprehensively water resource at the same time, reduces the discharge of wastewater greatly, increases the salinity of the discharged wastewater, reduces the difficulty of further recovery, and reduces the processing cost of wastewater greatly. The recycling of the washing wastewater of the oxalic acid precipitation reduces the impurities brought in the washing water, and improves the quality of the precipitation.

Description

technical field [0001] The invention relates to a washing method for oxalic acid precipitation, which belongs to the field of environmental protection. In particular, the invention relates to a method for recycling industrially produced oxalic acid precipitation and washing wastewater. Background technique [0002] With the vigorous development of industry, various environmental problems such as industrial waste gas and waste water have also emerged accordingly. Since industrial wastewater contains many toxic and harmful substances of different components, if it is directly discharged into rivers or seeped into the ground along with the wastewater, it will cause serious water pollution and endanger the safety of drinking water. Moreover, due to factors such as population expansion, environmental pollution, and climate change, global water resources are scarce. Water resource issues have become one of the most important issues facing mankind in the future. In order to reduc...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C02F1/26
Inventor 廖春生刘艳王嵩龄
Owner CHINA MINMETALS BEIJING RES INST OF RE
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