Method for deeply purifying phosphorous and fluorine co-existing wastewater

Abstract

The invention discloses a method for deeply purifying phosphorous and fluorine co-existing wastewater. The method comprises the following steps: controlling removal of fluorine in polluted water by adopting Friedal salt dissolution-precipitation and ionic exchange reaction; controlling removal of phosphorous in the polluted water by adopting chemical precipitation of calcium ions and complex precipitation of a Fe-Al-Ca phosphate removing agent; completing the Friedal salt dissolution-precipitation, ionic exchange reaction, chemical precipitation of calcium ions and complex precipitation of theFe-Al-Ca phosphate removing agent under the condition of the same pH value variation in the same reactor so as to realize synchronous performance of multiple phosphorous-removing and defluorination reactions. According to the method, the technology of using Friedal salt as an absorbent for controlling fluorine removal and the technology of synchronously removing phosphorous and fluorine with Fe-Al-Ca phosphate removing agent and lime milk to control phosphorous absorption are adopted for the first time, so that synchronous performance of multiple phosphorous removing and defluorination reactions under the condition of same pH value variation in the same reactor can be realized.

Description

technical field [0001] The invention belongs to the technical field of water body pollution control in the inorganic chemical industry, and particularly relates to a method for synchronously removing phosphorus and fluorine in water bodies polluted by inorganic phosphorus chemical industry by using Fred's salt in combination with a Fe-Al-Ca phosphorus removal agent. Background technique [0002] During the development and utilization of phosphate rock in my country, more than 1 million tons of fluorine enter the environment every year, and a large part of it is discharged into the water environment through wastewater. With the promulgation of the "Inorganic Chemical Industry Pollutant Discharge Standard" (GB31573-2015), it will be fully implemented on July 1, 2017; the national standard "Inorganic Phosphorus Chemical Industrial Pollutant Discharge Standard" is also under review and will be implemented in 2018. The country has stricter water pollution control and management o...

AI Technical Summary

Problems solved by technology

[0015] 2. Constraints of existing technologies

[0032] ⑴. Under the condition of coexistence of phosphorus and fluorine, controlled by the solubility product of the reaction precipitation product, the removal of fluorine cannot meet the standard and becomes the key constraint

[0038] Generally speaking, the shortcomings of the existing phosphorus and fluorine coexisting wastewater treatment technologies are: the process is becoming more and more complex, the energy consumption of pumping and stirring is high, the pH value operation flexibility is small, the utilization rate of chemicals is low, and the defluorination is not easy to reduce the standard, etc.

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