Method for recycling tricalcium phosphate from expandable polystyrene industrial wastewater

An expandable polystyrene, tricalcium phosphate technology, applied in chemical instruments and methods, phosphorus compounds, natural water treatment, etc. The effect of reducing production costs, reducing consumption, and reducing wastewater treatment volume

Active Publication Date: 2014-07-02
见龙国际贸易有限公司
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0002] At present, most of the domestic expandable polystyrene (referred to as EPS) production plants use tricalcium phosphate as a dispersant during the suspension polymerization process. Finally, the waste water containing a large amount of inorganic phosphorus is discharged into the municipal sewage pipe after physical, chemical and biochemical treatment. If the sewage system is not treated well, it will cause environmental pollution, and the national standard GB 8978-1996 "Sewage Comprehensive Discharge Standard" stipulates that phosphate The secondary discharge standard (calculated as phosphorus) is less than 1ppm. In fact, it is difficult to meet the standard stably according to the existing water treatment process.
At present, no relevant technology has been found to recover tricalcium phosphate from EPS suspension polymerization wastewater

Method used

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  • Method for recycling tricalcium phosphate from expandable polystyrene industrial wastewater
  • Method for recycling tricalcium phosphate from expandable polystyrene industrial wastewater
  • Method for recycling tricalcium phosphate from expandable polystyrene industrial wastewater

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0024] Such as figure 1 Shown, EPS production waste water is reclaimed and prepared tricalcium phosphate by the following steps:

[0025] Step 1: Build an acidic floating pond and an alkaline floating pond

[0026] Build an acidic floating flow pool and an alkaline floating flow pool with a water storage capacity of 50 tons with a stirring device respectively. The length*width*height is: 4.5M*4.5M*3.2M (such as figure 2 and image 3 shown);

[0027] Step 2: Acid pool dissolves tricalcium phosphate in wastewater

[0028] Pump 50 tons of EPS production wastewater into the acidic floating flow tank, then add 18.9L of hydrochloric acid with a concentration of 30%, stir for 2 hours, adjust the pH value to 3.0-3.2, control the reaction temperature at 25-40°C, and after 36 hours of static sedimentation, Obtain polystyrene-containing precipitate and supernatant;

[0029] The chemical reaction that occurs in this step is: Ca 3 (PO4) 2 +2HCl=2H 3 PO 4 +3CaCl 2 ;

[0030] S...

Embodiment 2

[0042] The main technical scheme of this embodiment is the same as Embodiment 1, the difference is:

[0043] Step 1: Acid pool dissolves tricalcium phosphate in wastewater

[0044] Pump 50 tons of EPS production wastewater into an acid floating flow tank with a capacity of 50 tons, then add 23.6L of hydrochloric acid with a concentration of 25%, stir for 2.5 hours, adjust the pH value to 3.0-3.2, control the reaction temperature at 30-40°C, and settle still After 36 hours, the precipitate and supernatant containing polystyrene were obtained;

[0045] Step 3: Remove the sediment

[0046] The supernatant is pumped into the alkaline floating flow tank, and the sediment is pumped into the filter press with a mud pump to obtain polystyrene powder and remove it;

[0047] Step 4: Alkaline pool precipitation

[0048] Add 72.5L of industrial liquid caustic soda (NaOH solution) with a concentration of 25% into the alkaline floating flow pool, stir for 3 hours, adjust the pH value to ...

Embodiment 3

[0052] The main technical scheme of this embodiment is the same as Embodiment 1, the difference is:

[0053] Step 1: Acid pool dissolves tricalcium phosphate in wastewater

[0054]Pump 50 tons of EPS production wastewater into an acid floating flow tank with a capacity of 50 tons, then add 23.6L of hydrochloric acid with a concentration of 30%, stir for 3 hours, adjust the pH value to 3.2-3.5, control the reaction temperature at 25-35°C, and settle still After 32 hours, a precipitate containing polystyrene and a supernatant were obtained;

[0055] Step 3: Remove the sediment

[0056] The supernatant is pumped into the alkaline floating flow tank, and the sediment is pumped into the filter press with a mud pump to obtain polystyrene powder and remove it;

[0057] Step 4: Alkaline pool precipitation

[0058] Add 72.5L of industrial liquid caustic soda (NaOH solution) with a concentration of 30% to the alkaline floating flow pool, stir for 2 hours, adjust the pH value to 7.5-7...

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Abstract

The present invention relates to the technical field of recovery and utilization of tricalcium phosphate, in particular to a method for reclaiming tricalcium phosphate from waste water produced by expandable polystyrene. The recovery rate of tricalcium phosphate reaches 85% after physical and biochemical treatment of wastewater, which greatly reduces the amount of tricalcium phosphate required for the production of expandable polystyrene, reduces production costs, and makes waste water inorganic The rapid reduction of phosphorus content is beneficial to environmental protection and achieves double benefits of environment and economy.

Description

technical field [0001] The invention relates to the technical field of recycling of tricalcium phosphate, in particular to a method for recycling tricalcium phosphate from waste water produced by expandable polystyrene. Background technique [0002] At present, most domestic expandable polystyrene (referred to as EPS) production plants use tricalcium phosphate as a dispersant in the suspension polymerization process. If the sewage system is not properly treated, it will cause environmental pollution, and the national standard GB 8978-1996 "Comprehensive Discharge Standard for Sewage" has a secondary standard for the discharge of phosphate (calculated as phosphorus) that is less than 1ppm. In fact, it is difficult to meet the standard stably according to the existing water treatment process. According to estimates, based on the calculation of an EPS factory with an annual output of 300,000 tons, the annual usage of the dispersant tricalcium phosphate needs to be about 600 to...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C01B25/32C02F9/04C02F1/66C02F103/38
Inventor 童晓良曾首元
Owner 见龙国际贸易有限公司
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