Method for recycling phosphorus and fluorine in defluorination residues

A technology for defluorinated slag and phosphoric acid, applied in chemical instruments and methods, phosphate fertilizers, phosphate, etc., can solve problems such as defluorinated slag being put into the market, crop poisoning, and recycling of fluorine-free resources, achieving strong demonstration significance and promotion value , easy to promote, and improve the effect of using value

Active Publication Date: 2012-06-20
WENGFU (GRP) CO LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

When the defluorinated slag is directly used as coarse fertilizer and applied to crops, it may cause poisoning of crops due to its rich F
Therefore, the defluoridation slag can neither be directly put into the market as a commercial fertilizer, but also limited as a raw material for compound fertilizer
[0003] In the patent literature with the application number 97107676, a kind of "method for producing ammonium phosphate fertilizer by using wet phosphate waste residue" is disclosed, the method includes passing through wet

Method used

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  • Method for recycling phosphorus and fluorine in defluorination residues
  • Method for recycling phosphorus and fluorine in defluorination residues

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0025] Weigh 1000g of defluorination slag (P 2 o 5 content 29.8%, F content 7.1%, CaO content 30.1%, free water 5%), 98% sulfuric acid 554g, phosphoric acid back acid 4150g (P 2 o 5 Content 18.1%) quantitatively and continuously fed into the acid reaction tank, referring to the traditional method of sulfuric acid decomposition of phosphate rock, the reaction conditions are: control SO 3 The concentration is about 35g / L, the reaction temperature is 78°C, the reaction time is 4 hours, and the liquid-solid ratio is about 4:1. After the reaction is completed, filter, wash, and filter the obtained dilute phosphoric acid P 2 o 5 The content is about 26.1%, and the F content is about 5.6%. Take 1085g of dilute phosphoric acid as dilute phosphoric acid product and enter the concentration section.

[0026] Concentrate the above 1085g of dilute phosphoric acid at an absolute pressure of 10kPa and 75°C to obtain 611g of concentrated phosphoric acid (P 2 o 5 content of about 46...

Embodiment 2

[0028] Weigh 1650g of defluorination slag (P 2 o 5 content 13.7%, F content 4.8%, CaO content 28.1%, free water 39%), 98% sulfuric acid 850g, phosphoric acid back acid 4810g (P 2 o 5 Content 15.7%) quantitatively and continuously fed into the acid reaction tank, referring to the traditional method of sulfuric acid decomposition of phosphate rock, the reaction conditions are: control SO 3 The concentration is about 25g / L, the reaction temperature is 75°C, the reaction time is 3 hours, and the liquid-solid ratio is about 3.5:1. After the reaction is completed, filter, wash, and filter the obtained dilute phosphoric acid P 2 o 5 The content is about 18.2%, and the F content is about 5.7%. Take 1182g of dilute phosphoric acid as dilute phosphoric acid product and enter the concentration section.

[0029] Concentrate the above 1182g of dilute phosphoric acid at an absolute pressure of 11kPa and 80°C to obtain 607g of concentrated phosphoric acid (P 2 o 5content of about 35.3...

Embodiment 3

[0031] Weigh 1315g of defluorination slag (P 2 o 5 content 25.1%, F content 8.75%, CaO content 35.8%, free water 24%), 98% sulfuric acid 1008g, phosphoric acid back acid 2390g (P 2 o 5 Content 20.8%) quantitatively and continuously fed into the acid reaction tank, referring to the traditional method of sulfuric acid decomposition of phosphate rock, the reaction conditions are: control SO 3 The concentration is about 80g / L, the reaction temperature is 95°C, the reaction time is 1 hour, and the liquid-solid ratio is about 2:1. After the reaction is completed, filter, wash, and filter the obtained dilute phosphoric acid P 2 o 5 The content is about 28.1%, and the F content is about 9.1%. Take 1105g of dilute phosphoric acid as dilute phosphoric acid product and enter the concentration section.

[0032] Concentrate the above 1105g of dilute phosphoric acid at an absolute pressure of 10kPa and 78°C to obtain 578g of concentrated phosphoric acid (P 2 o 5 content of ab...

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Abstract

The invention discloses a method for recycling phosphorus and fluorine in defluorination residues. The method comprises the following steps of: returning sulfuric acid and a certain amount of phosphoric acid to decompose the defluorination residues, extracting the phosphorus and the fluorine in the defluorination residues to generate bi-water or semi-water calcium sulfate crystals and a dilute phosphoric acid solution, performing solid-liquid separation, and thus obtaining dilute phosphoric acid and a byproduct, namely ardealite; concentrating the dilute phosphoric acid to obtain concentratedphosphoric acid, recycling overflow fluorine-containing gas in the phosphoric acid concentrating process and the acid preparing process to obtain fluorides such as fluosilicic acid and the like, or adding a defluorination agent into the dilute phosphoric acid, and recycling fluorine resources in a mode of the fluorides such as sodium fluosilicate and the like; and processing the obtained concentrated phosphoric acid by the conventional method, and thus obtaining phosphate products such as ammonium phosphate and the like. By the method, phosphorus and fluorine resources in the defluorination residues can be effectively recycled, wastes are made profitable, and the recycling value of the phosphorus and the fluorine in the defluorination residues is improved.

Description

technical field [0001] The invention relates to sewage treatment, in particular to a method for recovering phosphorus and fluorine in defluorination slag. Background technique [0002] At present, the defluorination press filter process is usually used in my country to prepare feed grade calcium hydrogen phosphate. The large amount of waste residue produced in the defluorination section is called defluorination residue (also known as "white fertilizer"), and the defluorination residue is a cement-like mass. , rich in phosphorus and fluorine resources, the dry basis of the defluorination slag generally contains 15% to 30% of P 2 o 5 and 5% to 15% of F. At present, the recycling of defluorinated slag is to dry it and use it as raw material of rough manure or compound fertilizer. However, due to the P contained in the defluorination slag 2 o 5 citrate soluble P 2 o 5 , when used to produce compound fertilizers, the water-soluble P content required in GB15063-2009 cannot...

Claims

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Application Information

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IPC IPC(8): C01B25/28C01F11/46C05B7/00C02F1/58
Inventor 刘旭胡厚美胡宏郭举李艳夏循峰
Owner WENGFU (GRP) CO LTD
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