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Method for recovering high-purity products from acid washing waste liquid step by step

A high-purity technology for pickling waste liquid, applied in chemical instruments and methods, fluorosilicic acid, nitrogen compounds, etc. Sodium fluorosilicate is difficult to achieve and other problems, to achieve the effect of good recovery effect, low cost and easy separation

Pending Publication Date: 2020-04-10
ZHEJIANG HAIHE ENVIRONMENTAL TECH
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

On the one hand, lead ions are highly toxic pigments that are strictly controlled in terms of chemical industry and environmental pollution. Human body intake of lead will lead to blood lead disease; on the other hand, after the lead sulfate solution is produced in the waste acid, there will also be There are more sulfate radicals and lead ions, and sulfate radicals and lead ions are strict control indicators that affect the product specifications of sodium fluorosilicate. It is difficult for the recovered sodium fluorosilicate to meet GB / T36936-2018
[0004] 2. The products of fluorosilicate and nitrate recovered by the above patent application have not been tested, and it is unknown whether they meet the national standard or industry standard

Method used

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  • Method for recovering high-purity products from acid washing waste liquid step by step
  • Method for recovering high-purity products from acid washing waste liquid step by step
  • Method for recovering high-purity products from acid washing waste liquid step by step

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Experimental program
Comparison scheme
Effect test

Embodiment 1

[0046] The composition and substance content of the pickling waste liquid used in this embodiment are shown in Table 1 for details.

[0047]Pickling waste liquor composition and content list in the embodiment 1 of table 1

[0048] component name Mass fraction of each substance (%) h 2 SiF 6

10.8 HF 5.2 HNO 3

6.9 h 2 SO 4

0.8 Na 0.8 h 2 o

75.5

[0049] A method for recovering high-purity products step by step from pickling waste liquid of the present embodiment comprises the following steps:

[0050] Step 1, reclaim fluorosilicate;

[0051] First add silicon to the pickling waste liquid to convert HF in the waste liquid into H 2 SiF 6 ;

[0052] and then converted to H 2 SiF 6 The first precipitating agent is added in the waste liquid, and the first precipitating agent is sodium sulfate.

[0053] Sodium fluorosilicate is generated, and the precipitate is filtered to obtain the first mother liquor;

...

Embodiment 2

[0077] The main difference between this embodiment and embodiment 1 is:

[0078] The HF conversion used in step one is SiO 2 , the first precipitant is sodium chloride; the second precipitant is barium chloride in step 2, and the specific consumption is shown in table 5.

[0079] The output, purity and corresponding impurity situation of the target product sodium fluorosilicate, barium sulfate and sodium nitrate that the present embodiment reclaims are shown in Table 6 for details. See Table 7 for the composition of the solution after cooling and crystallization in Step 3.

[0080] Table 5 embodiment 2 step one to step three used process conditions, material and consumption situation

[0081]

[0082]

[0083] Table 6 embodiment 2 reclaims target product purity situation

[0084]

[0085] Solution composition situation after step 3 cooling crystallization in the embodiment 2 of table 7

[0086] main components quality score sodium sulfate 1.13％ ...

Embodiment 3

[0088] The main difference between this embodiment and embodiment 1 is:

[0089] The HF conversion used in step one is SiO 2 , the first precipitant is sodium hydroxide; the second precipitant is barium chloride in step 2, and the specific consumption is shown in table 8.

[0090] The output, purity and corresponding impurity situation of the target product sodium fluorosilicate, barium sulfate and sodium nitrate that the present embodiment reclaims are shown in Table 9 for details. The composition of the solution after cooling and crystallization in step 3 is shown in Table 10.

[0091] Table 8 embodiment 3 steps one to step three used process conditions, material and consumption situation

[0092]

[0093] Table 9 embodiment 3 reclaims target product purity situation

[0094]

[0095]

[0096] The composition of the solution after step 3 cooling and crystallization in Table 10 Example 3

[0097] main components quality score sodium sulfate 1.5％...

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Abstract

The invention discloses a method for recovering high-purity products from an acid washing waste liquid step by step. The method comprises the following steps: 1, recovering fluosilicate, wherein silicon or silicon dioxide is added into an acid washing waste liquid to convert the HF in the waste liquid into H2SiF6, a first precipitant is added into the converted H2SiF6, a neutralization salifying reaction is performed to generate fluosilicate precipitate and generate a first mother liquor, and the obtained fluosilicate precipitate is cleaned, dried and powdered to obtain a first target productfluosilicate; 2, adding a second precipitant into the first mother liquor, carrying out a replacement reaction to generate sulfate precipitate and a second mother liquor, cleaning the obtained sulfateprecipitate, drying, and powdering to obtain second target sulfate; and 3, evaporating and concentrating the second mother liquor, carrying out cooling crystallizing to generate crystallized nitrate,drying, and powdering to obtain a third target product nitrate, wherein a third mother liquor is generated, 80% of the third mother liquor is refluxed and reused to be mixed with the second mother liquid, and 20% of the third mother liquor is treated according to dangerous solid waste. According to the method, high-purity fluosilicate and nitrate are sequentially recovered step by step, the recovered products can reach related standards such as GB / T36936-2018, GB / T4553-2016 and the like, the cost is low, the recovery effect of the acid washing waste liquid is good, and environmental pollutionis small.

Description

technical field [0001] The invention relates to the technical field of recycle and utilization of waste acid resources, in particular to a method for recovering high-purity products step by step from pickling waste liquid. Background technique [0002] The following technical scheme is given in "A Resource Utilization Process of Waste Acid" with the application number of 2018101391405: a precipitant is added to the first reactor to separate the lead sulfate filter residue. The purpose of this process is to remove the sulfate radical in the waste acid , the precipitant used is a soluble lead salt such as lead nitrate. But there is following defective in above-mentioned technology: [0003] 1. Pb 2+ with SO 4 2- combined with PbSO 4 It is a slightly water-soluble electrolyte with a solubility of 0.28%. Use soluble lead salts to separate sulfate ions, the effect of its separation and recovery of sulfate ions is limited, and lead ions will also be introduced in the spent a...

Claims

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Application Information

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IPC IPC(8): C01B33/10C01B17/96C01B21/48C01D9/00C01F11/46
CPCC01B17/96C01B21/48C01B33/103C01D9/00C01F11/462
Inventor 蒋正海包芳芳蒋经纬鲍桂洪
Owner ZHEJIANG HAIHE ENVIRONMENTAL TECH
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