阅读说明：本技术 一种含铁废酸酸度的检测方法 (Method for detecting acidity of iron-containing waste acid ) 是由 杨柳荫 吴勇基 蓝立财 曾慧 丁德才 刘伟仁 樊文星 张谊彬 于 2019-08-06 设计创作，主要内容包括：本发明涉及一种含铁废酸酸度的检测方法,具体公开一种氧气氧化法生产铁盐过程中酸度检测的方法,其包括以下步骤：A、取一定量的含铁废酸,向其加入定量的酸溶液,使溶液中二价铁离子与加入酸中氢离子的摩尔比为1:1,加入当量的氧化剂,搅拌,使溶液的中二价铁离子刚好完全氧化为三价铁离子,采用铁离子测酸法,检测溶液中酸度；B、通过计量步骤A中所述酸溶液及氧化剂消耗量,计算得到所述含铁废酸的酸度。本发明方法有效解决了传统测试方法准确性差导致生产效率低及产品合格率低的问题,提高检测结果的准确性,实现了对生产过程的有效监控,提高了生产效率及产品的合格率；同时为二价铁盐的酸度检测提供一种适用的检测方法。(The invention relates to a method for detecting acidity of waste acid containing iron, and particularly discloses a method for detecting acidity in the process of producing ferric salt by an oxygen oxidation method, which comprises the following steps: A. taking a certain amount of iron-containing waste acid, adding a certain amount of acid solution into the iron-containing waste acid to ensure that the molar ratio of ferrous ions in the solution to hydrogen ions in the added acid is 1:1, adding an equivalent amount of oxidant, stirring to ensure that the ferrous ions in the solution are just completely oxidized into ferric ions, and detecting the acidity in the solution by adopting an iron ion acid detection method; B. and B, calculating the acidity of the iron-containing waste acid by metering the consumption of the acid solution and the oxidant in the step A. The method effectively solves the problems of low production efficiency and low product percent of pass caused by poor accuracy of the traditional test method, improves the accuracy of the detection result, realizes effective monitoring of the production process, and improves the production efficiency and the product percent of pass; meanwhile, an applicable detection method is provided for detecting the acidity of the ferrous salt.)

1. The method for detecting the acidity of the iron-containing waste acid is characterized by comprising the following steps of:

A. taking a certain amount of iron-containing waste acid, adding a certain amount of acid solution into the iron-containing waste acid to ensure that the molar ratio of ferrous ions in the solution to hydrogen ions in the added acid is 1:1, adding an equivalent amount of oxidant, stirring to ensure that the ferrous ions in the solution are just completely oxidized into ferric ions, and detecting the acidity in the solution by adopting an iron ion acid detection method;

B. and B, calculating the acidity of the iron-containing waste acid by metering the consumption of the acid solution and the oxidant in the step A.

2. The method for detecting acidity of waste acid containing iron according to claim 1, wherein: the acid solution in the step A is hydrochloric acid solution or sulfuric acid solution.

3. The method for detecting acidity of waste acid containing iron according to claim 1, wherein: the oxidant in the step A is one of sodium chlorate, potassium chlorate or hydrogen peroxide.

4. The method for detecting acidity of waste acid containing iron according to claim 1, wherein: the iron ion acid measurement method in the step A is a free acid measurement method in GB-T4482 & 2018 water treatment agent ferric chloride or HB-T4816 & 2015 water treatment agent ferric sulfate.

5. The method for detecting acidity of waste acid containing iron according to claim 1, wherein the mass of the acid solution consumed is m_HThe mass of the consumed oxidant is m_OThe mass of the waste acid containing iron is m_FeThe acidity measured by the iron ion acid measuring method is omega_MeasuringAnd the acidity of the iron-containing waste acid is omega, which can be obtained by the formula:

6. the method for detecting acidity of waste acid containing iron according to claim 1, wherein the acidity of the waste acid containing iron is consistent with the acidity expression method of the iron ion acidity measurement method, and the acidity is expressed in the form of hydrochloric acid or sulfuric acid.

7. The method for detecting acidity of waste acid containing iron according to claim 1, wherein the stirring in step A is electromagnetic stirring for 10 min.

Technical Field

The invention relates to the field of chemical analysis, in particular to a method for detecting acidity of iron-containing waste acid.

Background

In the process of processing and treating the surface of steel, a large amount of iron-containing waste acid is generated, has potential hazard to the ecological environment and needs to be harmlessly treated. At present, the iron-containing waste acid is subjected to harmless treatment by adopting an oxygen oxidation method to prepare an iron salt water purifying agent, the method has the advantages of simple process and low cost, can fully utilize waste resources, changes waste into valuables, and has good environmental and economic benefits.

In the process of producing iron salt by an oxygen oxidation method, the key for recycling the iron-containing waste acid is that the acidity of the iron-containing waste acid can be effectively and accurately detected. Otherwise, the method brings great difficulty to actual production, the acidity of the materials cannot be effectively monitored, the production efficiency is low, and the product percent of pass is low. The mass fraction of ferrous ions in the iron-containing waste acid is 6-10%, the mass fraction of acid is 3-5%, and the mass fraction of ferric ions is 1-2%, so that the iron ions in the iron-containing waste acid interfere with the accuracy of a detection result due to hydrolysis in the neutralization titration process. At present, in the acidity detection method of GB-T4482 & 2018 & lt/EN & gt water treatment agent ferric chloride & gt or HB-T4816 & lt/EN & gt 2015 & lt/EN & gt water treatment agent ferric sulfate & gt, potassium fluoride and ferric ions are adopted to react to generate tripotassium hexafluoroferrate (III) so as to avoid the interference of the ferric ions in the titration process. In the acidity detection method of HG-T4200-2011 industrial ferrous chloride, methyl red is used as an indicator, sodium hydroxide is used for titration, and the method still cannot avoid the interference of the hydrolysis of ferrous ions on the accuracy of a detection result; in the acidity detection method of GB/T10531-2016 water treatment agent ferrous sulfate, isopropanol is used as an extracting agent to extract sulfuric acid, and sodium hydroxide is used for titration, so that the method has a small application range and cannot effectively detect the acidity of a ferrous ion solution.

In the prior art, the acidity test method for the iron-containing waste acid has poor accuracy, so that ferrous ions and acidity in a raw material liquid can not be accurately matched in the process of producing ferric salt by oxidizing oxygen, the raw material matching needs to be intermittently adjusted for many times, continuous production can not be carried out, and the production efficiency is low; the acidity in the production process can not be effectively monitored, and the product percent of pass is low.

Disclosure of Invention

Aiming at the defects of the prior art, the invention provides the method for detecting the acidity of the waste acid containing iron, which can effectively avoid the interference of the hydrolysis of ferrous ions, improve the accuracy of a detection result, realize the effective monitoring of the production process and improve the production efficiency and the qualification rate of products. The method has simple steps and convenient operation, and provides an applicable detection method for detecting the acidity of the ferrous salt.

The method mainly comprises the following steps:

A. taking a certain amount of iron-containing waste acid, adding a certain amount of acid solution into the iron-containing waste acid to ensure that the molar ratio of ferrous ions in the solution to hydrogen ions in the added acid is 1:1, adding an equivalent amount of oxidant, electromagnetically stirring for 10 minutes to ensure that the ferrous ions in the solution are just completely oxidized into ferric ions, and detecting the acidity in the solution by adopting an iron ion acid detection method;

B. and B, calculating the acidity of the iron-containing waste acid by metering the consumption of the acid solution and the oxidant in the step A.

In one embodiment, the acid solution in step a is a hydrochloric acid solution or a sulfuric acid solution.

In one embodiment, the oxidant in step a is one of sodium chlorate, potassium chlorate or hydrogen peroxide.

In one embodiment, the iron ion acid measurement method in the step A is a free acid measurement method in GB-T4482 & 2018 water treatment agent ferric chloride or HB-T4816 & 2015 water treatment agent ferric sulfate.

In one embodiment, the mass of the acid consumption solution is m_HThe mass of the consumed oxidant is m_OThe mass of the waste acid containing iron is m_FeThe iron ion acid methodTo obtain the acidity of omega_MeasuringAnd the acidity of the iron-containing waste acid is omega, which can be obtained by the formula:

in one embodiment, the acidity of the waste acid containing iron is consistent with the acidity expression method of the iron ion acidity measurement method, and the acidity is expressed in the form of hydrochloric acid or sulfuric acid.

Compared with the prior art, the invention has the beneficial effects that:

1. according to the method, quantitative acid solution and oxidant are added into the iron-containing waste acid, ferrous ions in the iron-containing waste acid are just completely oxidized into ferric ions, and a masking agent is added for acidity detection. Effectively avoids the interference of ferrous ions in the detection process and improves the accuracy of the detection result.

2. The method has the advantages of simple steps, convenient operation, common and easily obtained reagents, no need of organic chemical agents, environmental protection and safety.

3. The production efficiency of iron-containing waste acid in producing iron salt by oxygen oxidation is effectively improved, continuous production is realized, the production process is monitored in real time, the product percent of pass is improved, and good economic benefit is created.

4. The method has wide application range, and is not only suitable for detecting the acidity of the iron-containing waste acid, but also can be used for detecting the acidity of the ferrous salt.

Drawings

FIG. 1 is a schematic flow chart of a method for detecting acidity of waste acid containing iron.

Detailed Description

In order to make the aforementioned objects, features and advantages of the present invention comprehensible, embodiments accompanied with figures are described in detail below. In the following description, numerous specific details are set forth in order to provide a thorough understanding of the present invention. This invention may, however, be embodied in many different forms and should not be construed as limited to the embodiments set forth herein, but rather should be construed as broadly as the present invention is capable of modification in various respects, all without departing from the spirit and scope of the present invention.

The invention provides a method for detecting acidity of waste acid containing iron. The detection method comprises the following steps:

step S110, a certain amount of iron-containing waste acid is taken, a certain amount of acid solution is added into the iron-containing waste acid, the molar ratio of ferrous ions in the solution to hydrogen ions in the added acid is 1:1, equivalent oxidant is added, electromagnetic stirring is carried out for 10 minutes, the ferrous ions in the solution are just completely oxidized into ferric ions, and the acidity in the solution is detected by adopting an iron ion acid detection method.

And step S120, calculating the acidity of the waste acid containing iron by metering the consumption of the acid solution and the oxidant in the step S110.

In this embodiment, if sodium chlorate is used as the oxidant, the reaction equation involved is as follows:

6Fe²⁺+6H⁺+NaClO₃＝6Fe³⁺+3H₂O+NaCl

according to a chemical equation, the molar ratio of the acid solution to the ferrous ions is 1:1, and then the oxidant is added, so that the ferrous ions in the waste acid containing iron are just completely oxidized into ferric ions, and the acidity of the waste acid containing iron after oxidation can be accurately measured by only masking the ferric ions in the titration process. And finally, calculating to obtain the acidity of the iron-containing waste acid according to the amount of the acid solution and the oxidant consumed in the process.

In one embodiment, the acid solution may be hydrochloric acid solution or sulfuric acid solution, and the molar ratio of the acid solution to the ferrous ions is 1: 1. It is understood that: when the acid solution is hydrochloric acid, the molar ratio of ferrous ions in the iron-containing waste acid to hydrogen chloride in the hydrochloric acid solution is 1: 1; when the solution is sulfuric acid, the molar ratio of ferrous ions in the waste acid containing iron to sulfuric acid in the sulfuric acid solution is 2: 1.

In one embodiment, the oxidant is sodium chlorate, potassium chlorate or hydrogen peroxide. It is to be noted that the amount of the oxidant added is just enough to completely oxidize the ferrous ions in the waste acid containing iron, for example, if the oxidant is sodium chlorate, the molar ratio of the ferrous ions in the waste acid containing iron to the oxidant sodium chlorate is 6: 1; if the oxidant is hydrogen peroxide, the molar ratio of ferrous ions to the oxidant sodium chlorate in the waste acid containing iron is 2: 1.

In one embodiment, the iron ion acid measurement method is a method for measuring free acid in GB-T4482 & 2018 water treatment agent ferric chloride or HB-T4816 & 2015 water treatment agent ferric sulfate. Namely, potassium fluoride is adopted as a masking agent to react with ferric ions to generate tripotassium hexafluoroferrate (III), so that the interference measurement of the ferric ions is avoided.

In step S120, the acidity of the iron-containing waste acid is calculated by metering the consumption of the acid solution and the oxidant. Firstly, taking acid liquor as hydrochloric acid and an oxidant as sodium chlorate, and according to a chemical reaction formula, calculating the process as follows:

the mass of the waste acid containing iron is m_FeThe mass fraction of ferrous ions in the waste acid containing iron is omega_Fe；

The mass of the hydrochloric acid solution is m_HThe mass fraction of hydrogen chloride in the hydrochloric acid solution is omega_H；

Sodium chlorate mass m_OSodium chlorate mass fraction of omega_O；

The acidity of the waste acid containing iron is omega, and the acidity measured by an iron ion acid measuring method is omega_Measuring；

Wherein the unit of mass is g, and the unit of mass fraction is;

firstly, calculating the adding mass of the hydrochloric acid solution according to the adding amount of the iron-containing waste acid and the mass fraction of ferrous ions of the iron-containing waste acid

Sodium chlorate addition

The acidity of the iron-containing waste acid is

Hereinafter, the method for detecting acidity of waste acid containing iron will be further described by the following specific examples.