阅读说明：本技术 一种铁盐中三氯化氮的检测方法 (Method for detecting nitrogen trichloride in ferric salt ) 是由 吴勇基 杨合雄 罗莉娟 华蔓 于 2021-08-23 设计创作，主要内容包括：本发明涉及一种铁盐中三氯化氮的检测方法,其包括以下步骤：取一定量的铁盐溶液,加入适量的亚铁溶液,调节酸度,混合均匀,使溶液中三氯化氮与二价铁离子反应,反应结束后,检测溶液中氨氮的含量；通过计量步骤A中所述亚铁溶液和酸溶液的消耗量,计算出所述铁盐中三氯化氮的含量。本发明方法能有效检测铁盐溶液中三氯化氮的含量,对铁盐生产中三氯化氮含量进行监控,避免三氯化氮的积累,为安全生产提供检测依据。本发明方法步骤简单,操作方便,安全环保,易于工业化应用。(The invention relates to a method for detecting nitrogen trichloride in ferric salt, which comprises the following steps: taking a certain amount of ferric salt solution, adding a proper amount of ferrous solution, adjusting acidity, uniformly mixing to enable nitrogen trichloride in the solution to react with ferrous ions, and detecting the content of ammonia nitrogen in the solution after the reaction is finished; and B, calculating the content of nitrogen trichloride in the ferric salt by measuring the consumption of the ferrous solution and the consumption of the acid solution in the step A. The method can effectively detect the content of nitrogen trichloride in the ferric salt solution, monitor the content of nitrogen trichloride in the ferric salt production, avoid the accumulation of nitrogen trichloride and provide a detection basis for safe production. The method has the advantages of simple steps, convenient operation, safety, environmental protection and easy industrial application.)

1. A method for detecting nitrogen trichloride in ferric salt is characterized by comprising the following steps:

s1, adding a proper amount of ferrous solution into a certain amount of ferric salt solution, adjusting acidity, uniformly mixing to enable nitrogen trichloride in the solution to react with ferrous ions, and detecting the content of ammonia nitrogen in the solution after the reaction is finished;

s2, calculating the content of nitrogen trichloride in the ferric salt by measuring the consumption of the ferrous solution and the consumption of the acid solution in the step S1.

2. The method of claim 1, wherein in step S1, the ferric salt is one or more selected from ferric trichloride, polyferric chloride, ferric sulfate, and polyferric sulfate.

3. The method of claim 1, wherein in step S1, an acid solution is added during the process of adjusting acidity, so that the molar ratio of hydrogen ions to ferrous ions is 1:4 to 1: 1.

4. The method of claim 3, wherein in step S1, an acid solution is added during the process of adjusting acidity, so that the molar ratio of hydrogen ions to ferrous ions is 2: 3.

5. The method of claim 1, wherein in step S1, the mixing uniformity comprises any one of the following: electromagnetic stirring, electric stirring, and aerating for 5-20 min.

6. The method for detecting nitrogen trichloride in an iron salt according to claim 1, wherein in step S1, the condition for ending the reaction between nitrogen trichloride and the ferrous ion is that the concentration of the ferrous ion in the solution is 0.1% -1.0%.

7. The method for detecting nitrogen trichloride in iron salt according to claim 1, wherein in step S1, the method for detecting the content of ammonia nitrogen is Kjeldahl method.

8. The method for detecting nitrogen trichloride in iron salt according to claim 1, wherein in step S2, the mass of the iron salt solution isThe mass fraction of ammonia nitrogen isPercent; the addition amount of the ferrous solution isThe mass fraction of ammonia nitrogen isPercent; the adding amount of the acid solution is(ii) a The mass fraction of ammonia nitrogen after the reaction isPercent; the mass fraction of nitrogen trichloride of the ferric salt isIn percent, thenThe following calculation formula can be used:

。

Technical Field

The invention relates to the field of chemical analysis and detection, in particular to a method for detecting nitrogen trichloride in ferric salt.

Background

Nitrogen trichloride having the formula NCl₃The relative molecular mass is 120.5, the crystal is yellow oily volatile liquid with pungent smell, and the crystal is rhombohedral crystal. Nitrogen trichloride is active and dangerous, and has strong stimulation effect on skin, eyes, mucous membrane and respiratory system. Nitrogen trichloride smoke is tear-inducing and has a corrosivity similar to chlorine. The gas phase has an explosion risk at a volume concentration of 5-6%If the concentration of the chlorine in the liquid chlorine exceeds 0.2%, there is a risk of explosion.

At present, nitrogen trichloride is mainly used for chlorine gas, chlorine gas is introduced into concentrated hydrochloric acid solution containing mercuric chloride, the nitrogen trichloride is reduced to generate ammonium chloride, the generated ammonium chloride reacts with a Nashi reagent after hydrochloric acid is separated, an orange-yellow mercuric iodide complex is generated, and a spectrophotometer is used for colorimetric determination at the wavelength of 420 nm. Although the method can effectively detect the content of the nitrogen trichloride in the chlorine gas, the method has the following defects, such as: a matched absorption device is needed; a certain amount of hydrochloric acid needs to be evaporated for measuring the ammonia nitrogen in the solution, the steps are complicated, and the process is complex; chlorine is generated in the reaction, and the safety and the environmental protection are poor. In addition, no test method for nitrogen trichloride in liquid materials has been reported.

Disclosure of Invention

Aiming at the defects of the prior art, the invention provides a method for detecting nitrogen trichloride in ferric salt, which can effectively detect the content of nitrogen trichloride in ferric salt, monitor the content of nitrogen trichloride in ferric salt production and provide a detection basis for safe production. The method disclosed by the invention is simple in steps, convenient to operate, safe and environment-friendly, and is also suitable for detecting the nitrogen trichloride in the liquid material.

The technical scheme of the invention is as follows:

a method for detecting nitrogen trichloride in ferric salt is characterized by comprising the following steps:

s1, adding a proper amount of ferrous solution into a certain amount of ferric salt solution, adjusting acidity, uniformly mixing to enable nitrogen trichloride in the solution to react with ferrous ions, and detecting the content of ammonia nitrogen in the solution after the reaction is finished;

s2, calculating the content of nitrogen trichloride in the ferric salt by measuring the consumption of the ferrous solution and the consumption of the acid solution in the step S1.

Further, in step S1, the iron salt may be one or more of ferric chloride, polyferric chloride, ferric sulfate, and polyferric sulfate.

Further, in step S1, during the acidity adjustment, an acid solution is added to make the molar ratio of hydrogen ions to ferrous ions be 1: 4-1: 1.

Further, in the step S1, during the acidity adjustment, an acid solution is added so that the molar ratio of hydrogen ions to ferrous ions is 2: 3.

Further, in step S1, the mixing manner includes any one of the following: electromagnetic stirring, electric stirring, and aerating for 5-20 min.

Further, in step S1, the reaction termination condition of nitrogen trichloride and ferrous ion is that the concentration of ferrous ion in the solution is 0.1% to 1.0%.

Further, in step S1, the method for detecting the content of ammonia nitrogen is a kjeldahl method in the prior art, and a kjeldahl apparatus is used to determine ammonia nitrogen in the material.

Further, in step S2, the mass of the ferric salt solution isThe mass fraction of ammonia nitrogen isPercent; the addition amount of the ferrous solution isThe mass fraction of ammonia nitrogen isPercent; the adding amount of the acid solution is(ii) a The mass fraction of ammonia nitrogen after the reaction isPercent; the mass fraction of nitrogen trichloride of the ferric salt isIn percent, thenThe following calculation formula can be used:

。

wherein 123.39 is the relative molecular mass of nitrogen trichloride, and 14.01 is the relative atomic mass of nitrogen.

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

1. according to the method, a ferrous solution is added into an iron salt solution, the acidity is adjusted, nitrogen trichloride in the iron salt is reduced into ammonia nitrogen, the ammonia nitrogen in the solution is detected, and the content of the nitrogen trichloride in the iron salt can be obtained by calculating the change and conversion of the ammonia nitrogen before and after the material. The method is simple and convenient, simple in process, easy to operate, common and easily available in reagent, environment-friendly and safe, and does not need special devices for treatment.

2. The method can effectively detect the content of nitrogen trichloride in the ferric salt, monitor the content of nitrogen trichloride in the production of the ferric salt, provide a detection basis for safe production, and particularly provide a detection basis in the process of using raw materials with higher ammonia nitrogen content.

3. The method has wide application range, is not only suitable for detecting the nitrogen trichloride in the ferric salt, but also can be used for detecting the nitrogen trichloride in the liquid.

Detailed Description

In order that the above objects, features and advantages of the present invention will be readily understood, numerous specific details are set forth in the following description 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 nitrogen trichloride in ferric salt. The detection method comprises the following steps:

the method comprises the following steps: taking a certain amount of ferric salt solution, adding a proper amount of ferrous solution, adjusting acidity, uniformly mixing to enable nitrogen trichloride in the solution to react with ferrous ions, and detecting the content of ammonia nitrogen in the solution after the reaction is finished;

in one embodiment, the iron salt is added with appropriate amounts of ferrous solution and acid solution, the primary purpose of which is to reduce the nitrogen trichloride produced, involving the following reaction:

adding an acid solution so that the molar ratio of the hydrogen ions to the ferrous ions is 1:4 to 1: 1. Preferably, the molar ratio of the ferrous iron ions to the hydrogen ions can be 3: and 2, reducing the nitrogen trichloride in the material into ammonia nitrogen, detecting the ammonia nitrogen in the material after reaction, and calculating to obtain an ammonia nitrogen increase value in the material, wherein the ammonia nitrogen increase value is the reduction production of the nitrogen trichloride. And finally, calculating the content of the nitrogen trichloride in the ferric salt according to the amount of the ferrous solution and the acid solution.

In one embodiment, the iron salt can be ferric chloride, polyferric chloride, ferric sulfate, polyferric sulfate, and the test method of nitrogen trichloride can be applicable.

In one embodiment, in order to ensure that the nitrogen trichloride is fully reduced, the mass of the ferrous solution is added in excess, namely the mass fraction of ferrous iron in the solution after the reaction is finished is 0.1-1%. Meanwhile, in the acid adjusting process, the acid solution is added in an amount that the molar ratio of the hydrogen ions to the ferrous ions is 2: 3. in the reaction, the ferrous solution is excessive, and the acid solution is excessive in corresponding proportion, so that on one hand, the concentration of reactants is increased, and the reaction is accelerated; on the other hand, the addition amount of the ferrous solution is not too much, which causes the increase of the addition amount of the acid solution and waste to a certain extent.

In one embodiment, in order to make the materials fully contact, the materials can be fully mixed by adopting an electromagnetic stirring, electric stirring or aeration mode, the mixing time is 5-20min, and preferably, the mixing time is 10min, and then the reaction can be completed.

Step two: and calculating the content of nitrogen trichloride in the ferric salt by measuring the consumption of the ferrous solution and the consumption of the acid solution in the step one.

Firstly, taking ferric salt as ferric trichloride, ferrous solution as ferrous chloride and acid solution as hydrochloric acid, and according to a chemical reaction formula, calculating the following steps:

the mass of ferric trichloride isThe mass fraction of ammonia nitrogen is%；

The ferrous chloride solution is added in an amount ofThe mass fraction of ammonia nitrogen is%；

The addition amount of the hydrochloric acid solution isThe mass fraction of ammonia nitrogen in the solution after the reaction is finished is%；

The mass fraction of nitrogen trichloride in the ferric trichloride is% wherein the units of mass are g.

The nitrogen trichloride reacts with ferrous iron and acid and is reduced to generate ammonium chloride, wherein the nitrogen trichloride is reduced to generate an ammonia nitrogen value (%):(ii) a Then the mass fraction of the nitrogen trichloride in the ferric trichloride is obtained through the calculation of a chemical reaction equation% is:

equation (1).

Hereinafter, the method for detecting nitrogen trichloride in an iron salt will be further described with reference to the following specific examples.

Example 1

100.0g of ferric chloride solution is taken out of a beaker, the ammonia nitrogen mass fraction is detected to be 0.04%, and 25.0g of ferrous chloride solution (Fe)²⁺：13.49%，NH₃-N: 0.014%, HCl: 2.65%), 3.0g hydrochloric acid solution (HCl: 25.20 percent) and is electromagnetically stirred for 10 minutes, after the reaction is finished, the mass fractions of the ferrous iron and the ammonia nitrogen of the detected materials are respectively 0.41 percent and 0.043 percent, and the nitrogen trichloride content in the ferric trichloride is 0.08 percent through calculation of the formula (1).

Example 2

100.0g of poly ferric chloride solution is taken out of a beaker, the ammonia nitrogen mass fraction is detected to be 0.05 percent, and 20.0g of ferrous chloride solution (Fe) is added²⁺：10.49%，NH₃-N: 0.007%, HCl: 1.65%), add 2.8g hydrochloric acid solution (HCl: 20.20 percent) and electrically stirred for 10 minutes, after the reaction is finished, the mass fractions of ferrous and ammonia nitrogen of the detected materials are respectively 0.18 percent and 0.045 percent, and the nitrogen trichloride content in the ferric trichloride is 0.03 percent through the calculation of the formula (1).

Example 3

100.0g of ferric sulfate solution is taken out of a beaker, the ammonia nitrogen mass fraction is detected to be 0.12%, and 30.0g of ferrous chloride solution (Fe)²⁺：10.49%，NH₃-N: 0.007%, HCl: 1.65%), 4.3g hydrochloric acid solution (HCl: 20.20 percent) and aerating for 10 minutes, wherein after the reaction is finished, the mass fractions of ferrous and ammonia nitrogen of the detected materials are respectively 0.15 percent and 0.105 percent, and the nitrogen trichloride content in the ferric trichloride is 0.12 percent through calculation of the formula (1).

Example 4

100.0g of polymeric ferric sulfate solution is put into a beaker for detectionMeasuring the ammonia nitrogen mass fraction to be 0.23%, adding 20.0g ferrous chloride solution (Fe)²⁺：10.49%，NH₃-N: 0.007%, HCl: 1.65%), and 2.88g of hydrochloric acid solution (HCl: 20.20 percent) and is electromagnetically stirred for 10 minutes, after the reaction is finished, the mass fractions of the ferrous iron and the ammonia nitrogen of the detected materials are respectively 0.25 percent and 0.195 percent, and the nitrogen trichloride content in the ferric trichloride is 0.06 percent through the calculation of the formula (1).

It will be evident to those skilled in the art that the invention is not limited to the details of the foregoing illustrative embodiments, and that the present invention may be embodied in other specific forms without departing from the spirit or essential attributes thereof. The present embodiments are therefore to be considered in all respects as illustrative and not restrictive, the scope of the invention being indicated by the appended claims rather than by the foregoing description, and all changes which come within the meaning and range of equivalency of the claims are therefore intended to be embraced therein.

Furthermore, it should be understood that although the present description refers to embodiments, not every embodiment may contain only a single embodiment, and such description is for clarity only, and those skilled in the art should integrate the description, and the embodiments may be combined as appropriate to form other embodiments understood by those skilled in the art. It should be noted that the technical features not described in detail in the present invention can be implemented by any prior art in the field.