Method for continuously measuring acidity and ferrous iron content of ferrous sulfate solution

Abstract

The invention relates to a method for continuously measuring the acidity of a ferrous sulfate solution and the content of ferrous iron, and belongs to the technical field of secondary utilization of copper smelting tailings, and the method for measuring the acidity of the ferrous sulfate solution comprises the following steps: putting 1-5mL of ferrous sulfate solution into a conical flask, adding 20-30mL of distilled water to blow and wash the cup wall, adding 2-3 drops of methyl orange indicator, titrating to yellow by using a sodium hydroxide standard solution, namely a titration end point, and calculating the acidity (PHB = V1 * TH2SO4 / NaOH / Vtaking) according to the consumption of sodium hydroxide; 10-15 mL of sulfur and phosphorus mixed acid is added into a conical flask, then 6-7 drops of sodium diphenylaminesulfonate indicator is dropped into the conical flask, the solution is pink at the moment, a potassium dichromate standard solution is used for titration until the solution is purple, the titration end point is obtained, and the content of the ferrous iron is calculated according to the consumption of the potassium dichromate (w = V1 * TFe / K2Cr2O7) / Vtaking. Through continuous determination, the waiting time and the sample processing time are reduced, so that the determination period is shortened to half an hour from the traditional 1 hour, and the production efficiency is remarkably improved.

Description

Technical Field

[0001] The invention belongs to the technical field of secondary utilization of copper smelting tailings, and particularly relates to a method for continuously measuring the acidity and divalent iron content of a ferrous sulfate solution. Background Art

[0002] Copper smelting tailings are an important raw material for the preparation of ferrous sulfate. In this process, acidity and the content of ferrous iron have a crucial impact on the quality and production efficiency of the product. First of all, the control of acidity plays a key role in the preparation of ferrous sulfate. The acid we use is mainly sulfuric acid, and its concentration and dosage directly affect the production efficiency and purity of ferrous sulfate. During the preparation process, sulfuric acid reacts chemically with the iron element in the tailings to produce ferrous sulfate. Therefore, the dosage of sulfuric acid must be strictly controlled to ensure the full conversion of iron elements and the generation of ferrous sulfate. Secondly, ferrous iron is one of the main raw materials for the preparation of ferrous sulfate. Copper smelting tailings are rich in iron elements, which are converted into ferrous sulfate under the action of sulfuric acid. The content of ferrous iron directly affects the output and purity of ferrous sulfate. If the content of ferrous iron in the tailings is low, more tailings are needed to prepare the same amount of ferrous sulfate, which will increase production costs and energy consumption.

[0003] At present, the acid-base titration method is usually used to determine the acidity of ferrous sulfate solution. This method adds a standard alkali solution to the solution to be tested, uses an acid-base indicator to determine the titration endpoint, and finally calculates the acidity of the solution based on the volume of the consumed standard alkali solution. However, this method has the problems of cumbersome operation and inaccurate endpoint judgment, especially for complex systems containing polyacids or polyvalent metals, the endpoint change is often not obvious, resulting in inaccurate measurement results.

[0004] The determination of iron content in ferrous sulfate solution usually adopts redox titration. Commonly used reducing agents include sodium sulfite, sodium stannate, etc., while potassium permanganate is often used as an oxidant. During the determination process, the titration conditions, such as temperature, pH value, etc., need to be strictly controlled to ensure the accuracy of the measurement results. However, this method also has problems such as cumbersome operation and susceptibility to interference, especially for systems containing other reducing substances, which can easily cause deviations in the measurement results. Summary of the invention

[0005] The purpose of the present invention is to provide a method for continuously measuring the acidity and ferrous iron content of ferrous sulfate solution in order to solve the above problems.

[0006] The present invention achieves the above-mentioned purpose through the following technical solutions:

[0007] The present invention provides a method for continuously measuring the acidity and ferrous iron content of a ferrous sulfate solution, comprising the following steps:

[0008] Step S1, preparing carbon dioxide pellets: (i) preparing pelleting liquid: placing casein, gum arabic, charcoal powder, tannic acid and pectin in a wall breaking machine, performing wall breaking treatment for 5-8 minutes, and obtaining a mixed powder; mixing the mixed powder with pure water, adding the mixture into a centrifugal stirrer, performing centrifugal stirring treatment, stirring at 600-1000r / min for 15-30 minutes, and obtaining a pelleting liquid; (ii) dividing solid carbon dioxide into rectangular blocks with a length, width and height of 2×3×1.5nm; (iii) adding the pelleting liquid into a high-voltage electrospinning device, dividing the rectangular blocks into three equal parts, and then surrounding the three groups of rectangular blocks with spraying silk film to obtain carbon dioxide pellets, which are stored at low temperature at -60°C for standby use.

[0009] Step S2, preparing a sterile environment agent: adding sodium hypochlorite to pure water, stirring for 30-45 minutes, to obtain a sodium hypochlorite solution;

[0010] Glutaraldehyde was added at the 10th minute of stirring, and then hydrogen peroxide was added at the 25th minute of stirring, and the mixture was fully mixed to obtain a preformed liquid;

[0011] The pre-made solution was stored at 2-5°C and carbon dioxide was added to the pellets 20-30 minutes before use to obtain a sterile environment agent;

[0012] Step S3, placing the sterilant inside the test box, and starting to measure the acidity of the ferrous sulfate solution after 5-15 minutes;

[0013] Step S4, determining the acidity of the ferrous sulfate solution: taking a volume of 1-5 mL of ferrous sulfate solution in a conical flask, adding 20-30 mL of distilled water to purge the cup wall, adding 2-3 drops of methyl orange indicator, at this time the liquid is orange-red, using a sodium hydroxide standard solution to titrate to yellow, this is the titration end point, and the acidity is calculated by the sodium hydroxide consumption (PHB = V1 × TH2SO4 / NaOH) / Vtake);

[0014] The specific reaction equation is as follows: H2SO4+2NaOH=Na2SO4+2H2O;

[0015] Step S5, determining the ferrous iron content: adding 10-15 mL of sulfur-phosphorus mixed acid into a conical flask, and then dropping 6-7 drops of sodium diphenylamine sulfonate indicator, the solution is now pink, and titrated with potassium dichromate standard solution until it turns purple, which is the titration end point, and calculating the ferrous iron content by the potassium dichromate consumption (w=V1×TFe / K2Cr2O7) / Vtake);

[0016] The specific reaction equation is as follows: K2Cr2O7+6FeSO4+7H2SO4=3Fe2(SO4)3+Cr2(SO4)3+K2SO4+7H2O.

[0017] As a further optimization scheme of the present invention, the conductivity of the distilled water is ≤0.50mS / m, and the pH is 5.0-7.5.

[0018] As a further optimization scheme of the present invention, the preparation method of the sulfur-phosphorus mixed acid is: mixing phosphoric acid, sulfuric acid and water to obtain the sulfur-phosphorus mixed acid, and the mass ratio of the phosphoric acid, sulfuric acid and water is 1:1:3.

[0019] As a further optimization scheme of the present invention, the concentration of the methyl orange indicator is 5 g / L; the concentration of the sodium diphenylamine sulfonate indicator is 5 g / L.

[0020] As a further optimization scheme of the present invention, the titer of the sodium hydroxide standard solution is 0.02434 g / mL; the titer of the potassium dichromate standard solution is 0.005585 g / mL.

[0021] As a further optimization scheme of the present invention, the time for the first group of cuboids to surround the sprayed silk film is 5 minutes; the time for the second group of cuboids to surround the sprayed silk film is 8 minutes; and the time for the third group of cuboids to surround the sprayed silk film is 11 minutes.

[0022] As a further optimization scheme of the present invention, the raw materials for preparing the pill-packing liquid include, by weight: 3-8 parts of casein, 3-8 parts of gum arabic, 10-20 parts of charcoal powder, 1-3 parts of tannic acid, 6-12 parts of pectin and 40-50 parts of pure water.

[0023] As a further optimization scheme of the present invention, the raw materials for preparing the sterile environment agent include, by weight: 5-10 parts of sodium hypochlorite, 10-25 parts of pure water, 6-10 parts of hydrogen peroxide and 8-16 parts of carbon dioxide pellets.

[0024] The beneficial effects of the present invention are as follows: through continuous measurement, the waiting time and sample processing time are reduced, so that the measurement cycle is shortened from the traditional one hour to half an hour, thereby significantly improving the production efficiency; by accurately controlling the acidity and the divalent iron content of the ferrous sulfate solution, it is helpful to optimize the production process and improve the yield and yield of the product. According to actual tests, the yield and yield are improved by 5%; the quality of the ferrous sulfate solution is guaranteed to be stable, the production loss caused by quality problems is reduced, and the waste of raw materials is reduced. According to statistics, the consumption of raw materials is reduced by 10%. DETAILED DESCRIPTION

[0025] The present application is described in further detail below. It is necessary to point out that the following specific implementation methods are only used to further illustrate the present application and cannot be understood as limiting the scope of protection of the present application. Technicians in this field can make some non-essential improvements and adjustments to the present application based on the above application content.

[0026] Unless otherwise specified, the methods used in the present invention are conventional methods known to those skilled in the art, and the reagents and other materials used are commercially available products unless otherwise specified.

[0027] In the present invention

[0028] The conductivity of distilled water is ≤0.50mS / m, PH=5.0~7.5;

[0029] The preparation method of sulfur-phosphorus mixed acid is as follows: phosphoric acid, sulfuric acid and water are mixed to obtain sulfur-phosphorus mixed acid, wherein the mass ratio of phosphoric acid, sulfuric acid and water is 1:1:3;

[0030] The concentration of the methyl orange indicator is 5 g / L; the concentration of the sodium diphenylamine sulfonate indicator is 5 g / L;

[0031] The sodium hydroxide standard solution: the titer is 0.02434 g / mL; the potassium dichromate standard solution: the titer is 0.005585 g / mL;

[0032] The time for the first group of cuboids to surround the sprayed silk film was 5 minutes; the time for the second group of cuboids to surround the sprayed silk film was 8 minutes; and the time for the third group of cuboids to surround the sprayed silk film was 11 minutes.

[0033] Example 1

[0034] Preparation of carbon dioxide pellets: (i) Preparation of pelleting liquid: 3 parts of casein, 3 parts of gum arabic, 10 parts of charcoal powder, 1 part of tannic acid and 6 parts of pectin are placed in a wall-breaking machine, and the wall-breaking treatment is carried out for 5 minutes to obtain a mixed powder; the mixed powder is mixed with 40 parts of pure water, added to a centrifugal stirrer, and centrifugal stirring is carried out at 600r / min for 15 minutes to obtain a pelleting liquid; (ii) solid carbon dioxide is divided into rectangular blocks with a length, width and height of 2×3×1.5nm; (iii) the pelleting liquid is added into a high-voltage electrospinning device, the rectangular blocks are divided into three equal parts, and then the three groups of rectangular blocks are surrounded by spraying silk film to obtain carbon dioxide pellets, which are stored at low temperature at -60°C for use;

[0035] Preparation of sterile environment agent: Add 5 parts of sodium hypochlorite to 10 parts of pure water and stir for 30 minutes to obtain a sodium hypochlorite solution;

[0036] Glutaraldehyde was added at the 10th minute of stirring, and then 6 parts of hydrogen peroxide were added at the 25th minute of stirring, and the mixture was fully mixed to obtain a preformed liquid;

[0037] The pre-made solution was stored at 2°C and 8 portions of carbon dioxide pellets were added 20 minutes before use to obtain a sterile environment agent;

[0038] Place the sterilant inside the experimental box and start measuring the acidity of the ferrous sulfate solution after 5 minutes;

[0039] Determine the acidity of ferrous sulfate solution: take 1 mL of ferrous sulfate solution in a conical flask, add 30 mL of distilled water to purge the cup wall, add 2 drops of methyl orange indicator, the liquid is orange-red at this time, use sodium hydroxide standard solution to titrate until yellow, this is the titration end point, calculate its acidity by the sodium hydroxide consumption (PHB = V1 × TH2SO4 / NaOH) / Vtake);

[0040] Determination of ferrous iron content: Add 10% sulfuric acid mixed acid into a conical flask, then add 6 drops of sodium diphenylamine sulfonate indicator. At this time, the solution is pink. Use potassium dichromate standard solution to titrate until it turns purple. This is the titration end point. Calculate the ferrous iron content by the potassium dichromate consumption (w = V1×TFe / K2Cr2O7) / Vtake).

[0041] Example 2

[0042] Preparation of carbon dioxide pellets: (i) Preparation of pelleting liquid: 5 parts of casein, 6 parts of gum arabic, 15 parts of charcoal powder, 2 parts of tannic acid and 10 parts of pectin are placed in a wall-breaking machine, and the wall-breaking treatment is carried out for 6 minutes to obtain a mixed powder; the mixed powder is mixed with 45 parts of pure water, added to a centrifugal stirrer, and centrifugal stirring is carried out at 800r / min for 18 minutes to obtain a pelleting liquid; (ii) solid carbon dioxide is divided into rectangular blocks with a length, width and height of 2×3×1.5nm; (iii) the pelleting liquid is added into a high-voltage electrospinning device, the rectangular blocks are divided into three equal parts, and then the three groups of rectangular blocks are surrounded by spraying silk film to obtain carbon dioxide pellets, which are stored at low temperature at -60°C for use;

[0043] Preparation of sterile environment agent: Add 8 parts of sodium hypochlorite to 20 parts of pure water and stir for 35 minutes to obtain sodium hypochlorite solution;

[0044] Glutaraldehyde was added at the 10th minute of stirring, and then 8 parts of hydrogen peroxide were added at the 25th minute of stirring, and the mixture was fully mixed to obtain a preformed liquid;

[0045] The pre-made solution was stored at 3°C ​​and 12 portions of carbon dioxide pellets were added 25 minutes before use to obtain a sterile environment agent;

[0046] Place the sterilant inside the experimental box and start measuring the acidity of the ferrous sulfate solution after 10 minutes;

[0047] Determine the acidity of ferrous sulfate solution: take 3 mL of ferrous sulfate solution in a conical flask, add 30 mL of distilled water to purge the cup wall, add 3 drops of methyl orange indicator, the liquid is orange-red at this time, use sodium hydroxide standard solution to titrate until yellow, this is the titration end point, calculate its acidity by the sodium hydroxide consumption (PHB = V1 × TH2SO4 / NaOH) / Vtake);

[0048] Determination of ferrous iron content: Add 15 mL of sulfuric acid and phosphoric acid mixture into a conical flask, then add 7 drops of sodium diphenylamine sulfonate indicator. The solution is pink at this time. Use potassium dichromate standard solution to titrate until it turns purple. This is the titration end point. Calculate the ferrous iron content by the potassium dichromate consumption (w = V1×TFe / K2Cr2O7) / Vtake).

[0049] Example 3

[0050] Preparation of carbon dioxide pellets: (i) Preparation of pelleting liquid: 8 parts of casein, 8 parts of gum arabic, 20 parts of charcoal powder, 3 parts of tannic acid and 12 parts of pectin are placed in a wall-breaking machine, and the wall-breaking treatment is carried out for 8 minutes to obtain a mixed powder; the mixed powder is mixed with 50 parts of pure water, added to a centrifugal stirrer, and centrifugal stirring is carried out at 1000r / min for 30 minutes to obtain a pelleting liquid; (ii) solid carbon dioxide is divided into rectangular blocks with a length, width and height of 2×3×1.5nm; (iii) the pelleting liquid is added into a high-voltage electrospinning device, the rectangular blocks are divided into three equal parts, and then the three groups of rectangular blocks are surrounded by spraying silk film to obtain carbon dioxide pellets, which are stored at low temperature at -60°C for use;

[0051] Preparation of sterile environment agent: Add 10 parts of sodium hypochlorite to 25 parts of pure water and stir for 45 minutes to obtain a sodium hypochlorite solution;

[0052] Glutaraldehyde was added at the 10th minute of stirring, and then 10 parts of hydrogen peroxide were added at the 25th minute of stirring, and the mixture was fully mixed to obtain a preformed liquid;

[0053] The pre-made solution was stored at 5°C and 16 portions of carbon dioxide pellets were added 30 minutes before use to obtain a sterile environment agent;

[0054] Place the sterilant inside the test chamber and start measuring the acidity of the ferrous sulfate solution after 15 minutes;

[0055] Determine the acidity of ferrous sulfate solution: take 5 mL of ferrous sulfate solution in a conical flask, add 30 mL of distilled water to purge the cup wall, add 2 drops of methyl orange indicator, the liquid is orange-red at this time, use sodium hydroxide standard solution to titrate until yellow, this is the titration end point, calculate its acidity by the sodium hydroxide consumption (PHB = V1 × TH2SO4 / NaOH) / Vtake);

[0056] Determination of ferrous iron content: Add 15 mL of sulfur-phosphorus mixed acid into a conical flask, then add 6 drops of sodium diphenylamine sulfonate indicator. The solution is pink at this time. Use potassium dichromate standard solution to titrate until it turns purple. This is the titration end point. Calculate the ferrous iron content by the potassium dichromate consumption (w = V1×TFe / K2Cr2O7) / Vtake).

[0057] Comparative Example 1

[0058] Preparation of carbon dioxide pellets: (i) Preparation of pelleting liquid: 6 parts of gum arabic, 15 parts of charcoal powder, 7 parts of tannic acid and 10 parts of pectin are placed in a wall breaking machine, and the wall breaking treatment is carried out for 6 minutes to obtain a mixed powder; the mixed powder is mixed with 45 parts of pure water, added to a centrifugal stirrer, and centrifugal stirring is carried out at 800r / min for 18 minutes to obtain a pelleting liquid; (ii) solid carbon dioxide is divided into rectangular blocks with a length, width and height of 2×3×1.5nm; (iii) the pelleting liquid is added into a high-voltage electrospinning device, the rectangular blocks are divided into three equal parts, and then the three groups of rectangular blocks are surrounded by spraying silk film to obtain carbon dioxide pellets, which are stored at low temperature at -60°C for use;

[0059] Preparation of sterile environment agent: Add 8 parts of sodium hypochlorite to 20 parts of pure water and stir for 35 minutes to obtain sodium hypochlorite solution;

[0060] Glutaraldehyde was added at the 10th minute of stirring, and then 8 parts of hydrogen peroxide were added at the 25th minute of stirring, and the mixture was fully mixed to obtain a preformed liquid;

[0061] The pre-made solution was stored at 3°C ​​and 12 portions of carbon dioxide pellets were added 25 minutes before use to obtain a sterile environment agent;

[0062] Place the sterilant inside the experimental box and start measuring the acidity of the ferrous sulfate solution after 10 minutes;

[0063] Determine the acidity of ferrous sulfate solution: take 3 mL of ferrous sulfate solution in a conical flask, add 30 mL of distilled water to purge the cup wall, add 3 drops of methyl orange indicator, the liquid is orange-red at this time, use sodium hydroxide standard solution to titrate until yellow, this is the titration end point, calculate its acidity by the sodium hydroxide consumption (PHB = V1 × TH2SO4 / NaOH) / Vtake);

[0064] Determination of ferrous iron content: Add 15 mL of sulfuric acid and phosphoric acid mixture into a conical flask, then add 7 drops of sodium diphenylamine sulfonate indicator. The solution is pink at this time. Use potassium dichromate standard solution to titrate until it turns purple. This is the titration end point. Calculate the ferrous iron content by the potassium dichromate consumption (w = V1×TFe / K2Cr2O7) / Vtake).

[0065] Comparative Example 2

[0066] Preparation of carbon dioxide pellets: (i) Preparation of pelleting liquid: 7 parts of casein, 6 parts of gum arabic, 15 parts of charcoal powder and 10 parts of pectin are placed in a wall breaking machine, and the wall breaking treatment is carried out for 6 minutes to obtain a mixed powder; the mixed powder is mixed with 45 parts of pure water, added to a centrifugal stirrer, and centrifugal stirring is carried out at 800r / min for 18 minutes to obtain a pelleting liquid; (ii) solid carbon dioxide is divided into rectangular blocks with a length, width and height of 2×3×1.5nm; (iii) the pelleting liquid is added into a high-voltage electrospinning device, the rectangular blocks are divided into three equal parts, and then the three groups of rectangular blocks are surrounded by spraying silk film to obtain carbon dioxide pellets, which are stored at low temperature at -60°C for use;

[0067] Preparation of sterile environment agent: Add 8 parts of sodium hypochlorite to 20 parts of pure water and stir for 35 minutes to obtain sodium hypochlorite solution;

[0068] Glutaraldehyde was added at the 10th minute of stirring, and then 8 parts of hydrogen peroxide were added at the 25th minute of stirring, and the mixture was fully mixed to obtain a preformed liquid;

[0069] The pre-made solution was stored at 3°C ​​and 12 portions of carbon dioxide pellets were added 25 minutes before use to obtain a sterile environment agent;

[0070] Place the sterilant inside the experimental box and start measuring the acidity of the ferrous sulfate solution after 10 minutes;

[0071] Determine the acidity of ferrous sulfate solution: take 3 mL of ferrous sulfate solution in a conical flask, add 30 mL of distilled water to purge the cup wall, add 3 drops of methyl orange indicator, the liquid is orange-red at this time, use sodium hydroxide standard solution to titrate until yellow, this is the titration end point, calculate its acidity by the sodium hydroxide consumption (PHB = V1 × TH2SO4 / NaOH) / Vtake);

[0072] Determination of ferrous iron content: Add 15 mL of sulfuric acid and phosphoric acid mixture into a conical flask, then add 7 drops of sodium diphenylamine sulfonate indicator. The solution is pink at this time. Use potassium dichromate standard solution to titrate until it turns purple. This is the titration end point. Calculate the ferrous iron content by the potassium dichromate consumption (w = V1×TFe / K2Cr2O7) / Vtake).

[0073] Comparative Example 3

[0074] Preparation of carbon dioxide-coated pellets: (i) dividing solid carbon dioxide into rectangular blocks with a length, width and height of 2×3×1.5 nm; (ii) adding a water-soluble resin solution into a high-voltage electrospinning device, dividing the rectangular blocks into three equal parts, and then surrounding-spraying a silk film on the three groups of rectangular blocks to obtain carbon dioxide-coated pellets, which are stored at -60°C for future use;

[0075] Preparation of sterile environment agent: Add 8 parts of sodium hypochlorite to 20 parts of pure water and stir for 35 minutes to obtain sodium hypochlorite solution;

[0076] Glutaraldehyde was added at the 10th minute of stirring, and then 8 parts of hydrogen peroxide were added at the 25th minute of stirring, and the mixture was fully mixed to obtain a preformed liquid;

[0077] The pre-made solution was stored at 3°C ​​and 12 portions of carbon dioxide pellets were added 25 minutes before use to obtain a sterile environment agent;

[0078] Place the sterilant inside the experimental box and start measuring the acidity of the ferrous sulfate solution after 10 minutes;

[0079] Determine the acidity of ferrous sulfate solution: take 3 mL of ferrous sulfate solution in a conical flask, add 30 mL of distilled water to purge the cup wall, add 3 drops of methyl orange indicator, the liquid is orange-red at this time, use sodium hydroxide standard solution to titrate until yellow, this is the titration end point, calculate its acidity by the sodium hydroxide consumption (PHB = V1 × TH2SO4 / NaOH) / Vtake);

[0080] Determination of ferrous iron content: Add 15 mL of sulfuric acid and phosphoric acid mixture into a conical flask, then add 7 drops of sodium diphenylamine sulfonate indicator. The solution is pink at this time. Use potassium dichromate standard solution to titrate until it turns purple. This is the titration end point. Calculate the ferrous iron content by the potassium dichromate consumption (w = V1×TFe / K2Cr2O7) / Vtake).

[0081] Comparative Example 4

[0082] Inside the experimental box, measure the acidity of the ferrous sulfate solution;

[0083] Determine the acidity of ferrous sulfate solution: take 3 mL of ferrous sulfate solution in a conical flask, add 30 mL of distilled water to purge the cup wall, add 3 drops of methyl orange indicator, the liquid is orange-red at this time, use sodium hydroxide standard solution to titrate until yellow, this is the titration end point, calculate its acidity by the sodium hydroxide consumption (PHB = V1 × TH2SO4 / NaOH) / Vtake);

[0084] Determination of ferrous iron content: Add 15 mL of sulfuric acid and phosphoric acid mixture into a conical flask, then add 7 drops of sodium diphenylamine sulfonate indicator. The solution is pink at this time. Use potassium dichromate standard solution to titrate until it turns purple. This is the titration end point. Calculate the ferrous iron content by the potassium dichromate consumption (w = V1×TFe / K2Cr2O7) / Vtake).

[0085] Performance Testing

[0086] Calculate the sodium hydroxide consumption and potassium dichromate consumption in Examples 1-3 and Comparative Examples 1-3 respectively.

[0087] Use a counter to record the duration of acidity determination and ferrous iron content determination

[0088] The calculation results are as follows

[0089] project Sodium hydroxide consumption Potassium dichromate consumption Acidity measurement time Determination time of ferrous iron content Example 1 4.80g / l 44.21g / l 10 / min 20 / min Example 2 2.45g / l 37.83g / l 8 / min 15 / min Example 3 3.67g / l 45.49g / l 9 / min 21 / min Comparative Example 1 6.02g / l 53.14g / l 11 / min 27 / min Comparative Example 2 9.66g / l 56.97g / l 14 / min 30 / min Comparative Example 3 14.80g / l 63.35g / l 18 / min 35 / min

[0090] It can be seen from the above table that the consumption of sodium hydroxide and potassium dichromate has a significant relationship with the carbon dioxide pellets used. At the same time, the carbon dioxide pellets have an obvious relationship with the acidity determination time and the divalent iron content determination time. Adjusting the proportion of carbon dioxide pellets can affect the consumption of sodium hydroxide and potassium dichromate and the acidity determination time and the divalent iron content determination time.

[0091] The above-mentioned embodiments only express several implementation methods of the present invention, and the description thereof is relatively specific and detailed, but it cannot be understood as limiting the scope of the present invention. It should be pointed out that, for ordinary technicians in this field, several variations and improvements can be made without departing from the concept of the present invention, which all belong to the protection scope of the present invention.

Claims

1. A method for continuously measuring the acidity and ferrous iron content of ferrous sulfate solution, characterized in that: The following steps are involved: Step S1, preparing carbon dioxide pellets: (i) preparing pelleting liquid: placing casein, gum arabic, charcoal powder, tannic acid and pectin in a wall breaking machine, performing wall breaking treatment for 5-8 minutes, and obtaining a mixed powder; mixing the mixed powder with pure water, adding the mixture into a centrifugal stirrer, performing centrifugal stirring treatment, stirring at 600-1000r / min for 15-30 minutes, and obtaining a pelleting liquid; (ii) dividing solid carbon dioxide into rectangular blocks with a length, width and height of 2×3×1.5nm; (iii) adding the pelleting liquid into a high-voltage electrospinning device, dividing the rectangular blocks into three equal parts, and then surrounding the three groups of rectangular blocks with spraying silk film to obtain carbon dioxide pellets, which are stored at low temperature at -60°C for standby use. Step S2, preparing a sterile environment agent: adding sodium hypochlorite to pure water, stirring for 30-45 minutes, to obtain a sodium hypochlorite solution; Glutaraldehyde was added at the 10th minute of stirring, and then hydrogen peroxide was added at the 25th minute of stirring, and the mixture was fully mixed to obtain a preformed liquid; The pre-made solution was stored at 2-5°C and carbon dioxide was added to the pellets 20-30 minutes before use to obtain a sterile environment agent; Step S3, placing the sterilant inside the test box, and starting to measure the acidity of the ferrous sulfate solution after 5-15 minutes; Step S4, determining the acidity of the ferrous sulfate solution: taking a volume of 1-5 mL of ferrous sulfate solution in a conical flask, adding 20-30 mL of distilled water to purge the cup wall, adding 2-3 drops of methyl orange indicator, at this time the liquid is orange-red, using a sodium hydroxide standard solution to titrate to yellow, this is the titration end point, and the acidity is calculated by the sodium hydroxide consumption (PHB = V1 × TH2SO4 / NaOH) / Vtake); The specific reaction equation is as follows: H2SO4+2NaOH=Na2SO4+2H2O; Step S5, determining the ferrous iron content: adding 10-15 mL of sulfur-phosphorus mixed acid into a conical flask, and then dropping 6-7 drops of sodium diphenylamine sulfonate indicator, the solution is now pink, and titrated with potassium dichromate standard solution until it turns purple, which is the titration end point, and calculating the ferrous iron content by the potassium dichromate consumption (w=V1×TFe / K2Cr2O7) / Vtake); The specific reaction equation is as follows: K2Cr2O7+6FeSO4+7H2SO4=3Fe2(SO4)3+Cr2(SO4)3+K2SO4+7H2O.

2. A method for continuously measuring the acidity and ferrous iron content of ferrous sulfate solution according to claim 1, characterized in that: The conductivity of the distilled water is ≤0.50 mS / m, and the pH is 5.0-7.

5.

3. A method for continuously measuring the acidity and ferrous iron content of ferrous sulfate solution according to claim 1, characterized in that: The preparation method of the sulfur-phosphorus mixed acid is: mixing phosphoric acid, sulfuric acid and water to obtain the sulfur-phosphorus mixed acid, wherein the mass ratio of the phosphoric acid, sulfuric acid and water is 1:1:

3.

4. A method for continuously measuring the acidity and ferrous iron content of ferrous sulfate solution according to claim 1, characterized in that: The concentration of the methyl orange indicator is 5 g / L; the concentration of the sodium diphenylamine sulfonate indicator is 5 g / L.

5. A method for continuously measuring the acidity and ferrous iron content of ferrous sulfate solution according to claim 1, characterized in that: The sodium hydroxide standard solution has a titer of 0.02434 g / mL; the potassium dichromate standard solution has a titer of 0.005585 g / mL.

6. A method for continuously measuring the acidity and ferrous iron content of ferrous sulfate solution according to claim 1, characterized in that: The time for the first group of cuboids to surround the sprayed silk film is 5 minutes; the time for the second group of cuboids to surround the sprayed silk film is 8 minutes; and the time for the third group of cuboids to surround the sprayed silk film is 11 minutes.

7. A method for continuously measuring the acidity and ferrous iron content of ferrous sulfate solution according to claim 1, characterized in that: The raw materials for preparing the pill-packing liquid include, by weight: 3-8 parts of casein, 3-8 parts of gum arabic, 10-20 parts of charcoal powder, 1-3 parts of tannic acid, 6-12 parts of pectin and 40-50 parts of pure water.

8. A method for continuously measuring the acidity and ferrous iron content of ferrous sulfate solution according to claim 1, characterized in that: The raw materials for preparing the sterile environment agent include, by weight: 5-10 parts of sodium hypochlorite, 10-25 parts of pure water, 6-10 parts of hydrogen peroxide and 8-16 parts of carbon dioxide pellets.