Safe treatment method of scrapped perchloric acid

Abstract

The invention relates to the technical field of hazardous waste treatment, in particular to a safe treatment method of scrapped perchloric acid, which comprises the following steps: step 1, taking a certain amount of water, slowly dropwise adding perchloric acid into the water to obtain a pretreatment solution A, and pretreating the perchloric acid to reduce the danger and oxidability of the perchloric acid; step 2, slowly dropwise adding a sodium hydroxide solution into the pretreatment solution A, neutralizing perchloric acid to generate sodium perchlorate to obtain a mixed solution B, and reducing the risk of high corrosivity of perchloric acid. According to the safe treatment method for the scrapped perchloric acid, provided by the invention, the safe treatment method for the scrapped perchloric acid is a safe and stable treatment method for the scrapped perchloric acid, the safe treatment of the perchloric acid is realized by controlling a reaction system medicament and through a multi-stage reaction process, and three wastes of the system are effectively collected and treated in the whole reaction process; therefore, the operation environment is safe when the perchloric acid is treated.

Description

Technical Field

[0001] The invention relates to the technical field of hazardous waste treatment, and in particular to a safe treatment method for waste perchloric acid. Background Art

[0002] Perchloric acid is an inorganic compound with the chemical formula HClO4. It is the first of the six inorganic strong acids and the hydrate of the highest valence oxide of chlorine. It is a colorless, transparent, fuming liquid. Perchloric acid is the most acidic among inorganic oxygen-containing acids. It can support combustion, is highly corrosive and irritating, and can cause burns to the human body. It is used in industry for the preparation of perchlorates, purification of artificial diamonds, film manufacturing, pharmaceutical industry, electropolishing industry, production of grinding wheels, removal of carbon particle impurities, and can also be used as an oxidant. Perchloric acid is also widely used in laboratories. Perchloric acid is often used as an oxidant in laboratories to oxidize metals, organic compounds, and evaluate the oxidizability of substances. In analytical chemistry, perchloric acid can be used as an acid to treat samples and is widely used in sample pretreatment, digestion, and dissolution. Therefore, a large amount of scrapped reagent perchloric acid generated by universities and laboratories is relatively dangerous.

[0003] After perchloric acid is discharged, it is easy to form perchlorate with alkaline substances. － It has toxicological characteristics of interfering with the absorption of iodine in the human body and inhibiting the thyroid gland's ability to regulate hormone secretion and metabolism, and may cause red blood cell damage and liver and kidney damage to a certain extent. The related environmental pollution and human health and safety issues have attracted great attention from researchers. Effectively removing it based on a deep understanding of its environmental chemical characteristics and hazards has been the focus and difficulty of research in recent years. And because perchloric acid is highly active, it is difficult to treat this type of waste, there are major safety hazards in the treatment process, and it has a serious impact on the ecological environment and human health. There is currently no treatment method that can be used as a reference. Therefore, the process methods of dilution pretreatment and multi-stage reaction were studied to treat this type of hazardous waste. Summary of the invention

[0004] The object of the present invention is to solve the problems existing in the prior art of treating waste perchloric acid and to propose a safe treatment method for waste perchloric acid.

[0005] In order to achieve the above object, the present invention adopts the following technical solutions: A safe treatment method for waste perchloric acid comprises the following steps: Step 1: Take a certain amount of water, slowly add perchloric acid thereto, and obtain pre-treated solution A, wherein the perchloric acid is pre-treated to reduce its hazard and oxidizing property; Step 2: slowly drop sodium hydroxide solution into the pretreatment solution A to neutralize the perchloric acid to generate sodium perchlorate to obtain a mixed solution B, thereby reducing the risk of high corrosiveness of perchloric acid; Step 3, adding titanium trichloride waste liquid to mixed solution B, stirring for a period of time, and then dropping alanine solution therein to catalyze the reaction to obtain mixed solution C, and finally heating the mixed solution C; Step 4: After the reaction is complete, slowly add sodium hydroxide solution to the mixed solution C to adjust the pH value to 8.0-9.0 to obtain a mixed solution D; Step 5. The reactions from step 1 to step 4 are all carried out in a fume hood; Step 6: After the mixed liquor D is filtered through a plate and frame filter, the filtrate is reused after evaporation, desalination and biochemical treatment, and the filter residue is collected for resource recovery.

[0006] As a further description of the above technical solution: In the step 1, the ratio of recycled water to perchloric acid is 10:1, and perchloric acid is slowly added dropwise into the water.

[0007] As a further description of the above technical solution: When the concentration of sodium hydroxide in step 2 is 15%-20% and the pH value of the reaction solution is 7.0-8.0, the addition of sodium hydroxide solution is stopped.

[0008] As a further description of the above technical solution: The titanium trichloride waste liquid in step 3 is a titanium trichloride solution produced in the process of determining the total iron content in iron ore, and the titanium trichloride content is 15%. 1%-5% hydrochloric acid is added to the titanium trichloride solution to ensure that the titanium trichloride solution is acidic.

[0009] As a further description of the above technical solution: In step 3, the concentration of alanine solution is 30%-40%, and the reaction temperature is controlled at 50-60°C.

[0010] As a further description of the above technical solution: The filter residue produced in step 5 is titanium dioxide, which can be used as a resource. The waste liquid produces sodium chloride as a byproduct after evaporation. The obtained evaporated filtrate meets the reuse requirements after biochemical treatment.

[0011] In summary, due to the adoption of the above technical solution, the beneficial effects of the present invention are: 1. In the present invention, the goal of treating waste with waste is achieved by utilizing the effective components in hazardous waste.

[0012] 2. In the present invention, perchlorate is highly stable and it is extremely difficult for general reducing agents to destroy its structure. Heating destruction requires 100°C or even higher temperatures. The present invention uses titanium trichloride waste liquid and catalyst alanine to reduce perchlorate to chloride ions at 50°C, and finally prepares sodium chloride as a resource.

[0013] 3. In the present invention, the filter residue produced in the process of treating perchloric acid is titanium dioxide, and the byproduct is sodium chloride. The biochemical effluent can be used as recycled water for perchloric acid pretreatment, which not only treats perchloric acid but also prepares titanium dioxide and sodium chloride, turning waste into treasure.

[0014] 4. In the present invention, the waste titanium trichloride solution and catalyst alanine used in the treatment process are cheap and easily available, which greatly reduces the treatment cost. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 The following is a comparison table of perchlorate ion detection data of four implementation cases in a specific embodiment of the present invention. DETAILED DESCRIPTION

[0016] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0017] See also Figure 1 The present invention provides a technical solution: a safe treatment method for waste perchloric acid, comprising the following steps: The first step is to take a certain amount of water and slowly drop perchloric acid into it to obtain a pretreatment solution A. The perchloric acid is pretreated to reduce its hazard and oxidizing properties. In step 1, the ratio of the recycled water to the perchloric acid is 10:1, and the perchloric acid is slowly dropped into the water; Step 2: slowly drop a 15%-20% sodium hydroxide solution into the pretreatment solution A to neutralize the perchloric acid to generate sodium perchlorate, thereby obtaining a mixed solution B, thereby reducing the risk of high corrosiveness of perchloric acid. When the pH value of the reaction solution reaches 7.0-8.0, stop adding the sodium hydroxide solution. The third step is to add titanium trichloride waste liquid to the mixed solution B, stir for a period of time, and then dropwise add alanine solution with a concentration of 30%-40% thereto to catalyze the reaction to obtain a mixed solution C, and finally heat the mixed solution C, and the reaction temperature is controlled at 50-60° C. In this step, the titanium trichloride waste liquid is a titanium trichloride solution produced in the process of determining the total iron content in the iron ore, and the titanium trichloride content is 15%. 1%-5% hydrochloric acid is added to the titanium trichloride solution to ensure that the titanium trichloride solution is acidic; Step 4: After the reaction is complete, slowly add sodium hydroxide solution to the mixed solution C to adjust the pH value to 8.0-9.0 to obtain a mixed solution D; The reactions in step 5 and steps 1 to 4 were all carried out in a fume hood; Step 6. After the mixed liquor D is filtered through a plate and frame filter, the filtrate is reused after evaporation desalination and biochemical treatment, and the filter residue is collected for resource utilization. The filter residue produced in this step is titanium dioxide, which can be recycled. The waste liquid produces sodium chloride as a by-product after evaporation. The obtained evaporated filtrate meets the reuse requirements after biochemical treatment.

[0018] Specifically, the present invention effectively utilizes the effective components in hazardous wastes to achieve the goal of treating waste with waste, and the liquid and solid components generated in the treatment process are effectively disposed of and recycled, which has significant economic and environmental benefits.

[0019] The titanium trichloride waste liquid in the present invention has strong reducing properties, can slowly reduce perchlorate, and can effectively treat perchloric acid. The absorption peak of the titanium trichloride solution is found at 480nm through ultraviolet absorption spectrum. The position of the peak indicates that the titanium trichloride exists in the solution in the form of (HO)Ti(OH2)5 2+ , the reduction mechanism of sodium perchlorate is as follows: 8(HO)Ti(OH2)5 2+ +ClO 4- =8TiO2+Cl - +16H + +36H2O The present invention uses alanine as a catalyst, which not only improves the catalytic reaction efficiency but also broadens the scope of application. When alanine is not added, the optimum pH for the titanium trichloride reduction reaction of perchlorate is 2.0. When the pH value is from 1.2 to 2.0, the reduction rate is significantly improved. In the pH range of >2.0, titanium dioxide precipitates are formed and the reduction is significantly inhibited. When alanine is added, sodium perchlorate can be reduced even when the pH is close to neutral. The presence of alanine significantly improves the reduction efficiency of perchlorate. This is because alanine forms a complex with Ti(III), which reduces the precipitation of titanium dioxide in the pH range of 2.0 to 5.0, greatly improves the [Ti(III)] content in the solution, and further enhances the reduction efficiency of perchlorate.

[0020] The solution of the present invention is further described in detail below in conjunction with implementation cases.

[0021] The test sample was expired chemical reagent perchloric acid received by a hazardous waste enterprise.

[0022] Implementation Case 1 Take 10mL of perchloric acid and add it to 100mL of water, stir it thoroughly, mix it evenly, add 15% sodium hydroxide solution to the mixture, and stop adding after controlling the pH to 7.0. Then slowly add 200mL of expired and scrapped titanium trichloride solution produced by measuring the total iron content in iron ore, add 10mL of 1% hydrochloric acid, and then add 50mL of 30% alanine solution, stir it thoroughly, heat it to 50°C in an oil bath, and react for 3h. Then add 15% sodium hydroxide solution to adjust the pH value to 9.0, and filter to obtain titanium dioxide filter residue. The filtrate produces sodium chloride as a byproduct after evaporation. The filtrate after evaporation is tested for perchlorate content according to GB 5009.291-2023.

[0023] Implementation Case 2 Take 100mL of perchloric acid and add it to 1000mL of water, stir it thoroughly, mix it evenly, add 15% sodium hydroxide solution to the mixture, and stop adding it after controlling the pH to 7.0. Then slowly add 2000mL of expired and scrapped ferric chloride solution produced by measuring the total iron content in iron ore, add 100mL of 1% hydrochloric acid, and then add 500mL of 30% alanine solution and stir it thoroughly. Heat to 50°C in an oil bath and react for 3h. Then add 15% sodium hydroxide solution to adjust the pH to 9.0, filter, and obtain titanium dioxide filter residue. The filtrate produces sodium chloride as a byproduct after evaporation. After evaporation, the filtrate is tested for perchlorate content according to GB5009.291-2023.

[0024] Implementation Case 3 The difference from Example 1 is that 10 mL of 30% alanine solution is added, and the remaining addition amounts and proportions are the same.

[0025] Implementation Case 4 The difference from Example 1 is that 100 mL of 30% alanine solution is added, and the remaining addition amounts and proportions are the same.

[0026] In summary, please refer to Figure 1 As shown in the figure, from the results of implementation cases 1-2, it can be seen that the safe treatment method for waste perchloric acid provided by the present invention has a large treatment capacity and a good treatment effect. By comparing with implementation case 3, it can be seen that if the alanine solution is not added, the treatment effect is poor, and the perchlorate is not completely removed. The addition of alanine increases the soluble Ti and forms a multi-core titanium species TiOTiOH 3+ , which is conducive to the reduction of perchlorate. In contrast to Example 4, when an excessive amount of alanine solution was added, 5 mg / L of perchlorate was detected, and the perchlorate reduction kinetics was hindered. Therefore, excessive addition of alanine is unnecessary and disadvantageous.

[0027] The invention discloses a safe treatment method for waste perchloric acid, wherein 15% sodium hydroxide is added to convert titanium ions in the waste liquid into titanium dioxide precipitation, and the titanium dioxide product is filtered, washed, dried, and treated, and the dry basis purity is 98%, which meets the use requirements of industrial grade titanium dioxide. The treated filtrate is evaporated to produce a byproduct of sodium chloride, and after recrystallization, the dry basis purity is 99%, which meets the quality standard of industrial grade sodium chloride (greater than 98.5%). The filter residue produced in the process of treating perchloric acid is titanium dioxide, and the byproduct is sodium chloride. The invention not only treats perchloric acid but also prepares titanium dioxide and sodium chloride, turning waste into treasure.

[0028] The above description is only a preferred specific implementation manner of the present invention, but the protection scope of the present invention is not limited thereto. Any technician familiar with the technical field can make equivalent replacements or changes according to the technical scheme and inventive concept of the present invention within the technical scope disclosed by the present invention, which should be covered by the protection scope of the present invention.

Claims

1. A safe treatment method for waste perchloric acid, characterized in that: The following steps are involved: Step 1: Take a certain amount of water, slowly add perchloric acid thereto, and obtain pre-treated solution A, wherein the perchloric acid is pre-treated to reduce its hazard and oxidizing property; Step 2: slowly drop sodium hydroxide solution into the pretreatment solution A to neutralize the perchloric acid to generate sodium perchlorate to obtain a mixed solution B, thereby reducing the risk of high corrosiveness of perchloric acid; Step 3, adding titanium trichloride waste liquid to mixed solution B, stirring for a period of time, and then dropping alanine solution therein to catalyze the reaction to obtain mixed solution C, and finally heating the mixed solution C; Step 4: After the reaction is complete, slowly add sodium hydroxide solution to the mixed solution C to adjust the pH value to 8.0-9.0 to obtain a mixed solution D; Step 5. The reactions from step 1 to step 4 are all carried out in a fume hood; Step 6: After the mixed liquor D is filtered through a plate and frame filter, the filtrate is reused after evaporation, desalination and biochemical treatment, and the filter residue is collected for resource recovery.

2. A safe treatment method for waste perchloric acid according to claim 1, characterized in that: In the step 1, the ratio of recycled water to perchloric acid is 10:1, and perchloric acid is slowly added dropwise into the water.

3. A safe treatment method for waste perchloric acid according to claim 1, characterized in that: When the concentration of sodium hydroxide in step 2 is 15%-20% and the pH value of the reaction solution is 7.0-8.0, the addition of sodium hydroxide solution is stopped.

4. A safe treatment method for waste perchloric acid according to claim 1, characterized in that: The titanium trichloride waste liquid in step 3 is a titanium trichloride solution produced in the process of determining the total iron content in iron ore, and the titanium trichloride content is 15%. 1%-5% hydrochloric acid is added to the titanium trichloride solution to ensure that the titanium trichloride solution is acidic.

5. A safe treatment method for waste perchloric acid according to claim 1 or 4, characterized in that: In step 3, the concentration of alanine solution is 30%-40%, and the reaction temperature is controlled at 50-60°C.

6. The safe treatment method for waste perchloric acid according to claim 1, characterized in that: The filter residue produced in step 5 is titanium dioxide, which can be used as a resource. The waste liquid produces sodium chloride as a byproduct after evaporation. The obtained evaporated filtrate meets the reuse requirements after biochemical treatment.

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