Recycling method of zinc selenite waste

Abstract

The invention discloses a recycling method of zinc selenite waste, which belongs to the technical field of resource recycling, and comprises the following steps: (1) uniformly mixing selenium dioxide, the zinc selenite waste and water, and filtering to obtain a mixed solution; and (2) heating and stirring the mixed solution, adding the zinc selenite fine material into the mixed solution, adding zinc oxide to adjust the pH value to 2.5-4, reacting, filtering, washing with water until the pH value is 5-7, and drying to obtain the zinc selenite. Selenium dioxide, zinc selenite waste and water are uniformly mixed, then the mixed solution is heated, zinc selenite fine materials are added, zinc oxide is added to adjust the pH to be 2.5-4, reaction and washing are performed, the pH is 5-7, zinc selenite which is good in product stability and does not generate red selenium in the storage process is obtained, the selenium content of the zinc selenite is 40.7%-41.2%, the zinc content is 33.7%-34.2%, and the content of the zinc selenite is 33.7%-34.2%. A repose angle lt; and the average particle size is 75-150 [mu] m.

Description

Technical Field

[0001] The invention relates to the technical field of resource recycling and reuse, and in particular to a method for recycling zinc selenite waste. Background Art

[0002] Zinc selenite is an inorganic compound with a wide range of applications and specific chemical properties. Zinc selenite appears as a white crystalline powder. Zinc selenite can be melted into a yellow transparent liquid under heating conditions, and solidified into a white block with crystalline cracks after cooling; it will decompose at higher temperatures. Zinc selenite will decompose at high temperatures to produce selenium (Se) and other compounds.

[0003] At present, the preparation methods of zinc selenite include: CN101172584A uses selenous acid and zinc oxide to directly react to synthesize zinc selenite. This process has the advantages of simple equipment, large production capacity of a single set of equipment, and low production cost, but selenous acid is likely to remain in the product, and red selenium is easily reduced during drying, transportation, and storage, causing the zinc selenite product to turn red and be unusable. CN105236469A uses selenous acid and basic zinc salt (basic zinc sulfate or basic zinc chloride) for synthesis, which has the advantages of high process efficiency, few by-products, and good product stability, but produces CO during the reaction. 2 Gas, carbon dioxide causes greenhouse effect and environmental problems.

[0004] During the production and subsequent storage and processing of zinc selenite, a certain amount of waste with too fine particles or reduced to red will be generated, which affects the use. If the waste cannot be effectively treated, it will cause a waste of resources. Therefore, it is necessary to invent a method for treating the waste of zinc selenite. Several methods have been disclosed to achieve the purpose of recycling and treating defective zinc selenite or waste.

[0005] Patent CN112390232A discloses a method for recovering zinc selenite: zinc selenite defective products are stirred and mixed with water and sulfuric acid to form a mixture containing selenious acid, and then the zinc selenite defective products are calcined at high temperature and air is introduced to recover selenium and zinc in the form of selenium dioxide and zinc sulfate. The present invention is of great significance for comprehensive resource utilization, reducing production costs and preventing and controlling environmental pollution, but high-temperature calcination is required to decompose selenious acid during the recovery process, resulting in increased energy consumption.

[0006] Patent CN113753865A discloses a method for preparing sodium selenite from inferior zinc selenite, which comprises mixing inferior zinc selenite with water, adding sodium hydroxide to adjust the pH of the solution, filtering and separating to obtain a filtrate and zinc hydroxide; then adding selenium dioxide to the filtrate, heating, evaporating and filtering to obtain sodium selenite. The yield of zinc hydroxide and sodium selenite products prepared by this method is high, the utilization rate of raw materials is high, the source of raw materials is simple, and there is no need to react under pressure. The operation is simple, the process is short, the cost is low, it is safe, environmentally friendly, and suitable for industrial application; the invention requires heating to evaporate the solution, which is time-consuming and energy-intensive.

[0007] In view of this, this application is filed. Summary of the invention

[0008] The purpose of the present invention is to overcome the shortcomings of the prior art and provide a method for recycling zinc selenite waste, thereby obtaining zinc selenite with good product stability and no red selenium generated during storage. The zinc selenite has a selenium content of 40.7% to 41.2%, a zinc content of 33.7% to 34.2%, an angle of repose of less than 42°, and an average particle size of 75 μm to 150 μm.

[0009] To achieve the above object, the technical solution adopted by the present invention is:

[0010] A method for recycling zinc selenite waste comprises the following steps:

[0011] (1) mixing selenium dioxide, zinc selenite waste and water uniformly, filtering and obtaining a mixed solution;

[0012] (2) heating and stirring the mixed solution, adding zinc selenite fine material to the mixed solution, and then adding zinc oxide to adjust the pH to 2.5-4, reacting, filtering, washing with water to a pH of 5-7, and drying to obtain zinc selenite.

[0013] The invention comprises the following steps: uniformly mixing selenium dioxide, zinc selenite waste and water, then heating the mixed solution, adding zinc selenite fine material, adding zinc oxide to adjust the pH value to 2.5-4, reacting, and washing with water to adjust the pH value to 5-7, thereby obtaining zinc selenite with good product stability and no red selenium generated during storage. The zinc selenite has a selenium content of 40.7%-41.2%, a zinc content of 33.7%-34.2%, an angle of repose of less than 42 degrees, and an average particle size of 75 μm-150 μm.

[0014] The recycling method of the invention can effectively recycle zinc selenite waste to prepare qualified zinc selenite products. The process is simple, the flow is short, the energy consumption is low, and the environment is friendly. The utilization rate of zinc selenite waste is high, and all of the waste can be recycled and utilized, and the method has broad application prospects.

[0015] The inventors of the present invention have found that the preparation parameters of the recycling method have a significant impact on the performance of zinc selenite. By controlling the preparation parameters within the scope of the present invention, zinc selenite with a selenium content of 40.7% to 41.2%, a zinc content of 33.7% to 34.2%, an angle of repose of less than 42°, and an average particle size of 75μm to 150μm is prepared.

[0016] Zinc oxide is added to control the pH to 2.5-4, the product has good stability, and zinc selenite will not produce red selenium during storage. If the pH is too low or too low, zinc selenite with expected performance cannot be obtained.

[0017] It should be noted that the zinc selenite waste described in the present invention is reddish zinc selenite.

[0018] The zinc selenite fine material refers to zinc selenite with an average particle size of ≤75 μm.

[0019] As a preferred embodiment of the present invention, the solid-to-liquid ratio of the selenium dioxide, zinc selenite waste and water is (200-300) g: (10-35) g: 3.3L.

[0020] As a preferred embodiment of the present invention, the solid-liquid ratio of the zinc selenite fine material to water is (25-40):3.3L.

[0021] As a preferred embodiment of the present invention, the addition rate of the zinc selenite fine material is (1-4)×(x / 3.3) g / min, where x is the volume of water in step (1).

[0022] As a preferred embodiment of the present invention, the addition rate of zinc oxide is 1 to 4×(x / 3.3) g / min, where x is the volume of water in step (1).

[0023] As a preferred embodiment of the present invention, the reaction temperature is 60-80° C., and the reaction time is 1-2 h.

[0024] As a preferred embodiment of the present invention, the stirring rate is 300-400 rpm.

[0025] As a preferred embodiment of the present invention, the heating temperature is 60-80°C.

[0026] As a preferred embodiment of the present invention, the drying temperature is 100-110° C., and the drying time is 16-24 hours.

[0027] As a preferred embodiment of the present invention, the zinc selenite has a selenium content of 40.7% to 41.2%, a zinc content of 33.7% to 34.2%, an angle of repose <42°, and an average particle size of 75 μm to 150 μm.

[0028] The beneficial effects of the present invention are as follows: (1) The present invention uniformly mixes selenium dioxide, zinc selenite waste and water, then heats the mixed solution, adds zinc selenite fine material, adds zinc oxide to adjust the pH to 2.5-4, reacts, and washes with water to a pH of 5-7, thereby obtaining zinc selenite with good product stability and no red selenium generated during storage. The zinc selenite has a selenium content of 40.7%-41.2%, a zinc content of 33.7%-34.2%, an angle of repose <42°, and an average particle size of 75μm-150μm. (2) The recycling method of the present invention effectively recycles zinc selenite waste to prepare qualified zinc selenite products. The process is simple, the process is short, the energy consumption is low, and the environment is friendly. The utilization rate of zinc selenite waste is high, and all of the waste can be recycled, which has a wide range of application prospects. DETAILED DESCRIPTION

[0029] In order to make the purpose, technical solutions and advantages of the embodiments of the present application clearer, the technical solutions in the embodiments of the present application are described clearly and completely below. Obviously, the described embodiments are part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present application.

[0030] In the present application, the technical features described in an open manner include closed technical solutions composed of the listed features, and also include open technical solutions containing the listed features.

[0031] In this application, when it comes to numerical ranges, unless otherwise specified, the above numerical ranges are deemed to be continuous and include the minimum and maximum values ​​of the range, as well as each value between such minimum and maximum values. Further, when a range refers to an integer, each integer between the minimum and maximum values ​​of the range is included. In addition, when multiple ranges are provided to describe features or characteristics, the ranges can be merged. In other words, unless otherwise specified, all ranges disclosed herein should be understood to include any and all subranges included therein.

[0032] In the present application, there is no particular limitation on the specific dispersion and stirring treatment methods.

[0033] Unless otherwise specified, the components, raw materials or instruments used in the embodiments and comparative examples of the present invention are all commercially available raw materials or instruments, and the components and raw materials used in each parallel experiment are all of the same kind.

[0034] In addition, the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" and "second" may explicitly or implicitly include at least one of the features. In the description of the present invention, the meaning of "plurality" is at least two, such as two, three, etc., unless otherwise clearly and specifically defined.

[0035] Example 1

[0036] A method for recycling zinc selenite waste comprises the following steps:

[0037] (1) 250 g of selenium dioxide, 10 g of zinc selenite waste, and 3.3 L of water were mixed and filtered to obtain a mixed solution;

[0038] (2) The mixed solution was heated to 60° C. and stirred at 300 rpm, 40 g of zinc selenite fine material was added to the mixed solution at a rate of 1 g / min, and zinc oxide was added at a rate of 1 g / min to adjust the pH to 2.5, reacted at 60° C. for 1 h, filtered, washed with water to a pH of 5, and dried in an oven at 100° C. for 16 h to obtain zinc selenite.

[0039] The zinc selenite waste material is reddish zinc selenite. The zinc selenite fine material refers to zinc selenite with an average particle size of ≤75 μm.

[0040] The zinc selenite of the invention has a selenium content of 40.8%, a zinc content of 34%, a repose angle of 35 degrees, an average particle size of 80 μm, and no color change after being placed in a heat-sealed package for one month.

[0041] Example 2

[0042] A method for recycling zinc selenite waste comprises the following steps:

[0043] (1) 250 g of selenium dioxide, 35 g of zinc selenite waste, and 3.3 L of water were mixed and filtered to obtain a mixed solution;

[0044] (2) The mixed solution was heated to 80° C. and stirred at 400 rpm, 40 g of zinc selenite fine material was added to the mixed solution at a rate of 4 g / min, and zinc oxide was added at a rate of 4 g / min to adjust the pH to 4, reacted at 80° C. for 2 h, filtered, washed with water to a pH of 7, and dried in an oven at 100° C. for 24 h to obtain zinc selenite.

[0045] The zinc selenite waste material is reddish zinc selenite. The zinc selenite fine material refers to zinc selenite with an average particle size of ≤75 μm.

[0046] The zinc selenite of the invention has a selenium content of 40.7%, a zinc content of 34.1%, a repose angle of 33.8°, an average particle size of 130 μm, and no color change after being placed in a heat-sealed package for one month.

[0047] Example 3

[0048] A method for recycling zinc selenite waste comprises the following steps:

[0049] (1) 250 g of selenium dioxide, 30 g of zinc selenite waste, and 3.3 L of water were mixed and filtered to obtain a mixed solution;

[0050] (2) The mixed solution was heated to 70° C. and stirred at 400 rpm. 30 g of zinc selenite fine material was added to the mixed solution at a rate of 2 g / min. Zinc oxide was then added at a rate of 2 g / min to adjust the pH to 3. The mixture was reacted at 70° C. for 1.5 h, filtered, washed with water to a pH of 6, and dried in an oven at 105° C. for 20 h to obtain zinc selenite.

[0051] The zinc selenite waste material is reddish zinc selenite. The zinc selenite fine material refers to zinc selenite with an average particle size of ≤75 μm.

[0052] The zinc selenite of the invention has a selenium content of 41%, a zinc content of 33.9%, an angle of repose of 32.8°, an average particle size of 145 μm, and no color change after being placed in a heat-sealed package for one month.

[0053] Comparative Example 1

[0054] The difference between Comparative Example 1 and Example 3 is that the reaction temperature of Comparative Example 1 is 50°C.

[0055] A method for recycling zinc selenite waste comprises the following steps:

[0056] (1) 250 g of selenium dioxide, 30 g of zinc selenite waste, and 3.3 L of water were mixed and filtered to obtain a mixed solution;

[0057] (2) The mixed solution was heated to 50° C. and stirred at 400 rpm. 30 g of zinc selenite fine material was added to the mixed solution at a rate of 2 g / min. Zinc oxide was then added at a rate of 2 g / min to adjust the pH to 3. The mixture was reacted at 50° C. for 1.5 h, filtered, washed with water to a pH of 6, and dried in an oven at 105° C. for 20 h to obtain zinc selenite.

[0058] The zinc selenite waste material is reddish zinc selenite. The zinc selenite fine material refers to zinc selenite with an average particle size of ≤75 μm.

[0059] The zinc selenite of the invention has a selenium content of 40.7%, a zinc content of 33.8%, a repose angle of 43°, an average particle size of 70 μm, and no color change after being placed in a heat-sealed package for one month.

[0060] Comparative Example 2

[0061] The difference between Comparative Example 2 and Example 3 is that the rate of adding zinc selenite fine material and zinc oxide in Comparative Example 2 is 5 g / min.

[0062] A method for recycling zinc selenite waste comprises the following steps:

[0063] (1) 250 g of selenium dioxide, 30 g of zinc selenite waste, and 3.3 L of water were mixed and filtered to obtain a mixed solution;

[0064] (2) The mixed solution was heated to 70° C. and stirred at 400 rpm. 30 g of zinc selenite fine material was added to the mixed solution at a rate of 5 g / min, and zinc oxide was added at a rate of 5 g / min to adjust the pH to 3. The mixture was reacted at 70° C. for 1.5 h, filtered, washed with water to a pH of 6, and dried in an oven at 105° C. for 20 h to obtain zinc selenite.

[0065] The zinc selenite waste material is reddish zinc selenite. The zinc selenite fine material refers to zinc selenite with an average particle size of ≤75 μm.

[0066] The zinc selenite of the invention has a selenium content of 40.9%, a zinc content of 34.1%, a repose angle of 44 degrees, an average particle size of 60 μm, and no color change after being placed in a heat-sealed package for one month.

[0067] Comparative Example 3

[0068] The difference between Comparative Example 3 and Example 3 is that the rate of adding zinc selenite fine material and zinc oxide in Comparative Example 2 is 0.5 g / min.

[0069] A method for recycling zinc selenite waste comprises the following steps:

[0070] (1) 250 g of selenium dioxide, 30 g of zinc selenite waste, and 3.3 L of water were mixed and filtered to obtain a mixed solution;

[0071] (2) The mixed solution was heated to 70° C. and stirred at 400 rpm. 30 g of zinc selenite fine material was added to the mixed solution at a rate of 0.5 g / min. Zinc oxide was then added at a rate of 0.5 g / min to adjust the pH to 3. The mixture was reacted at 70° C. for 1.5 h, filtered, washed with water to a pH of 6, and dried in an oven at 105° C. for 20 h to obtain zinc selenite.

[0072] The zinc selenite waste material is reddish zinc selenite. The zinc selenite fine material refers to zinc selenite with an average particle size of ≤75 μm.

[0073] The zinc selenite of the invention has a selenium content of 41.1%, a zinc content of 34.0%, an angle of repose of 32.6°, an average particle size of 160 μm, and no color change after being placed in a heat-sealed package for one month.

[0074] Comparative Example 4

[0075] The difference between Comparative Example 4 and Example 3 is that zinc oxide is added to adjust the pH to 2 in Comparative Example 4.

[0076] A method for recycling zinc selenite waste comprises the following steps:

[0077] (1) 250 g of selenium dioxide, 30 g of zinc selenite waste, and 3.3 L of water were mixed and filtered to obtain a mixed solution;

[0078] (2) The mixed solution was heated to 70° C. and stirred at 400 rpm. 30 g of zinc selenite fine material was added to the mixed solution at a rate of 2 g / min. Zinc oxide was then added at a rate of 2 g / min to adjust the pH to 2. The mixture was reacted at 70° C. for 1.5 h, filtered, washed with water to a pH of 6, and dried in an oven at 105° C. for 20 h to obtain zinc selenite.

[0079] The zinc selenite waste material is reddish zinc selenite. The zinc selenite fine material refers to zinc selenite with an average particle size of ≤75 μm.

[0080] The zinc selenite of the invention has a selenium content of 41.4%, a zinc content of 33.5%, a repose angle of 41 degrees, an average particle size of 85 micrometers, and turns red after being placed in a heat-sealed package for one month.

[0081] Comparative Example 5

[0082] The difference between Comparative Example 5 and Example 3 is that zinc oxide is added to adjust the pH to 5 in Comparative Example 4.

[0083] A method for recycling zinc selenite waste comprises the following steps:

[0084] (1) 250 g of selenium dioxide, 30 g of zinc selenite waste, and 3.3 L of water were mixed and filtered to obtain a mixed solution;

[0085] (2) The mixed solution was heated to 70° C. and stirred at 400 rpm. 30 g of zinc selenite fine material was added to the mixed solution at a rate of 2 g / min. Zinc oxide was then added at a rate of 2 g / min to adjust the pH to 5. The mixture was reacted at 70° C. for 1.5 h, filtered, washed with water to a pH of 6, and dried in an oven at 105° C. for 20 h to obtain zinc selenite.

[0086] The zinc selenite waste material is reddish zinc selenite. The zinc selenite fine material refers to zinc selenite with an average particle size of ≤75 μm.

[0087] The zinc selenite of the invention has a selenium content of 40.2%, a zinc content of 34.7%, a repose angle of 40 degrees, an average particle size of 120 micrometers, and turns red after being placed in a heat-sealed package for one month.

[0088] Comparative Example 6

[0089] The difference between Comparative Example 6 and Example 3 is that Comparative Example 6 is washed with water until the pH value is 4.

[0090] A method for recycling zinc selenite waste comprises the following steps:

[0091] (1) 250 g of selenium dioxide, 30 g of zinc selenite waste, and 3.3 L of water were mixed and filtered to obtain a mixed solution;

[0092] (2) The mixed solution was heated to 70° C. and stirred at 400 rpm. 30 g of zinc selenite fine material was added to the mixed solution at a rate of 2 g / min. Zinc oxide was then added at a rate of 2 g / min to adjust the pH to 3. The mixture was reacted at 70° C. for 1.5 h, filtered, washed with water to a pH of 4, and dried in an oven at 105° C. for 20 h to obtain zinc selenite.

[0093] The zinc selenite waste material is reddish zinc selenite. The zinc selenite fine material refers to zinc selenite with an average particle size of ≤75 μm.

[0094] The zinc selenite of the invention has a selenium content of 40.9%, a zinc content of 34.1%, a repose angle of 40 degrees, an average particle size of 125 micrometers, and turns red after being placed in a heat-sealed package for one month.

[0095] Comparative Example 7

[0096] The difference between Comparative Example 7 and Example 3 is that the comparative example 7 is washed with water until the pH value is 8.

[0097] A method for recycling zinc selenite waste comprises the following steps:

[0098] (1) 250 g of selenium dioxide, 30 g of zinc selenite waste, and 3.3 L of water were mixed and filtered to obtain a mixed solution;

[0099] (2) The mixed solution was heated to 70° C. and stirred at 400 rpm. 30 g of zinc selenite fine material was added to the mixed solution at a rate of 2 g / min. Zinc oxide was then added at a rate of 2 g / min to adjust the pH to 3. The mixture was reacted at 70° C. for 1.5 h, filtered, washed with water to a pH of 8, and dried in an oven at 105° C. for 20 h to obtain zinc selenite.

[0100] The zinc selenite waste material is reddish zinc selenite. The zinc selenite fine material refers to zinc selenite with an average particle size of ≤75 μm.

[0101] The zinc selenite of the present invention has a selenium content of 40.2%, a zinc content of 33.4%, a repose angle of 41°, an average particle size of 127 μm, and no color change after being placed in a heat-sealed package for one month.

[0102] Finally, it should be noted that the above embodiments are only used to illustrate the technical solution of the present invention rather than to limit the scope of protection of the present invention. Although the present invention has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that the technical solution of the present invention can be modified or replaced by equivalents without departing from the essence and scope of the technical solution of the present invention.

Claims

1. A method for recycling zinc selenite waste, characterized in that: The following steps are involved: (1) mixing selenium dioxide, zinc selenite waste and water uniformly, filtering and obtaining a mixed solution; (2) heating and stirring the mixed solution, adding zinc selenite fine material to the mixed solution, and then adding zinc oxide to adjust the pH to 2.5-4, reacting, filtering, washing with water to a pH of 5-7, and drying to obtain zinc selenite.

2. The method for recycling zinc selenite waste according to claim 1, characterized in that: The solid-liquid ratio of the selenium dioxide, zinc selenite waste and water is (200-300) g: (10-35) g: 3.3L.

3. The method for recycling zinc selenite waste according to claim 1, characterized in that: The solid-liquid ratio of the zinc selenite fine material to water is (25-40):3.3L.

4. The method for recycling zinc selenite waste according to claim 1, characterized in that: The addition rate of the zinc selenite fine material is (1-4)×(x / 3.3) g / min, where x is the volume of water in step (1).

5. The method for recycling zinc selenite waste according to claim 1, characterized in that: The zinc oxide addition rate is 1-4×(x / 3.3) g / min, where x is the volume of water in step (1).

6. The method for recycling zinc selenite waste according to claim 1, characterized in that: The reaction temperature is 60-80° C., and the reaction time is 1-2 hours.

7. The method for recycling zinc selenite waste according to claim 1, characterized in that: The stirring rate is 300-400 rpm.

8. The method for recycling zinc selenite waste according to claim 1, characterized in that: The heating temperature is 60-80°C.

9. The method for recycling zinc selenite waste according to claim 1, characterized in that: The drying temperature is 100-110° C., and the drying time is 16-24 hours.

10. The method for recycling zinc selenite waste according to claim 1, characterized in that: The zinc selenite has a selenium content of 40.7% to 41.2%, a zinc content of 33.7% to 34.2%, an angle of repose less than 42°, and an average particle size of 75 μm to 150 μm.