An environment-friendly dust suppressant for mineral powder and its preparation method

Abstract

The present invention provides an environment-friendly mineral powder dust suppressant and a preparation method thereof, comprising: performing composite modification on guar gum and / or linseed gum to introduce sulfoethyl groups and carboxymethyl groups; mixing the composite-modified guar gum and / or linseed gum with pregelatinized starch or not mixing with pregelatinized starch to obtain the environment-friendly mineral powder dust suppressant. In the present invention, guar gum and / or linseed gum react in ethanol, with good reaction efficiency and uniformity. Sulfoethyl groups and carboxymethyl groups are introduced onto the molecules of guar gum or linseed gum, increasing its viscosity and improving the water solubility rate, the strength and toughness after film formation. Using the composite-modified guar gum and linseed gum as film-forming agents and binders solves the problems of the complex preparation method of the currently used mineral powder dust suppressant, the poor strength and toughness of the crust layer during use, difficult natural degradation, environmental pollution, etc., solves the pollution problems generated during the traditional mineral powder dust suppression process, and improves and enhances the ecological environment.

Description

Technical Field

[0001] The present invention belongs to the technical field of dust suppression for mineral powder, and particularly relates to a novel environmental protection mineral powder dust suppressant and a preparation method thereof. Background Art

[0002] The iron and steel industry is a basic industry in China's industrial system and plays a crucial role in the development of the national economy. In 2021, China's iron ore mining volume was approximately 360 million tons, ranking third globally, while China's iron ore import volume was even higher, reaching 1.124 billion tons in 2021, firmly ranking first among all countries in the world. As the most basic raw material for steel smelting, China's iron ore is mainly distributed in the northeast and north China regions, while steel enterprises are more concentrated in the north China, east China, and south China regions. The uneven distribution of domestic production and demand of iron ore and the large import volume will inevitably lead to a large amount of iron ore powder being transported over long distances.

[0003] Due to the advantages of fast speed, large transportation volume, low cost, and little influence by weather, railway transportation has become the main way for mineral powder transportation. During the railway transportation of mineral powder, due to the bumps caused by roadbed, turnouts, and rail facilities or the "piston wind" generated when passing through tunnels, a momentary powerful disturbance airflow is formed, causing mineral powder and particles to fly off, resulting in problems such as a large amount of dust pollution and transportation safety, seriously polluting the environment along the line, posing a serious threat to the air environment of surrounding cities, and bringing huge economic losses at the same time. In view of the dust pollution and resource waste problems caused by iron ore powder during storage and transportation, the currently more practical and novel method is the chemical dust suppressant method. By spraying the mineral powder dust suppressant, a crust layer with a thickness greater than 10 mm is formed on the surface of the mineral powder, so that the crust layer will not peel off during the train's driving, which well inhibits the flying off of mineral powder and particles and achieves a good dust suppression effect. This method is simple in construction, good in effect, time-saving and labor-saving, low in cost, and easy to implement, and is a good method to solve the problem of mineral powder and particles flying off.

[0004] The chemical mineral powder dust suppressant is sprayed on the surface of the mineral powder and quickly penetrates into the mineral powder to form a crust layer with a certain thickness (10 - 20 mm) to prevent the flying off of mineral powder and particles. Although it achieves a good dust suppression effect, it has the disadvantages of complex preparation process, poor strength and toughness of the crust layer, difficult degradation, and environmental pollution, which to a certain extent limits the application of the chemical mineral powder dust suppressant. Therefore, it is of great significance to develop a novel environmental protection mineral powder dust suppressant that can solve the above problems.

[0005] Compared with the chemical mineral powder dust suppressant, the novel environmental protection mineral powder dust suppressant has greater practicality and development and promotion potential because it uses natural and degradable raw materials, has good performance, no pollution, simple preparation process, low consumption of resources and energy, and has ecological environment coordination and compatibility. Summary of the Invention

[0006] To solve the above technical problems, the present invention provides an environment-friendly dust suppressant for mineral powder and a preparation method thereof. By compound modification of sophorae bean gum and linseed gum, the cold water instant solubility and complete solubility properties are improved.

[0007] To achieve the above object, the present invention provides a preparation method of an environment-friendly dust suppressant for mineral powder, including: performing compound modification on sophorae bean gum and / or linseed gum to introduce sulfethyl groups and carboxymethyl groups onto the molecules of sophorae bean gum and / or linseed gum respectively; mixing the compound-modified sophorae bean gum and / or linseed gum with pregelatinized starch or not mixing with pregelatinized starch to obtain the environment-friendly dust suppressant for mineral powder.

[0008] In an embodiment of the present invention, the step of performing compound modification on sophorae bean gum and / or linseed gum includes:

[0009] S1: Preparation of slurry: Add sophorae bean gum and / or linseed gum into an alcohol solvent, and stir to prepare a slurry;

[0010] S2: Sulfethylation reaction: Add an alkali to the slurry prepared in the step S1, adjust the pH of the slurry to 11 - 13, raise the temperature to a certain temperature for reaction; then add a sulfethylation reagent, and continue to raise the temperature for reaction;

[0011] S3: Carboxymethylation reaction: After the sulfethylation reaction in the step S2 ends, continue to add a carboxymethylation reagent, heat to a certain temperature for reaction; after the reaction ends, naturally cool, and adjust to a pH of 7 - 8 with an acid to prepare a mixed solution of sulfethylated and carboxymethylated products;

[0012] S4: Post-treatment: Concentrate, centrifuge, wash with ethanol, dry, and then pulverize and screen the mixed solution of sulfethylated and carboxymethylated products to obtain a carboxymethyl-sulfethyl compound-modified product.

[0013] In an embodiment of the present invention, the alcohol solvent in the step S1 is one or more of methanol, ethanol, propanol, and isopropanol. For example, the alcohol solvent is ethanol with a volume concentration of 95%.

[0014] Preferably, the sulfethylation reagent is sodium 2-chloroethylsulfonate, 2-chloroethylsulfonic acid, sodium 2-bromoethylsulfonate, 2-bromoethylsulfonic acid.

[0015] Preferably, the carboxymethylation reagent is sodium chloroacetate, chloroacetic acid, bromoacetic acid, sodium bromoacetate, iodoacetic acid, sodium iodoacetate.

[0016] Preferably, the concentration of the sophorae bean gum and / or linseed gum slurry is 0.2 - 0.5 g / mL.

[0017] For example, 0.2 g / mL, 0.25 g / mL, 0.3 g / mL, 0.35 g / mL, 0.4 g / mL, 0.45 g / mL, 0.46 g / mL, 0.5 g / mL, or any value within the above numerical ranges.

[0018] In one embodiment of the present invention, the mass ratio of the Gleditsia sinensis gum and / or flaxseed gum, 2-chloroethylsulfonate, and sodium chloroacetate is 10:(1 - 2):(1 - 3); preferably 10:1.5:2.

[0019] For example, the mass of the Gleditsia sinensis gum and / or flaxseed gum is 100 parts, the mass of the 2-chloroethylsulfonate is 10 parts, 15 parts, 20 parts, and the mass of the sodium chloroacetate is 10 parts, 15 parts, 20 parts, 25 parts, 30 parts.

[0020] In one embodiment of the present invention, the Gleditsia sinensis gum and / or flaxseed gum is guar gum with a molecular weight of 100,000 - 800,000.

[0021] Preferably, the base in step S2 is sodium hydroxide, potassium hydroxide, lithium hydroxide, or sodium methoxide; the acid in step S3 is hydrochloric acid and / or sulfuric acid.

[0022] In one embodiment of the present invention, the order of the sulfoethylation reaction in step S2 and the carboxymethylation reaction in step S3 can be interchanged.

[0023] In one embodiment of the present invention, in step S2, the temperature is heated to 30 - 60°C, and the reaction time is 30 - 100 min; then it is further heated to 50 - 90°C and reacted for 80 - 100 minutes.

[0024] Preferably, in step S3, it is heated to a temperature of 30 - 90°C, and the reaction time is 60 - 120 min.

[0025] In one embodiment of the present invention, in step S4, the drying method is flash drying, drum drying, or spray drying.

[0026] For example, the drying method is drum drying, and the drum rotation speed is 20 - 50 rpm.

[0027] Preferably, the drying temperature is 80 - 120°C, and the drying time is 5 - 30 min.

[0028] Preferably, the sieving is 60 - 200 mesh.

[0029] In one embodiment of the present invention, in the environmentally friendly mineral powder dust suppressant, the content of the composite modified Gleditsia sinensis gum and / or flaxseed gum is not less than 1%.

[0030] Preferably, the mass ratio of the compound-modified Gleditsia sinensis gum and / or linseed gum to the pregelatinized starch is (1 - 4):(16 - 19).

[0031] The present invention also provides an environment-friendly mineral powder dust suppressant, which is obtained by using the preparation method of the above-mentioned environment-friendly mineral powder dust suppressant.

[0032] In one embodiment of the present invention, the present invention also provides the application of the above-mentioned compound-modified Gleditsia sinensis gum or linseed gum in the preparation of a novel environment-friendly mineral powder dust suppressant.

[0033] Advantages of the present invention

[0034] 1) Although Gleditsia sinensis gum and linseed gum have good thickening, film-forming and bonding properties, due to their disadvantages such as slow dissolution rate in water and complete dissolution only when heated above 80°C, their applications are greatly limited. In the present invention, Gleditsia sinensis gum or linseed gum reacts in ethanol, with good reaction efficiency and uniformity. Sulfonethyl groups and carboxymethyl groups are introduced onto the molecules of Gleditsia sinensis gum or linseed gum, increasing their viscosity, improving the water dissolution rate, and the strength and toughness after film formation. By using the compound-modified Gleditsia sinensis gum and linseed gum as film-forming agents and binders, a novel, environment-friendly and biodegradable mineral powder dust suppressant is developed, solving the problems such as the relatively complex preparation method of the currently used mineral powder dust suppressant, poor strength and toughness of the crust layer during use, difficulty in natural degradation, and environmental pollution. The successful development of the novel environment-friendly mineral powder dust suppressant of the present invention will overcome the common technical problems existing in the use of mineral powder dust suppressants, solve the pollution problems generated during the traditional mineral powder dust suppression process, and improve and enhance the ecological environment.

[0035] 2) By adjusting the pH value, the present invention can adjust the degree of sulfonethylation and carboxymethylation reactions, and further control the ratio of sulfonethyl groups to carboxymethyl groups in the molecular chain of Gleditsia sinensis gum or linseed gum, preparing an environment-friendly mineral powder dust suppressant with rapid cold water solubility, low wind erosion rate, high thickness of the solidified layer, and adjustable viscosity.

[0036] 3) The product of the present invention has a high viscosity, can be added as needed, has a simple process operation, is easy for industrial production, and can be naturally degraded without pollution after being applied to the mineral powder dust suppressant. It is an environment-friendly mineral powder dust suppressant. Specific embodiments

[0037] The following will further elaborate on the preparation method and application of the present invention with specific examples. It should be understood that the following examples are only for illustrative and explanatory purposes of the present invention, and should not be construed as limiting the protection scope of the present invention. All technologies implemented based on the above content of the present invention are covered within the scope of protection intended by the present invention.

[0038] Unless otherwise specified, the raw materials and reagents used in the following examples are all commercially available products or can be prepared by known methods.

[0039] Gleditsia sinensis gum is a white or milky white powder, which is a polysaccharide polymer mainly composed of a D-pyranmannose main chain connected by β-(1,4)-glycosidic bonds and a D-pyran galactose side chain connected by α-(1,6)-glycosidic bonds. The ratio of galactose to mannose is 1:3 to 1:4. Linseed gum, also known as frankel gum and sesame gum, is a powdery product made from the seeds or seed coats of flax through processing techniques such as extraction, concentration, refining, and drying. Gleditsia sinensis gum and linseed gum are rich in sources, are easy to biodegradable, are easy to modify, and are pollution-free to the environment.

[0040] Example 1

[0041] 1) Preparation of pulp emulsion: First, put 200 parts by weight of 95% ethanol into a reaction kettle, start the stirrer, and add 100 parts by weight of linseed gum powder to prepare a linseed gum pulp emulsion; the concentration of the linseed gum pulp emulsion is 0.45 g / mL.

[0042] 2) Sulfonethylation reaction: Add sodium hydroxide powder to the linseed gum pulp emulsion to adjust the pH to 13.0, react at 35 °C for 30 min; raise the temperature to 55 °C, add 10 parts by weight of 2-chloroethylsulfonate, and react for 100 min.

[0043] 3) Carboxymethylation reaction: Add 10 parts by weight of sodium chloroacetate, raise the temperature to 60 °C, and react for 80 min; obtain the reaction solution of sulfonethylation and carboxymethylation; after naturally cooling to room temperature, add hydrochloric acid solution to adjust the pH to 7-8.

[0044] 4) Post-treatment: Concentrate and centrifuge the reaction solution, wash it with 20 parts by weight of 95% ethanol, drum dry it under the condition of a rotation speed of 20-50 rpm, and then pulverize and sieve it to obtain sulfonethyl carboxymethyl linseed gum (SECMLG-1).

[0045] Example 2

[0046] 1) Preparation of pulp emulsion: First, put 200 parts by weight of 95% ethanol into a reaction kettle, start the stirrer, and add 100 parts by weight of linseed gum powder to prepare a linseed gum pulp emulsion; the concentration of the linseed gum pulp emulsion is 0.45 g / mL.

[0047] 2) Sulfonethylation reaction: Add sodium hydroxide powder to the linseed gum pulp emulsion to adjust the pH to 13.0, react at 35 °C for 30 min; raise the temperature to 55 °C, add 10 parts by weight of 2-chloroethylsulfonate, and react for 100 min.

[0048] 3) Carboxymethylation reaction: Add 15 parts by weight of sodium chloroacetate, heat up to 60 °C, and react for 80 min; obtain the reaction solution of sulfoethylation and carboxymethylation; after naturally cooling to room temperature, add hydrochloric acid solution to adjust the pH to 7 - 8.

[0049] 4) Post-treatment: Concentrate and centrifuge the reaction solution, wash it with 20 parts by weight of 95% ethanol, perform drum drying under the condition of a rotation speed of 20 - 50 rpm, then pulverize and sieve to obtain sulfoethyl carboxymethyl flaxseed gum (SECMLG-2).

[0050] Example 3

[0051] 1) Preparation of pulp emulsion: First, place 200 parts by weight of 95% ethanol into a reaction kettle, start the stirrer, and add 100 parts by weight of flaxseed gum powder to prepare a flaxseed gum pulp emulsion; the concentration of the flaxseed gum pulp emulsion is 0.45 g / mL.

[0052] 2) Sulfoethylation reaction: Add sodium hydroxide powder to the flaxseed gum pulp emulsion to adjust the pH to 13.0, react at 35 °C for 50 min; heat up to 60 °C, add 10 parts by weight of 2-chloroethyl sulfonate, and react for 120 min.

[0053] 3) Carboxymethylation reaction: Add 20 parts by weight of sodium chloroacetate, heat up to 80 °C, and react for 60 min. Obtain the reaction solution of sulfoethylation and carboxymethylation; after naturally cooling to room temperature, add hydrochloric acid solution to adjust the pH to 7 - 8;

[0054] 4) Post-treatment: Concentrate and centrifuge the reaction solution, wash it with 20 parts by weight of 95% ethanol, perform drum drying under the condition of a rotation speed of 20 - 50 rpm, then pulverize and sieve to obtain sulfoethyl carboxymethyl flaxseed gum (SECMLG-3).

[0055] Example 4

[0056] 1) Preparation of pulp emulsion: First, place 200 parts by weight of 95% ethanol into a reaction kettle, start the stirrer, and add 100 parts by weight of flaxseed gum powder to prepare a flaxseed gum pulp emulsion; the concentration of the flaxseed gum pulp emulsion is 0.45 g / mL.

[0057] 2) Sulfoethylation reaction: Add sodium hydroxide powder to the flaxseed gum pulp emulsion to adjust the pH to 13.0, react at 50 °C for 30 min; heat up to 70 °C, add 15 parts by weight of 2-chloroethyl sulfonate, and react for 100 min.

[0058] 3) Carboxymethylation reaction: Add 20 parts by weight of sodium chloroacetate, heat up to 80 °C, and react for 100 min; obtain the reaction solution of sulfoethylation and carboxymethylation; after naturally cooling to room temperature, add hydrochloric acid solution to adjust the pH to 7 - 8.

[0059] 4) Post-treatment: Concentrate and centrifuge the reaction solution, wash it with 20 parts by weight of 95% ethanol, perform drum drying under the condition of a rotation speed of 20 - 50 rpm, and then pulverize and screen it to obtain sulfonated ethyl carboxymethyl flaxseed gum (SECMLG-4).

[0060] Example 5

[0061] 1) Preparation of pulp emulsion: First, place 200 parts by weight of 95% ethanol into a reaction kettle, start the stirrer, and add 100 parts by weight of Gleditsia sinensis gum powder to prepare a Gleditsia sinensis gum pulp emulsion; the concentration of the Gleditsia sinensis gum pulp emulsion is 0.46 g / mL.

[0062] 2) Sulfonated ethyl reaction: Add sodium hydroxide powder to the Gleditsia sinensis gum pulp emulsion to adjust the pH to 13.0, react at 35 °C for 20 min; continue to heat up to 55 °C, add 10 parts by weight of 2-chloroethyl sulfonate, and react for 100 min.

[0063] 3) Carboxymethylation reaction: Add 10 parts by weight of sodium chloroacetate, heat up to 60 °C, and react for 80 min. Obtain the reaction solution of sulfonated ethyl and carboxymethylation; after naturally cooling to room temperature, add hydrochloric acid solution to adjust the pH to 7 - 8;

[0064] 4) Post-treatment: Concentrate and centrifuge the reaction solution, wash it with 20 parts by weight of 95% ethanol, perform drum drying under the condition of a rotation speed of 20 - 50 rpm, and then pulverize and screen it to obtain sulfonated ethyl carboxymethyl Gleditsia sinensis gum (SECMGSLG-1).

[0065] Example 6

[0066] 1) Preparation of pulp emulsion: First, place 200 parts by weight of 95% ethanol into a reaction kettle, start the stirrer, and add 100 parts by weight of Gleditsia sinensis gum powder to prepare a Gleditsia sinensis gum pulp emulsion; the concentration of the Gleditsia sinensis gum pulp emulsion is 0.46 g / mL.

[0067] 2) Sulfonated ethyl reaction: Add sodium hydroxide powder to the Gleditsia sinensis gum pulp emulsion to adjust the pH to 13.0, react at 35 °C for 60 min; heat up to 55 °C, add 10 parts by weight of 2-chloroethyl sulfonate, and react for 100 min.

[0068] 3) Carboxymethylation reaction: Add 15 parts by weight of sodium chloroacetate, heat up to 60 °C, and react for 80 min; obtain the reaction solution of sulfonated ethyl and carboxymethylation; after naturally cooling to room temperature, add hydrochloric acid solution to adjust the pH to 7 - 8.

[0069] 4) Post-treatment: Concentrate and centrifuge the reaction solution, wash it with 20 parts by weight of 95% ethanol, perform drum drying under the condition of a rotation speed of 20 - 50 rpm, and then pulverize and screen it to obtain sulfonated ethyl carboxymethyl Gleditsia sinensis gum (SECMGSLG-2).

[0070] Example 7

[0071] 1) Preparation of pulp milk: First, put 200 parts by weight of 95% ethanol into a reaction kettle, start the stirrer, and add 100 parts by weight of Gleditsia sinensis gum powder to prepare Gleditsia sinensis gum pulp milk; the concentration of Gleditsia sinensis gum pulp milk is 0.46 g / mL.

[0072] 2) Sulfonatoethylation reaction: Add sodium hydroxide powder to the Gleditsia sinensis gum pulp milk to adjust the pH to 13.0, react at 35 °C for 60 min; raise the temperature to 65 °C, add 10 parts by weight of 2-chloroethylsulfonic acid sodium, and react for 100 min.

[0073] 3) Carboxymethylation reaction: Add 20 parts by weight of sodium chloroacetate, react at 60 °C for 80 min; obtain the reaction solution of sulfonatoethylation and carboxymethylation; after naturally cooling to room temperature, add hydrochloric acid solution to adjust the pH to 7 - 8.

[0074] 4) Post-treatment: Concentrate and centrifuge the reaction solution, wash it with 20 parts by weight of 95% ethanol, drum dry it under the condition of a rotation speed of 20 - 50 rpm, and then pulverize and sieve it to obtain sulfonatoethyl carboxymethyl Gleditsia sinensis gum (SECMGSLG-3).

[0075] Example 8

[0076] 1) Preparation of pulp milk: First, put 200 parts by weight of 95% ethanol into a reaction kettle, start the stirrer, and add 100 parts by weight of Gleditsia sinensis gum powder to prepare Gleditsia sinensis gum pulp milk; the concentration of Gleditsia sinensis gum pulp milk is 0.46 g / mL.

[0077] 2) Sulfonatoethylation reaction: Add sodium hydroxide powder to the Gleditsia sinensis gum pulp milk to adjust the pH to 13.0, react at 35 °C for 50 min; raise the temperature to 60 °C, add 15 parts by weight of 2-chloroethylsulfonic acid sodium, and react for 100 min.

[0078] 3) Carboxymethylation reaction: Add 20 parts by weight of sodium chloroacetate, react at 60 °C for 80 min; obtain the reaction solution of sulfonatoethylation and carboxymethylation; after naturally cooling to room temperature, add hydrochloric acid solution to adjust the pH to 7 - 8.

[0079] 4) Post-treatment: Concentrate and centrifuge the reaction solution, wash it with 20 parts by weight of 95% ethanol, drum dry it under the condition of a rotation speed of 20 - 50 rpm, and then pulverize and sieve it to obtain sulfonatoethyl carboxymethyl Gleditsia sinensis gum (SECMGSLG-4).

[0080] Example 9

[0081] 1) Preparation of pulp milk: First, put 200 parts by weight of 95% ethanol into a reaction kettle, start the stirrer, and add 100 parts by weight of Gleditsia sinensis gum powder to prepare Gleditsia sinensis gum pulp milk; the concentration of Gleditsia sinensis gum pulp milk is 0.46 g / mL.

[0082] 2) Sulfethylation reaction: Sodium hydroxide powder was added to the sophorae gum latex to adjust the pH to 13.0, and the reaction was carried out at 35 °C for 40 min; the temperature was raised to 65 °C, and 15 parts by weight of sodium 2-chloroethylsulfonate was added, and the reaction was carried out for 120 min.

[0083] 3) Carboxymethylation reaction: 30 parts by weight of sodium chloroacetate was added, and the reaction was carried out at 60 °C for 100 min; the reaction solution of sulfethylation and carboxymethylation was obtained; after naturally cooling to room temperature, a hydrochloric acid solution was added to adjust the pH to 7 - 8.

[0084] 4) Post-treatment: The reaction solution was concentrated and centrifuged, washed with 20 parts by weight of 95% ethanol, drum-dried under the condition of a rotation speed of 20 - 50 rpm, and then pulverized and sieved to obtain sulfethyl carboxymethyl sophorae gum (SECMGSLG - 5).

[0085] Comparative Example 1

[0086] 1) Preparation of latex blend: First, 200 parts by weight of 95% ethanol was placed into a reaction kettle, the stirrer was started, and 100 parts by weight of sophorae gum powder was added to prepare sophorae gum latex; the concentration of the sophorae gum latex was 0.46 g / mL.

[0087] 2) Sulfethylation reaction: Sodium hydroxide powder was added to the sophorae gum latex to adjust the pH to 13.0, the reaction was carried out at 35 °C for 30 min, the temperature was raised to 55 °C, 20 parts by weight of sodium 2-chloroethylsulfonate was added, and the reaction was carried out for 100 min; after naturally cooling to room temperature, a hydrochloric acid solution was added to adjust the pH to 7 - 8.

[0088] 3) Post-treatment: The reaction solution was concentrated and centrifuged, washed with 20 parts by weight of 95% ethanol, drum-dried under the condition of a rotation speed of 20 - 50 rpm, and then pulverized and sieved to obtain sulfethyl sophorae gum (SECMGSLG - 6).

[0089] Comparative Example 2

[0090] 1) Preparation of latex blend: First, 200 parts by weight of 95% ethanol was placed into a reaction kettle, the stirrer was started, and 100 parts by weight of sophorae gum powder was added to prepare sophorae gum latex; the concentration of the sophorae gum latex was 0.46 g / mL.

[0091] 2) Carboxymethylation reaction: Sodium hydroxide powder was added to the sophorae gum latex to adjust the pH to 13.0, the reaction was carried out at 35 °C for 30 min; 20 parts by weight of sodium chloroacetate was added, the temperature was raised to 60 °C, and the reaction was carried out for 80 min; after naturally cooling to room temperature, a hydrochloric acid solution was added to adjust the pH to 7 - 8.

[0092] 3) Post-treatment: Concentrate and centrifuge the reaction solution, wash it with 20 parts by weight of 95% ethanol, drum dry it under the condition of a rotation speed of 20 - 50 rpm, and then pulverize and screen it to obtain carboxymethyl sophora japonica gum (SECMGSLG - 7).

[0093] Comparative Example 3

[0094] 1) Preparation of pulp and latex: First, place 200 parts by weight of 95% ethanol into a reaction kettle, start the stirrer, and add 100 parts by weight of flaxseed gum powder to prepare flaxseed gum pulp and latex; the concentration of the flaxseed gum pulp and latex is 0.45 g / mL.

[0095] 2) Carboxymethylation reaction: Add sodium hydroxide powder to the flaxseed gum pulp and latex to adjust the pH to 13.0, react at 35°C for 30 min; add 20 parts by weight of sodium chloroacetate, raise the temperature to 60°C, and react for 80 min; after naturally cooling to room temperature, add hydrochloric acid solution to adjust the pH to 7 - 8.

[0096] 3) Post-treatment: Concentrate and centrifuge the reaction solution, wash it with 20 parts by weight of 95% ethanol, drum dry it under the condition of a rotation speed of 20 - 50 rpm, and then pulverize and screen it to obtain carboxymethyl flaxseed gum (SECMFG - 5).

[0097] Comparative Example 4

[0098] 1) Preparation of pulp and latex: First, place 200 parts by weight of 95% ethanol into a reaction kettle, start the stirrer, and add 100 parts by weight of flaxseed gum powder to prepare flaxseed gum pulp and latex; the concentration of the flaxseed gum pulp and latex is 0.45 g / mL.

[0099] 2) Carboxymethylation reaction: Add sodium hydroxide powder to the flaxseed gum pulp and latex to adjust the pH to 13.0, react at 35°C for 30 min; add 20 parts by weight of 2 - chloroethyl sulfonate, raise the temperature to 60°C, and react for 100 min; after naturally cooling to room temperature, add hydrochloric acid solution to adjust the pH to 7 - 8.

[0100] 3) Post-treatment: Concentrate and centrifuge the reaction solution, wash it with 20 parts by weight of 95% ethanol, drum dry it under the condition of a rotation speed of 20 - 50 rpm, and then pulverize and screen it to obtain carboxymethyl flaxseed gum (SECMFG - 6).

[0101] Application Example

[0102] Weigh 10 g of the modified sophora japonica gum or flaxseed gum prepared in Examples 1 - 9 and Comparative Examples 1 - 4, and 90 g of pregelatinized starch, mix them evenly to obtain a sample of a new type of environmentally friendly mineral powder dust suppressant.

[0103] Viscosity measurement:

[0104] Weigh 1 g of the new environmentally friendly mineral powder dust suppressant sample, add it to 99 g of water, stir for 30 min, place it in a water bath at 25 °C and keep it warm for 20 min. Use a DV2TLVTJ0 viscometer, 0 rotor, 1 rotor, and a rotation speed of 60 r / min to measure the viscosity of the sample solution. The viscosity measurement standard: It is measured in accordance with the first part of the Technical Conditions for Dust Suppression Technology in Railway Coal Transportation, TB / T 3210.1 - 2020, of the Railway Industry Standard of the People's Republic of China.

[0105] Determination of pH value:

[0106] (1) Soak the glass electrode of the pH meter according to the instructions of the pH meter. Select two standard buffer solutions with pH values close to that of the same sample to calibrate the pH meter.

[0107] (2) Place the beaker containing the sample solution in a constant temperature bath at 25 ± 1 °C. After the temperature reaches a stable equilibrium, rinse the glass electrode with distilled water and dry it, then wash the electrode with the sample solution, and then insert it into the test sample for measurement.

[0108] (3) In three consecutive sample measurements, if the difference in pH values of the three samples is greater than 0.2, three new samples should be taken and measured again until the difference in pH values is not greater than 0.2.

[0109] (4) Take the arithmetic mean of the pH values of the three samples as the experimental result, and retain one decimal place for the value.

[0110] Compressive property determination experiment:

[0111] The compressive strength characterizes the bonding degree after the dust suppressant solution is mixed with iron ore. The compressive strength represents the maximum pressure that the crust layer formed by spraying the dust suppressant can withstand. The greater the compressive strength, the greater the bearing pressure and the better the solidification effect.

[0112] Spray the iron ore sample with the dust suppressant solution at a spraying rate of 3 L / m 2 . After mixing evenly, on a mold with a diameter of 5 cm and a thickness of 10 mm, compact and level it, and then make an iron ore powder mold at one time. Dry it under natural conditions. After drying, place a smooth iron sheet with the same diameter in the made model, place an iron block on the iron sheet, continuously increase the mass of the iron block, and at the same time observe the iron ore powder mold sample until the sample is completely damaged, then weigh the weight of the added iron block and calculate the compressive strength. To ensure the accuracy of the data, each sample is subjected to five compressive tests, and finally the average value is obtained.

[0113] Wind erosion rate and solidified layer thickness determination

[0114] Select iron ore powder with a mesh size of 30 to 100, dry it in an oven at (50 ± 2) °C for 300 min to remove moisture, and place it for 1 h under the conditions of an ambient temperature of (20 ± 5) °C and a humidity ≤ 50%. Take an appropriate amount of the dried iron ore powder and place it separately in 3 (300 mm x 210 mm x 30 mm) sturdy and non-deformable trays that have been weighed to a constant weight w at the experimental temperature, making the surface of the iron ore powder layer flush with the trays. Spray the sample solution on two trays at a spraying rate of 3 L / m 2 After spraying, place them for 1 h under the conditions of an ambient temperature of (20 ± 5) °C and a humidity ≤ 50%, then place them in an oven at (50 ± 2) °C and bake for 120 min, and then weigh them separately. The mass of the iron ore powder and the tray is w1. Put the prepared specimens into the wind tunnel and conduct wind erosion for 30 min under the condition that the surface wind speed of the iron ore powder is (30.0 ± 0.2) m / s, and then weigh them separately. The mass of the remaining iron ore powder and the tray is w2. Finally, calculate the wind erosion rate of the sample according to the following formula respectively;

[0115]

[0116] In the formula:

[0117] E - Wind erosion rate of the sample; w - Mass of the tray; w1 - Mass of the iron ore powder and the tray before wind erosion; w2 - Mass of the iron ore powder and the tray after wind erosion.

[0118] The wind erosion rate of sample solution sample 1 is E1, the wind erosion rate of sample solution sample 2 is E2, and the wind erosion rate of sample solution sample 3 is E3. Take their average value.

[0119] Take six places of the cured layer from sample 1, sample 2, and sample 3 respectively, measure their thicknesses with a measuring tool, and obtain the cured layer thickness of sample 1 as H1, the cured layer thickness of sample 2 as H2, and the cured layer thickness of sample 3 as H3. Take their average value, which is the cured layer thickness. The test results are shown in Table 1.

[0120] Table 1

[0121] Dust suppressant sample Viscosity (mPa·s) pH Compressive strength (kPa) Thickness of solidified layer (mm) Wind erosion rate (%) Example 1 26.2 7.2 52.2 16.3 0.12 Example 2 29.5 7.3 51.5 17.2 0.11 Example 3 35.1 7.2 55.6 18.4 0.09 Example 4 36.3 7.3 56.4 19.2 0.06 Example 5 21.6 7.1 45.3 16.8 0.36 Example 6 23.8 7.1 47.7 16.8 0.28 Example 7 26.5 7.3 48.2 17.0 0.23 Example 8 26.8 7.2 48.9 17.4 0.16 Example 9 28.2 7.3 51.8 17.5 0.15 Comparative example 1 19.9 7.0 35.6 12.6 1.36 Comparative example 2 22.1 7.1 42.4 12.9 1.58 Comparative example 3 19.4 7.1 48.5 11.8 1.76 Comparative example 4 18.5 7.2 46.5 12.5 1.42

[0122] The cold water (20 °C) instant solubility and undissolved substances of modified Gleditsia sinensis gum and linseed gum are shown in Table 2.

[0123] Table 2

[0124]

[0125]

[0126] The modified Gleditsia sinensis gum and flaxseed gum prepared by the method of the present invention are used as film-forming agents and binders in the field of mineral powder dust suppressants. The technical indicators of the mineral powder dust suppressants are related to the degree of sulfoethylation and carboxymethylation reactions. The degree of sulfoethylation reaction has the greatest impact on the cold water rapid solubility of Gleditsia sinensis gum and flaxseed gum, and the carboxymethylation reaction has a greater impact on the viscosity of Gleditsia sinensis gum and flaxseed gum. Only the iron ore powder dust suppressants prepared from Gleditsia sinensis gum and flaxseed gum that are simultaneously sulfoethylated and oxidatively modified meet the standard requirements. Therefore, the sulfoethylation reaction and carboxymethylation reaction are extremely important for the performance of the dust suppressants prepared with modified Gleditsia sinensis gum and flaxseed gum as the main raw materials.

[0127] The embodiments of the present invention have been described above. However, the present invention is not limited to the above embodiments. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principle of the present invention shall be included within the protection scope of the present invention.

Claims

1. A preparation method of an environment-friendly dust suppressant for ore powder, characterized in that, Including: Performing composite modification on gleditsia sinensis gum and / or linseed gum to introduce sulfoethyl groups and carboxymethyl groups onto the molecules of gleditsia sinensis gum and / or linseed gum respectively; Mixing the composite-modified gleditsia sinensis gum and / or linseed gum with pregelatinized starch to obtain the environment-friendly mineral powder dust suppressant; The steps of performing composite modification on gleditsia sinensis gum and / or linseed gum include: S1: Pulp preparation: Adding gleditsia sinensis gum and / or linseed gum into an alcohol solvent and stirring to prepare pulp; S2: Sulfoethylation reaction: Adding an alkali to the pulp prepared in step S1, adjusting the pH of the pulp to 11 - 13, heating to a certain temperature for reaction; then adding a sulfoethylation reagent and continuing to heat for reaction; S3: Carboxymethylation reaction: After the sulfoethylation reaction in step S2 ends, continuously adding a carboxymethylation reagent and heating to a certain temperature for reaction; after the reaction ends, naturally cooling and adjusting to pH 7 - 8 with an acid to prepare a mixed solution of sulfoethylated and carboxymethylated products; S4: Post-treatment: Concentrating, centrifuging, washing with ethanol, drying the mixed solution of sulfoethylated and carboxymethylated products, and then pulverizing and sieving to obtain a carboxymethyl sulfoethyl composite-modified product; In the environment-friendly mineral powder dust suppressant, the content of the composite-modified gleditsia sinensis gum and / or linseed gum is not less than 1%; The mass ratio of the composite-modified gleditsia sinensis gum and / or linseed gum to the pregelatinized starch is (1 - 4):(16 - 19).

2. The preparation method according to claim 1, characterized in that, The alcohol solvent in step S1 is one or more of methanol, ethanol, propanol, and isopropanol.

3. The preparation method according to claim 1, wherein The alcohol solvent is ethanol with a volume concentration of 95%.

4. The preparation method according to claim 1, characterized in that, The sulfoethylation reagent is sodium 2-chloroethylsulfonate, 2-chloroethylsulfonic acid, sodium 2-bromoethylsulfonate, 2-bromoethylsulfonic acid.

5. The preparation method according to claim 4, characterized in that, The carboxymethylation reagent is sodium chloroacetate, chloroacetic acid, bromoacetic acid, sodium bromoacetate, iodoacetic acid, sodium iodoacetate.

6. The preparation method according to claim 1, characterized in that, The concentration of the gleditsia sinensis gum and / or linseed gum pulp is 0.2 - 0.5 g / mL.

7. The preparation method according to claim 3, characterized in that, The concentration of the gleditsia sinensis gum and / or linseed gum pulp is 0.2 g / mL, 0.25 g / mL, 0.3 g / mL, 0.35 g / mL, 0.4 g / mL, 0.45 g / mL, 0.46 g / mL, 0.5 g / mL.

8. The preparation method according to claim 5, characterized in that, The mass ratio of the gleditsia sinensis gum and / or linseed gum, sodium 2-chloroethylsulfonate, and sodium chloroacetate is 10:(1 - 2):(1 - 3).

9. The preparation method according to claim 5, characterized in that, The mass ratio of the gleditsia sinensis gum and / or linseed gum, sodium 2-chloroethylsulfonate, and sodium chloroacetate is 10:1.5:

2.

10. The preparation method according to claim 8, characterized in that, The mass of the gleditsia sinensis gum and / or linseed gum is 100 parts, the mass of the sodium 2-chloroethylsulfonate is 10 parts, 15 parts, 20 parts, and the mass of the sodium chloroacetate is 10 parts, 15 parts, 20 parts, 25 parts, 30 parts.

11. The preparation method according to claim 1, wherein, The gleditsia sinensis gum and / or linseed gum is guar gum with a molecular weight of 100,000 - 800,000.

12. The preparation method according to claim 1, wherein The alkali in step S2 is sodium hydroxide, potassium hydroxide, lithium hydroxide, or sodium methoxide; the acid in step S3 is hydrochloric acid and / or sulfuric acid.

13. The preparation method according to claim 1, characterized in that, The order of the sulfoethylation reaction in step S2 and the carboxymethylation reaction in step S3 can be interchanged.

14. The preparation method according to claim 1, characterized in that, In the step S2, the temperature is heated to 30-60 °C, and the reaction time is 30-100 min; then it is further heated to 50-90 °C and reacts for 80-100 minutes.

15. The preparation method according to claim 1, wherein, In the step S3, it is heated to a temperature of 30-90 °C, and the reaction time is 60-120 min.

16. The preparation method according to claim 1, wherein, In the step S4, the drying method is air drying, drum drying or spray drying.

17. The preparation method according to claim 16, wherein, The drying method is drum drying, and the drum rotation speed is 20-50 rpm.

18. The preparation method according to claim 16, wherein The temperature of the drying is 80-120 °C, and the drying time is 5-30 min.

19. The preparation method according to claim 1, characterized in that, The sieving is 60-200 mesh.

20. An environment-friendly dust suppressant for mineral powder, characterized in that, It is obtained by using the preparation method of the environment-friendly mineral powder dust suppressant according to any one of claims 1 to 19.

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