CN114933889A

CN114933889A - Composite dust suppressant for open-air limestone mine road dust emission and preparation method thereof

Info

Publication number: CN114933889A
Application number: CN202210688384.5A
Authority: CN
Inventors: 张小雨; 柯丽华; 张光权; 胡南燕; 凡雅雯; 唐华倩; 肖泽宇; 孟瑶尧; 刘超军
Original assignee: Wuhan University of Science and Engineering WUSE
Current assignee: Wuhan University of Science and Engineering WUSE
Priority date: 2022-06-16
Filing date: 2022-06-16
Publication date: 2022-08-23

Abstract

The invention discloses a composite dust suppressant for opencast limestone mine road dust emission and a preparation method thereof. Belongs to the field of road dust control. The dust suppressant comprises the following components in percentage by mass: 0.02 to 0.1 percent of guar gum, 0.02 to 0.1 percent of xanthan gum, 0.2 to 0.6 percent of acrylamide, 0.2 to 0.6 percent of wetting agent, 5 to 15 percent of hygroscopic agent, 0.01 to 0.025 percent of initiator, 0.01 to 0.025 percent of cross-linking agent and 83.55 to 94.54 percent of deionized water. The product prepared by the invention has good thermal stability, cohesiveness, permeability and compressive strength, is used for treating dust on the surface limestone mine road, and has good application prospect.

Description

Composite dust suppressant for open-pit limestone mine road raise dust and preparation method thereof

Technical Field

The invention belongs to the field of road dust control, and particularly relates to a composite dust suppressant for open-air limestone mine road dust and a preparation method thereof.

Background

The process of mining the open-pit limestone ore provides necessary flux raw materials for steelmaking, and relates to the production process of perforation rock drilling, blasting, collecting and loading, transportation operation and the like in the process of orderly developing limestone production, the produced dust is usually discharged in an unorganized mode, belongs to a continuous dust pollution source, and has great harm to the production environment and the physical health of personnel, wherein the influence range of road transportation flying dust is large, the pollution amount of secondary flying dust is large, the dispersion degree of dust pollution is high, the dust is suspended in wind flow and is not easy to settle, and therefore the process has continuous adverse influence on the operation environment of the open-pit limestone ore stope. Therefore, the treatment of the dust on the open-air limestone mine road is often an important work for the dust treatment.

At present, the method for inhibiting the dust emission of the open-air limestone mine road mainly adopts the means of sprinkling water, dust inhibition by a covering method, chemical dust inhibition and the like. Although the water sprinkling and dust suppression are simple and easy, the defects of the water sprinkling and dust suppression are not ignored, so that a large amount of water resources are wasted, and simultaneously, the water is disturbed by the outside along with the evaporation of water and can be raised again, the dust suppression period is short, and the dust suppression effect is poor; the covering method uses a large amount of manpower and material resources for dust suppression, the problem can not be effectively solved, and the covering and the environment can be polluted again after the tarpaulin is corroded. The chemical dust suppression has obvious dust suppression effect, can control the cost and is widely applied. However, most of the existing dust depressants are researched aiming at the dust characteristics of coal mines, and the opencast limestone mine road dust has different properties from the coal mine dust and strong hydrophilicity, so that the invention of a chemical dust depressor aiming at the dust characteristics of the opencast limestone mine road is urgently needed.

Therefore, it is an urgent technical problem to be solved by those skilled in the art to provide a chemical dust suppressant which combines the characteristics of limestone mine road dust.

Disclosure of Invention

In view of the above, the invention provides a composite dust suppressant for the road raise dust of an open-pit limestone mine and a preparation method thereof. The composite dust suppressant disclosed by the invention has the advantages of bonding, moisture retention, moisture absorption and the like, effectively prolongs the dust suppression period and enhances the dust suppression effect. By the regular spraying operation, the action of the floating dust on the dust suppressant is quickly reduced to form a bonding layer with certain strength, and the floating dust on the surface of the road is kept moist, so that the aim of suppressing the dust on the road is fulfilled.

In order to achieve the purpose, the invention adopts the following technical scheme:

a composite dust suppressant for opencast limestone mine road dust comprises the following components in percentage by mass: 0.02 to 0.1 percent of guar gum, 0.02 to 0.1 percent of xanthan gum, 0.2 to 0.6 percent of acrylamide, 0.2 to 0.6 percent of wetting agent, 5 to 15 percent of hygroscopic agent, 0.01 to 0.025 percent of initiator, 0.01 to 0.025 percent of cross-linking agent and 83.55 to 94.54 percent of deionized water.

Further, the wetting agent is one of sodium dodecyl benzene sulfonate, fatty alcohol-polyoxyethylene ether and dodecyl dimethyl betaine.

Further, the moisture absorbent is sodium silicate.

Further, the initiator is potassium persulfate.

Further, the cross-linking agent is N, N' -methylene bisacrylamide.

A preparation method of a compound dust suppressant for opencast limestone mine road dust emission comprises the following steps:

(1) adding guar gum and xanthan gum into deionized water, and uniformly stirring to obtain a grafting mixed substrate;

(2) then slowly adding an initiator while stirring, stirring at a medium speed, and initiating a reaction to obtain a material A;

(3) adding a proper amount of acrylamide powder into the material A, and introducing nitrogen in the reaction process to obtain a material B;

(4) slowly adding a cross-linking agent into the material B to initiate graft polymerization to obtain a graft polymerization product;

(5) uniformly scattering a proper amount of wetting agent and moisture absorbent into the copolymer solution in sequence to obtain a material C;

(6) and adjusting the pH value of the material C to be neutral to obtain the compound dust suppressant.

Further, the mass concentration of the grafting mixed substrate solution dissolved in the step (1) is 0.1%; stirring for 30min at 25 deg.C.

The beneficial effect of adopting the further scheme is that: under the condition of stirring for 30min at 25 ℃, the grafting mixed substrate can be completely dissolved, and the solution with the mass concentration of 0.1% ensures that the subsequent product has good viscosity.

Further, parameters of medium-speed stirring in the step (2): the stirring speed is 300-.

The beneficial effect of adopting the above-mentioned further scheme lies in: the stirring speed is 300-1500r/min, the reaction temperature is 60 ℃, the probability of collision of the initiator particles and the grafting substrate particles in the solution can be increased, so that the reaction is initiated, the reaction time is 30min, and the grafting substrate can be more fully initiated.

Further, the speed of introducing nitrogen in the step (3) is 4-6 mL/min; the reaction parameters are 60 ℃ for 30 min.

The beneficial effect of adopting the further scheme is that: introducing nitrogen at a rate of 4-6mL/min to change the reaction environment in the reaction container into an oxygen-free environment and prevent the reaction substrate from being heated and oxidized; the reaction was carried out for 30min so that the grafting monomers could be sufficiently bound to the grafting substrate.

Further, the reaction temperature in the step (4) is 60 ℃, and the reaction time is 1 h.

The beneficial effect of adopting the above-mentioned further scheme lies in: the reaction temperature is 60 ℃ after the cross-linking agent is added, good reaction conditions are provided for the cross-linking polymerization reaction, and the cross-linking polymerization reaction is more sufficient after the reaction time is 1 h.

Further, the stirring time in the step (5) is 30 min; the temperature of the whole reaction process is controlled at 25 ℃.

The beneficial effect of adopting the further scheme is that: the reaction temperature is 25 ℃, the stirring time is 30min, so that the wetting agent and the moisture absorbent can be fully dissolved in the copolymer, the surface tension of the solution is reduced, and the wettability and the moisture absorption of the dust suppressant are improved.

Further, oxalic acid is used to adjust the pH in step (6).

The beneficial effect of adopting the further scheme is that: the pH value is adjusted to be neutral, so that the dust suppression effect of the dust suppressant can be improved, and the damage of the dust suppressant to the environment is reduced.

According to the technical scheme, compared with the prior art, the invention has the following beneficial effects: the invention provides a composite dust suppressant for open-air limestone mine road dust. The binder adopted by the dust suppressant prepared by the invention is natural vegetable gum, and the binder has the advantages of high viscosity performance, cross-linked mesh shape, complex structure and easy degradation. Guar gum and xanthan gum are selected for compounding, synergy is achieved, agglomerated dust particles become large groups and are rapidly settled, and after 36-hour leakage and water evaporation, a hard shell is formed on the surface layer for protection. The compressive strength of the bonding layer is high, so that the road dust is not influenced by wind power, and the secondary dust emission is further reduced. On the basis, the initiator and the cross-linking agent are added, the mixed rubber is grafted with the acrylamide monomer, a large number of hydrophilic groups are introduced, and the water retention capacity of the solution is improved, so that the dust suppression effect is enhanced. In addition, the hydrophilic effect of the solution is improved by reducing the surface tension under the action of the wetting agent. The composite use of the dust suppressant and the sodium silicate as the moisture absorbent can increase the permeability and the evaporation resistance of a dust suppressant solution to pavement dust, achieve the effects of moisturizing and freezing resistance in winter, and enable the dust suppressant to have the functions of wetting, bonding, condensing, moisturizing and the like. The dust suppressant is non-toxic and harmless, has neutral pH value, and has no adverse effect on limestone performance and long-term use of equipment. Not only can reduce mine transportation road surface raise dust in a large number, improve mining area environment, water resource and labour can also very big sparingly.

In particular, the invention selects cheap, easily degradable and pollution-free vegetable gum as the main carrier of the graft copolymer, and utilizes the viscosity of guar gum and xanthan gum, and acrylamide is selected to enhance the water retention property of the product. The reaction mechanism is that the initiator initiates-OH of xanthan gum and guar gum to remove hydrogen ions under a certain condition to form primary free radicals, and carbon-carbon double bonds in acrylamide are broken and combined with hydroxyl free radicals to generate a repeatedly superposed three-dimensional network space structure. Overall structure is stable, mechanical properties is strong, can effectually adhere the dust, prevents that the dust from flying upward.

Drawings

In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the embodiments or the prior art will be briefly described below, it is obvious that the drawings in the following description are only embodiments of the present invention, and for those skilled in the art, other drawings can be obtained according to the provided drawings without creative efforts.

FIG. 1 is a schematic diagram of a synthesis process according to the present invention;

FIG. 2 is an infrared diagram of the composite dust suppressant for the open-air limestone mine road dust;

FIG. 3 is an SEM image of a surface of open-air limestone mine road dust sprayed with a dust suppressant;

fig. 4 is a thermogravimetric graph of the composite dust suppressant for the open-air limestone mine road raise dust.

Detailed Description

The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

The required medicament is a conventional experimental medicament purchased from a market channel; the unrecited experimental method is a conventional experimental method, and is not described in detail herein.

Example 1

A composite dust suppressant for opencast limestone mine road dust emission comprises the following components in percentage by mass:

the binder is Guar Gum (GG) 0.02% and Xanthan Gum (XG) 0.08%, the grafting monomer is Acrylamide (AM) 0.2%, the wetting agent is Sodium Dodecyl Benzene Sulfonate (SDBS) 0.2%, and the moisture absorbent is sodium silicate (Na) ₂ SiO ₃ )5 percent of initiator is 0.025 percent of potassium persulfate (KPS), and the product is crosslinkedThe agent is N, N' -Methylene Bisacrylamide (MBA) 0.025% and deionized water 94.45%.

The preparation method comprises the following steps:

(1) 0.02g of guar gum and 0.08g of xanthan gum are weighed and dissolved in 94.45ml of deionized water, and stirred for 30min at constant temperature of 25 ℃ by using a magnetic stirrer to obtain a grafting mixed substrate.

(2) Slowly adding 0.025g of initiator while stirring, and stirring at a constant temperature water bath of 60 ℃ for 30min at a medium speed to obtain a material A.

The medium-speed stirring speed is 900 r/min.

(3) 0.2g of acrylamide powder was weighed, added to the solution, reacted for 30min, and nitrogen was bubbled into the beaker at a rate of 5mL/min to obtain material B.

(4) 0.025g of cross-linking agent was slowly added to the solution to initiate graft polymerization, and the reaction was maintained at 60 ℃ for 1 hour to obtain a graft polymerization product.

(5) 0.2g of wetting agent and 5g of moisture absorbent are weighed and uniformly sprinkled into the copolymer solution in sequence, and the temperature in the whole reaction process is controlled between 25 ℃, so that a material C is obtained.

(6) Adding a certain amount of oxalic acid to adjust the pH value to be neutral, thus obtaining the finished product.

Example 2

A composite dust suppressant for opencast limestone mine road raise dust comprises the following components in percentage by mass:

the binder is Guar Gum (GG) 0.03% and Xanthan Gum (XG) 0.07%, the grafting monomer is Acrylamide (AM) 0.4%, the wetting agent is Sodium Dodecyl Benzene Sulfonate (SDBS) 0.4%, and the moisture absorbent is sodium silicate (Na) ₂ SiO ₃ )10 percent, 0.025 percent of potassium persulfate (KPS) as an initiator, 0.025 percent of N, N' -methylene-bis-acrylamide (MBA) as a cross-linking agent and 89.05 percent of deionized water.

The preparation method is the same as example 1.

Example 3

the binder comprises Guar Gum (GG) 0.05% and Xanthan Gum (XG) 0.05%, and the grafting monomer comprises Acrylamide (AM) 0.6%The wetting agent is Sodium Dodecyl Benzene Sulfonate (SDBS) 0.6%, and the moisture absorbent is sodium silicate (Na) ₂ SiO ₃ )15 percent, 0.025 percent of potassium persulfate (KPS) as an initiator, 0.025 percent of N, N' -methylene-bis-acrylamide (MBA) as a cross-linking agent and 83.65 percent of deionized water.

The preparation method is the same as example 1.

Example 4

the binder is Guar Gum (GG) 0.07% and Xanthan Gum (XG) 0.03%, the grafting monomer is Acrylamide (AM) 0.4%, the wetting agent is fatty alcohol-polyoxyethylene ether (AEO-9) 0.4%, and the moisture absorbent is sodium silicate (Na) ₂ SiO ₃ )10 percent, 0.025 percent of potassium persulfate (KPS) as an initiator, 0.025 percent of N, N' -methylene-bis-acrylamide (MBA) as a cross-linking agent and 89.05 percent of deionized water.

The preparation method is the same as example 1.

Example 5

the binder is Guar Gum (GG) 0.08% and Xanthan Gum (XG) 0.02%, the grafting monomer is Acrylamide (AM) 0.4%, the wetting agent is dodecyl dimethyl betaine (BS-12) 0.4%, and the moisture absorbent is sodium silicate (Na) ₂ SiO ₃ )10 percent, 0.025 percent of potassium persulfate (KPS) as an initiator, 0.025 percent of N, N' -methylene-bis-acrylamide (MBA) as a cross-linking agent and 89.05 percent of deionized water.

The preparation method is the same as example 1.

Experiment 1

The performance of the dust suppressant prepared in the examples 1 to 5 is detected, and the detection indexes are viscosity, compressive strength of a cured film and permeability. The detection method comprises the following steps:

and (3) viscosity measurement: the measurement was carried out using a rotor No. 0 of an NDJ-1 rotational viscometer. First, 20ml of the solution to be tested is poured into an external test cylinder (with a bottom), and the rotating speed is adjusted from large to small in the measurement process because the viscosity value of the dust suppressant solution is unknown. During testing, 3 values are read in sequence, the average value is taken as the viscosity of the dust suppressant, and the environmental temperature is recorded. The temperature of the dust suppressant solution was maintained at 25 ℃.

Testing the compressive strength of the cured film: 60g of a road dust sample of an open-air limestone mine with a particle size of less than 200 mesh was weighed and 40ml of the prepared solution of examples 1 to 5 was added. After the mixture was uniformly stirred, it was placed in a cylindrical mold having a diameter of 5cm, the mold was placed in a 50 ° vacuum drying oven, dried for 5 days, and after complete drying, the compressive strength of the shell was tested. And a universal testing machine is selected for measuring the compressive strength, the loading speed is selected to be 0.5mm/min, a standard uniaxial compression test is carried out, the test is repeated for 3 times, and the average value of the 3 tests is taken as the strength value of the test piece.

And (3) permeability testing: the permeability test of the dust suppressant prepared in examples 1 to 5 was carried out by first taking 5 parts of an appropriate amount of road dust sample of open-air limestone mine sieved (200 mesh), placing it in a glass tube, vibrating and tamping it to make the height of the fine soil particles contained in the glass tube greater than 30mm, then fixing it on a vertical plate, finally sucking 2ml of the dust suppressant solution prepared in examples 1 to 5 by a burette, slowly dropping it into the glass tube containing the dust particles, and recording the time required for the solution to penetrate to a certain depth (30mm) during titration by a stopwatch.

The results are shown in Table 1.

TABLE 1 dust suppressant Performance test results

Examples	Viscosity (mPa. s)	Compressive strength of cured film (KPa)	Penetration time (min)
				Example 1	15.6	292	18.5
Example 2	19.8	475	18.65
				Example 3	22.8	495	19.2
Example 4	18.9	375	18.03
				Example 5	13.5	258	16

In practical application, the viscosity factor has obvious influence on the spreading and permeation speed of the solution, the requirement on a spraying device is lower for the viscosity value (5-30 mpa · s), the solution is easy to atomize during spraying, and the solution is uniformly dispersed to form a more stable bonding layer. Wherein the viscosity exceeding 20 mPas results in a decrease in solution permeability and an increase in permeation time. A viscosity of less than 10 mPas results in poor adhesion. It can be seen from Table 1 that the viscosity values of examples 1 to 5 are all within the appropriate range. In addition, after the dust suppressant is sprayed, the penetration time difference is small in the examples 1 to 5, the dust wetting performance is good, the compressive strength of the formed bonding layer can effectively meet the requirement of the solidification dustproof effect of the open-air coal pile, and the whole experimental data shows that the compressive strength of the bonding layer is continuously improved along with the increase of the mass fraction of each component.

When the dust inhibitor is used in the concrete implementation, the raw materials are firstly mixed and stirred uniformly according to the proportion, and then the obtained mixed solution is sprayed on the surface of the mineral powder, preferably 2L of the dust inhibitor is sprayed per square meter. Tests show that compared with a commercially available dust inhibitor (purchased from a gallery platinum nano environment-friendly technology), the product provided by the invention is moderate in viscosity, can realize mist spraying, is good in permeability, can form a bonding layer with the thickness of 22mm, and has great advantages in viscosity, permeability and spraying uniformity. In the actual application process, the open-air limestone mine road dust can be effectively avoided.

The embodiments in the present description are described in a progressive manner, each embodiment focuses on differences from other embodiments, and the same and similar parts among the embodiments are referred to each other.

The previous description of the disclosed embodiments is provided to enable any person skilled in the art to make or use the present invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the generic principles defined herein may be applied to other embodiments without departing from the spirit or scope of the invention. Thus, the present invention is not intended to be limited to the embodiments shown herein but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. The composite dust suppressant for the dust emission of the open-air limestone mine road is characterized by comprising, by mass, 0.02% -0.1% of guar gum, 0.02% -0.1% of xanthan gum, 0.2% -0.6% of acrylamide, 0.2% -0.6% of wetting agent, 5% -15% of moisture absorbent, 0.01% -0.025% of initiator, 0.01% -0.025% of cross-linking agent and 83.55% -94.54% of deionized water.

2. The compound dust suppressant for opencast limestone mine road dust according to claim 1, wherein the wetting agent is one of sodium dodecyl benzene sulfonate, fatty alcohol-polyoxyethylene ether and dodecyl dimethyl betaine.

3. The compound dust suppressant for opencast limestone mine road raise dust according to claim 1, wherein the moisture absorbent is sodium silicate.

4. The compound dust suppressant for opencast limestone mine road raise dust according to claim 1, wherein the initiator is potassium persulfate.

5. The compound dust suppressant for opencast limestone mine road dust according to claim 1, wherein the cross-linking agent is N, N' -methylenebisacrylamide.

6. A preparation method of a compound dust suppressant for opencast limestone mine road dust emission is characterized by comprising the following steps:

7. The production method according to claim 6, wherein the mass concentration of the graft mixed substrate solution after dissolution in step (1) is 0.1%; stirring for 30min at 25 deg.C.

8. The method of claim 6, wherein the parameters of moderate speed stirring in step (2): the stirring speed is 300-; the reaction temperature was 60 ℃ and the initiation time was 30 min.

9. The method according to claim 6, wherein the nitrogen is introduced at a rate of 4 to 6mL/min in the step (3); the reaction parameters are 60 ℃ for 30 min.

10. The method according to claim 6, wherein the reaction temperature in the step (4) is 60 ℃ and the reaction time is 1 hour.

11. The method according to claim 6, wherein the stirring time in the step (5) is 30 min; the temperature of the whole reaction process is controlled at 25 ℃.

12. The method according to claim 6, wherein oxalic acid is used to adjust the pH in step (6).