Dust Suppression Research Articles

SELECTION OF COMPLEX ACTION SOLUTION AND JUSTIFICATION OF ITS SPECIFIC CONSUMPTION FOR MOISTENING OF BLASTED SULFIDE ORE PILES PRONE TO SPONTANEOUS COMBUSTION

At mining of minerals by an open-cut method with the use of highly productive mining equipment the contamination of the environment by dust emitted during various mining works takes place. Especially, at excavation of rock mass without application of means of dust suppression, the most intensive dust emission is observed. The main way to reduce dust emission is to wet the rock mass. However, the fight against dust is complicated during the development of sulfide ores prone to spontaneous combustion. The matter is that water may intensify the process of oxidation and self-heating of sulfide ores in the pile. In this connection in such conditions the traditional method of hydro-dusting cannot be used as it takes place in open pits, mined out in normal mining and geological conditions. Therefore, when developing sulfide ores prone to spontaneous combustion, for dampening it is recommended to use solutions having along with the effectiveness of dedusting and antioxidant properties, i.e. complex action. The expression for determining the specific flow rate of fluid (q), necessary to reduce dustiness to MPC is proposed. The equation for determining the moisture content of the rock mass at a depth corresponding to a certain point in time is proposed. The solution of this equation has allowed to receive the formula, allowing at known values of parameters of height of humidified heap H, m; maximum humidity of ore φm, %; natural humidity φ_e %; volume weight, kg/m3, characterized by relative constancy for the specific conditions of the pit, to determine approximately the specific consumption of the solution for its penetration to the center of self-ignition, depending on the change in the depth of the center. For practical use the highest calculated value of the specific flow rate of the solution, providing the reduction of air dustiness to MPC and the penetration of the solution to the center of self-heating, is taken.

Numerical simulation study on atomization rule and dust removal effect of surface-active dust suppressants.

Spray dust reduction is a common dust control process in coal mines. However, the actual efficiency of spray dust reduction in a coal mine is low due to poor coal wettability. We select four surfactants that can greatly improve the surface activity of a dust suppressant solution. The wettability of the surfactant solution on coal dust is investigated in terms of two aspects: surface tension and contact angle. The effects of the type of surface-active dust suppressant and its concentration in the spray solution on the wetting of the coal dust and curing effects were analyzed. Numerical simulations were used to simulate spray atomization and to deduce how different types and concentrations of dust suppressant solutions affect the spray. The technical approach of the spray dust reduction method was further optimized by comprehensive analysis and numerical simulations, which could provide guidance for the application of spray dust reduction in coal mines.

Synergistic interactions of microbial fuel cell and microbially induced carbonate precipitation technology with molasses as the substrate

The application of microbially induced carbonate precipitation (MICP) technology is critical, but many challenges remain. In this paper, a microbial fuel cell (MFC) is used to treat molasses wastewater, and the effluent is used as the substrate to promote the growth of urease-producing bacteria. The results showed that the maximum voltage of MFC was 500 mV, and the maximum power density was 169.86 mW/m2. The mineralization rate reached 100% on the 15th day, and the mineralized product was calcite CaCO3. According to the microbial community analysis, the unclassified_Comamondaceae, Arcobacter, and Aeromonas, which could improve the OH−, signal molecular transmission and small molecular nutrients to promote the urease activity of urease-producing bacteria. The above conclusions provide a new way to reuse molasses wastewater efficiently and to apply MICP technology in dust suppression.

Study on the dust migration law and a spray dust suppression scheme in transportation roadway

To solve the problem of excessive dust concentration in the belt transportation roadway of the mine. Numerical simulations were used to study the dust migration in the belt transportation roadway under 1.5m/s ventilation conditions. The simulation results show the process of dust ejection from the inflow chute to contamination of the whole belt transportation roadway, and the spatial distribution of dust velocity. A comprehensive dust reduction scheme of "central suppression and bilateral splitting" was designed according to the dust distribution, with simultaneous control of the infeed chute and the roadway. In practical application, pneumatic spraying greatly reduces the amount of dust in the guide chute. The misting screen has a significant effect on dust collection and segregation. The solution effectively controls the dust in the space of 20m on both sides of the transfer point, and the dust removal efficiency reaches more than 90%.

Performance optimization and mechanism analysis of applied Enteromorpha-based composite dust suppressant.

In order to solve the problem of environmental pollution caused by the escape of coal dust in open-pit coal mines, a composite dust suppressant was prepared from Enteromorpha, and the preparation factors (water-soluble polymer, temperature, solid content and surfactant) were optimized. The mechanism of dust suppression and the possibility of large-scale field application were discussed. The research results on the related properties of dust suppressants showed that the performance of Enteromorpha-based dust suppressants prepared by this method was excellent compared with similar studies. Among them, polyacrylamide (PAM) Enteromorpha-based dust suppressant had the best performance, with viscosity of 25.1mPas and surface tension of 27.05mN/m. Moreover, PAM Enteromorpha-based dust suppressant had the best effect, with the mass loss of 2.94% under the wind speed of 10m/s and the coal dust loss rate of 4.6% after rain erosion, and it had strong water retention performance. Through the discussion of dust suppression mechanism, it was found that the mechanical entangled network structure with hydrogen bonds as nodes was formed after the graft copolymerization of PAM and Enteromorpha. It had high permeability and good adhesion. After quickly wetting coal dust, it formed a dense package for coal dust. The field experiment also showed that the use of Enteromorpha-based dust suppressant can effectively inhibit the escape of coal dust. From the point of view of economy and efficiency, Enteromorpha can save 30% of the material cost and the dust suppression efficiency can reach 89-94%. Therefore, the Enteromorpha-based dust suppressant may stably suppress coal dust on the basis of reducing the cost.

Effectiveness of Protein and Polysaccharide Biopolymers as Dust Suppressants on Mine Soils: Results from Wind Tunnel and Penetrometer Testing

For the dust control of barren mine soils, protein and polysaccharide biopolymers have recently shown potential as environmentally friendly alternatives to conventional dust suppressants (e.g., salt brines or petroleum-based products). However, laboratory studies that determine suitable application parameters are required for large-scale field trials. This study performed wind tunnel and pocket penetrometer tests to investigate the wind erosion and penetration resistance of treatments with different biopolymer types, concentrations (wt%), and application rates (L/m2) on two mine soils. The results demonstrate that all treatments significantly enhanced the wind erosion resistance of both tested soil types, with the biopolymer type, concentration, and application rate having a significant effect. Depending on the biopolymer type and application parameter, the wind-induced soil loss ranged from 0.86 to 423.9 g/m2 (Control = 2645.0 g/m2) for medium-grained sand and from 0.3 to 225 g/m2 (Control = 26,177.0 g/m2) for fine-grained silica sand, with the soil loss reducing as concentrations increase, until it reached a plateau concentration. For a similar performance, the tested proteins (wheat and fava bean protein) must be applied at higher concentrations than those of the polysaccharides (xanthan gum, corn starch, and carboxymethylcellulose). Spearman rank correlation revealed a moderate-to-strong negative correlation between soil loss (g/m2) and penetration resistance (N), rendering the pocket penetrometer a rapid, low-cost, and indirect method for evaluating potential dust suppressants. This research contributes to evaluating biopolymers as alternatives to traditional dust suppressants for controlling dust emissions on barren surfaces. Biopolymers are biodegradable and can be sourced regionally at a relatively low cost, reducing the environmental impact and expenses associated with dust suppression.

Synthesis of cardanol grafted hydrophilic polymers and its mechanism of coal dust inhibition

A novel hygroscopic sodium cardanol polyoxyethylene ether sulfate (SCPES) dust suppressant was synthesized via graft copolymerization, sulfonation, and alkalization reactions of cardanol and polyoxyethylene. The critical micelle concentration, chemical synthesis and wetting mechanism of SCPES were investigated using pyrene fluorescence spectroscopy, Fourier transform infrared spectroscopy, quantum chemistry and molecular dynamics software. SCPES was synthesized in three steps: first, the phenolic –OH of cardanol was de-H and grafted with polyoxyethylene to form cardanol polyoxyethylene ether (CPE); second, the H atom of CPE was replaced by the –SO3H of H2SO4 to generate cardanol polyoxyethylene ether sulfate (CPES); finally, the H+ of CPES was alkalized with the OH− of NaOH to form SCPES. It was found that the active centers of the three reactions were all at the O–H bond, the activation energies were 233.66, 85.99, and − 66.91 KJ/mol, and the final composite had distinct aromatic ether (Ar–O, R–O), S–O, and S = O infrared absorption peaks, proving that SCPES had been successfully prepared. 0.10 g/L and 0.25 g/L were the critical association concentration and critical micelle concentration of SCPES, and the surface tension and contact angle at the critical micelle concentration were 33.12 mN/m and 39.5°. Compared with the H2O-lignite system, the H2O-SCPES-lignite system exhibited an increase in the total number of hydrogen bonds from 2082 to 2136, a decrease in the interaction energies from − 13863.35 kcal/mol to − 17817.77 kcal/mol, and an increase in the diffusion coefficients of H2O molecules from 0.12 to 0.73. The results indicated that the long hydrophobic tail chain in the molecular structure of SCPES was entangled with the hydrophobic sites on the coal surface, acting as intermediate carriers between water and coal to improve the wettability of coal dust, and providing a new technical means for coal dust inhibition.

Preparation and properties of modified starch-based low viscosity and high consolidation foam dust suppressant

Aiming at the high-concentration dust pollution in open-pit coal mines, a foam dust suppressant with low viscosity and consolidated coal dust is developed. In order to reduce the limited effect of binder viscosity on the foaming ability and wettability of foam, tapioca starch is oxidized with Cu2+/H2O2 System in this study to reduce the molecular weight of the polymer and prepare materials with high consolidation and low viscosity. The dust suppression performance of the sample is measured, and the microscopic adsorption mechanism of the dust suppressant is investigated by molecular dynamics simulation. The results show that the oxidized starch adhesive solution consists of 20 g tapioca starch, 0.88 ml hydrogen peroxide, 2.4 g sodium hydroxide, and 0.48 g copper sulfate, which need to be diluted to 10 times the original volume, and 1 g of surfactant (sodium fatty alcohol polyoxyethylene ether sulfate/alkyl Glycoside=1:4) is added to prepare a new foam dust suppressant. The viscosity is 2.6 mPa·s, the foaming multiple is 6.25, the contact angle is 13.73° at the first second, the hardness reaches 70.75 HA, and a dust suppression rate of 98.17% for PM10. The dust suppressant can effectively suppress coal dust.

Humic-Based Polyelectrolyte Complexes for Dust Suppression.

The present study proposes a novel application of humic substance-aminosilsesquioxane polyelectrolyte complexes (HS-ASQ) as dust suppressants. These complexes are synthesized through the reaction between humic substances (HS) and 3-aminopropyltriethoxysilane (APTES) in aqueous solution, resulting in the formation of active silanol groups that can bind to mineral surfaces and condense, forming gels. The HS-ASQ compositions were found to have a high sorption capacity for dust particles and could form coatings on their surface without cementing the dust, making them potentially useful for environmental applications. The viscosity of the HS-ASQ compositions can be controlled by adding carboxymethylcellulose (CMC), which also enhances their dust suppression abilities. Different compositions of HS-ASQ were synthesized by varying the proportions of APTES and CMC, and dust treated with these samples was assessed for its resistance to wind erosion using a laboratory-scale setup. Treatment with the HS-ASQ composition resulted in substantial reductions in PM10 and PM2.5 concentrations (particulate matter with aerodynamic diameters of 10 µm and 2.5 µm, respectively) of up to 77% and 85%, respectively, compared to the control.

Influence of Molasses on the Explosion and Decomposition Properties of the Coal Dust Deposited in Underground Mines

Coal dust endangers the health and safety of workers in underground coal mines. Therefore, developing coal dust suppressants with dust prevention and explosion-proof properties is critical. The influence of molasses on the explosion and decomposition of the coal dust deposited in underground mines was investigated using 20 L explosion experiments and thermogravimetric and differential thermal analysis (TG-DTA). Findings reveal that, first, molasses can weakly promote the explosion of coal dust at low coal dust concentrations (<400 g/m3) but has no significant effect on the explosion at high coal dust concentrations (≥400 g/m3). Second, the decomposition process of the coal dust mixed with molasses has three stages: the moisture evaporation stage (0–150 °C), the molasses decomposition stage (150–300 °C), and the coal dust decomposition stage (300–500 °C). Molasses oxidation consumes oxygen and releases heat; at low coal dust concentrations, the released heat can promote coal dust decomposition to produce combustible gas, enhancing the coal dust explosion; at high coal dust concentrations, under the co-influence of the heat generation and oxygen consumption, molasses has no effect on the coal dust explosion. This is the mechanism of which molasses influences coal dust explosions.

Suppression of anthracite dust by a composite of oppositely-charged ionic surfactants with ultra-high surface activity: Theoretical calculation and experiments

In this study, we developed composite anionic–cationic (AC) surfactants with ultra-high surface activity using sodium alpha olefin sulfonate and octadecyltrimethylammonium chloride to improve the wettability and dust suppression efficiency of coal dust. Moreover, we investigated the synergistic suppression mechanisms of AC surfactant compounds at a molecular level. The thermodynamics of the self-assembly suggested that the surfactant molecules in the composite solution form a flexible alternating anion–cation bilayer. The analysis of the critical micelle concentration (CMC), surface tension (24.121 mN·m−1), contact angle (35.14°) and settling time (18 s) of the composite surfactant solution proved the superior performance of our composite surfactants compared to the monomeric alternatives, resulting in enhanced wettability owing to an ultra-high surface activity. Fourier transform infrared spectroscopy (FTIR) and X-ray photoelectron spectroscopy (XPS) experiments revealed an increased number of hydrophilic groups on the surface of the composite surfactant-treated anthracite, explaining the microscopic mechanism behind the high wettability induced by the composite surfactant. The specific surface area and pore size distribution of anthracite before and after dust suppressant treatment were calculated, and it was concluded that the dust suppressant was adsorbed on the surface and in the pores of the anthracite. In addition, the microscopic external morphology of the anthracite was shown by scanning electron microscopy (SEM), and it was found that the dust suppressant showed filling and aggregation behavior. Wind erosion and evaporation resistance experimental results show that dust suppressant-treated coal dust has enhanced water retention and wind resistance. Our findings indicate that ionic surfactants with oppositely charged compounds are promising high-efficiency dust suppressants, laying the foundation for safe coal mining and providing a theoretical background for a broad range of applications, such as haze control.

Experimental study on ratio optimization and application of improved bonded dust suppressant based on wetting effect

ABSTRACT Traditional bonded dust suppressants have high viscosity, insufficient fluidity and poor permeability problems, which is adverse to the formation of a continuous and stable solidified layer of dust suppressant solution on the surface of a dust pile. Gemini surfactant has efficient wetting performance and environmental protection performance, it is introduced as a wetting component to improve the flow and penetration performance of bonded dust suppressant solution, polymer absorbent resin (SAP) and sodium carboxymethyl starch (CMS) were selected as the main components of dust suppressant. A proportioning optimization model was constructed based on response surface methodology (RSM), and the concentration of each dust suppression component was selected as the independent variable, water loss rate, moisture retention rate, wind erosion rate and solution viscosity were chosen as the dependent variables in this model. The optimal formulation of the improved bonded dust suppressant was obtained by analyzing the laboratory experiments and field tests data. The results show that the effective time (≥15d) of the newly developed dust suppressant is 45 times longer than that of pure water (≈1/3d), and 1.875 times longer than that of the comparative dust suppressant (8d), the comprehensive cost is 27.36% lower than that of the similar dust suppressant product for mining enterprises. Implications: This paper presents the research idea of optimizing the bonded dust suppressant based on the improvement of wetting performance. And the paper used response surface method to obtain a wetting and bonding composite dust suppressant formulation. The field test shows that the dust suppressant has good dust suppression performance and economic benefits. This study laid the foundation for the development of new and efficient dust suppressants, and had important theoretical and application values for reducing dust environmental hazards and preventing occupational diseases.

Study on synthesis of environmentally-friendly polymer dust suppressant based on graft modification

In order to solve the dust problem caused by coal accumulation in the coal yard, a novel environmentally-friendly polymer dust suppressant was synthesized by graft copolymerization using sodium alginate (SA) and sodium carboxymethyl cellulose (CMC) as raw materials. Single factor experiments were carried out to determine the optimal synthesis conditions of SA-CMC, taking the viscosity and surface tension as the performance indicators. Under the optimal formulation, the viscosity was 80 mPa·s and the surface tension was 36.541 mN/m. Aiming to optimize the wetting property and resistance to evaporation of SA-CMC, the SA-CMC was combined with the water retention agent CMCS and the surfactant SDBS to obtain the composite dust suppressant (SA-CMC/CMCS). Fourier transform infrared spectroscopy (FTIR) and X-ray diffraction (XRD) were used to analyze the reaction process. Scanning electron microscope (SEM) was used to characterize the micro-structures of the cured layer on the coal dust surface after the dust suppressant spraying. The product performance test results showed that the dust suppressant had the characteristics of water absorption and water retention. The dust suppressant was sprayed on the surface of the coal dust to form a cured layer with high compressive strength, the bearing pressure of the cured layer was 43 N, and the dust suppression rate was as high as 99% under the strong wind (12 m/s) erosion conditions. Compared with water, the dust suppressant prepared in this paper has a better protection effect on coal dust and other forms of dust.

Wetting behavior during impacting bituminous coal surface for dust suppression droplets of fatty alcohol polyoxyethylene ether.

The wetting behavior of droplets during impacting coal surface widely exists in the dust control process. Understanding the effect of surfactants on the diffusion of water droplets on coal surface is critical. To study the effect of fatty alcohol polyoxyethylene ether (AEO) on the dynamic wetting behavior of droplets on bituminous coal surface, a high-speed camera is used to record the impact process of ultrapure water droplets and three different molecular weight AEO solution droplets. A dynamic evaluation index, dimensionless spreading coefficient ([Formula: see text]), is used to evaluate the dynamic wetting process. The research results show that maximum dimensionless spreading coefficient ([Formula: see text]) of AEO-3, AEO-6, and AEO-9 droplets is greater than that of ultrapure water droplets. With the increase of impact velocity, the [Formula: see text] increases, but the required time decreases. Moderately increasing the impact velocity is conducive to promoting the spreading of droplets on the coal surface. Below the critical micelle concentration (CMC), the concentration of AEO droplets is positively correlated with the [Formula: see text] and the required time. When the polymerization degree increases, the Reynolds number ([Formula: see text]) and Weber number ([Formula: see text]) of droplets decrease, and the [Formula: see text] decreases. AEO can effectively enhance the spreading of droplets on the coal surface, but the increase in polymerization degree can inhibit this process. Viscous force hinders droplet spreading during droplet interaction with the coal surface, and surface tension promotes droplet retraction. Under the experimental conditions of this paper ([Formula: see text], [Formula: see text]), there is a power exponential relationship between [Formula: see text] and [Formula: see text].

Study on coupling chelating agent and surfactant to enhance coal wettability: Experimental and theoretical discussion

To further enhance the impact of water injection and dust reduction in the deep mining process of the coal mine, an efficient dust suppressant for water injection was synthesized by coupling a chelating agent and a surfactant. The optimal composition solution was determined by surface tension, pre-treatment settling time and contact angle. The experimental results display that the composite solution (0.20 wt%) of Tetrasodium iminodisuccinate (IDS) and Sodium dodecyl sulfate surfactant (SDS) has the best wetting influence on the coal. Under this condition, the surface tension, contact angle and settling time are 23.69 mN/m, 25.72° and 48 s, respectively. FTIR tests exhibit that the proportion of hydrophilic functional groups in the coal sample treated by IDS and SDS composite solution is the highest, reaching 94.23 %. The results of particle size distribution tests show that IDS and SDS composite solution effectively reduces the dust production capacity of the coal body. In addition, the synergistic mechanism of IDS and SDS molecules is discussed from two aspects: Enhancing the pore fluidity and improving the hydrophilicity of coal. In this study, the wetting effect of the dust suppressant is better than traditional surfactants, and the results have important reference significance for improving the water injection effect.

Study on the performance and mechanism of extracellular polymer substances (EPS) in dust suppression

Microbial dust suppressants are a green method to prevent and control coal dust, but the role of extracellular polymer substances (EPS) has rarely been studied. Therefore, this paper studied the effect of different EPS concentrations (0, 0.05%, 0.10%, and 0.15% w/v) on dust suppression. The results showed that the dust suppression efficiency increased with the EPS concentration. When the EPS concentration reached 0.15%, the evaporation resistance and wind erosion resistance of coal dust were improved by 37.5% and 89.0%, respectively, compared with water-treated samples (p < 0.05). The contact angle of EPS-added samples was lower than that of water-treated samples and decreased to 57.35° at the highest concentration (0.15%), indicating that EPS enhanced the wettability and reduced the surface tension. Furthermore, changes in the protein and polysaccharide contents in EPS before and after dust suppression showed that the adhesion effect of polysaccharides was greater during dust suppression.

Experimental and numerical analysis of hopper dust suppression during discharge of free falling bulk solids

Experimental and numerical analysis of hopper dust suppression during discharge of free falling bulk solids

Research on performance of composite dust suppressant for mining based on modified soybean protein isolate

Research on performance of composite dust suppressant for mining based on modified soybean protein isolate

Numerical Simulation and Experiment of Dust Suppression Device of Peanut Whole-Feed Combine Using Computational Fluid Dynamics

Peanut whole-feed combines discharge a large amount of dust while harvesting, causing serious air pollution and detrimental environmental change. To reduce the dust emission from peanut whole-feed combines, a cyclone separation dust suppression device for peanut whole-feed combines was proposed in this study. A three-dimensional computational fluid dynamics (CFD) model coupled with dust particles and dust emission airflow was established to simulate the effect of a dust suppression device on capturing dust particles. Then, the effectiveness of the dust suppression device was verified by a dust suppression test system on a peanut whole-feed combine. The results show that when the inlet wind velocity of the dust suppression device increased from 15 m/s to 25 m/s, the separation efficiency of the measured value fluctuated between 90.79% and 96.07%, while the simulated value fluctuated between 95.18% and 96.59%. Moreover, the particle size of the discharged dust particles was significantly reduced under the action of the dust suppression device. The discharged dust particle size constant of the measured value was 8.6 μm, while the simulated value was 5.1 μm. The study methods and results can provide a reference for the dust suppression optimization of peanut whole-feed combines and similar agricultural machines.

Synthesis and performance determination of a glycosylated modified covalent polymer dust suppressant

Traditional polymer dust suppressants are limited due to environmental pollution, while polymer gels have attracted attention due to the advantages of environmental protection and good biocompatibility. The purpose of this research is to prepare a new type of dust suppressant with a gel network structure, which was synthesized from soybean protein isolate and glycosylated with xanthan gum. The experimental results showed that the product obtained by reacting 0.2 % xanthan gum and 0.1 % soybean protein isolate at 90 °C for 4 h has the best binding effect on coal dust, and the coal husk hardness can reach 83 HA. The microscopic reaction and structure of the product were analyzed by infrared spectroscopy, X-ray diffractometer, and scanning electron microscope, and the results revealed the structural change and specific reaction process of the product. In addition, through molecular dynamics simulation, the dust suppression effect was confirmed and the mechanism of action between dust suppressant and coal was revealed. The performance test of the dust suppressant showed that its viscosity is 23.4 mPa·s, the contact angle at 1 s is 10.01°, the PM10 dust suppression efficiency can reach 98.10 %, the water retention is 44.44 % higher than that of water, and thermal stability is improved.