An Innovative Green Dust Suppressant for Dry Climate Mining Areas in a Copper–Nickel Mine: Integration of Moisture Retention and Erosion Resistance

Abstract

Mine ramps, serving as a critical transportation hub in underground mining activities, are beset by severe issues of dust pollution and secondary dust generation. While dust suppressants are more efficient than the commonly used sprinkling methods in mines, traditional single-function dust suppressants are inadequate for the complex application environment of mine ramps. Building on the development of conventional single-function dust suppressants, this research optimized the components of bonding, wetting, and moisturizing agents. Through single-factor optimization experiments, a comparison was made of the surface tension water retention property and viscosity of diverse materials, thus enabling the identification of the primary components of the dust suppressant. By means of synergistic antagonism experiments, the optimal combination of the wetting agent and bonding agent with excellent synergy was ascertained. Ultimately, the wind erosion resistance and rolling resistance were measured through three-factor orthogonal experiments, and the optimal ratio of the dust suppressant was established. Specifically, fenugreek gum (FG) was selected as the bonding agent, cane sugar (CS) as the moisturizing agent, and alkyl phenol polyoxyethylene ether (Op-10) as the wetting agent. The research findings demonstrate that the optimal ratio of dust suppressant is 0.3 wt% fenugreek gum (FG) + 0.06 wt% alkyl phenol polyoxyethylene ether (Op-10) + 3 wt% cane sugar (CS). Under these conditions, the dust fixation rate can reach up to 97~98% at a wind speed of 8 m/s. The maximum rolling resistance can reach 65~73% after grinding the samples for 1 min. The surface tension of the solution is 13.74 mN/m, and the wetting performance improved by 81% compared to pure water. This dust suppressant is of great significance for improving the working environment of workers and ensuring the sustainable development of the mining industry.

1. Introduction

In metal mines, substantial dust is generated during various stages such as extraction and transportation [1,2]. The underground ramp, the main route for vehicle transport and worker movement (Figure 1), frequently accumulates considerable dust deposits [3,4]. These dust particles are easily resuspended by vehicular activity and airflow, generating secondary dust [4,5,6]. Compared to open environments, such as highways, the confined nature of underground spaces amplifies the effects of vehicle-induced airflow, significantly increasing dust resuspension and leading to elevated dust concentrations within transport tunnels [7,8]. Such high dust levels pose serious occupational health risks to the respiratory systems of workers [9,10] while accelerating machinery deterioration [11].

Addressing the challenges of dust pollution and secondary dust removal on ramp surfaces has led to the development of both physical and chemical dust suppression methods [12,13]. Physical approaches, such as spraying and water curtain purification [14], demonstrate limited effectiveness due to the hydrophobic nature of dust particles [15,16] and necessitate excessive water consumption. To improve these shortcomings, research has been conducted on chemical dust suppressants. However, as research has progressed, the limitations and deficiencies of single-function dust suppressants have also been considered. Wetting-type dust suppressants that use refinery waste chemicals as the primary wetting agents have weak adhesion and are prone to causing secondary dust [17]. Hygroscopic inorganic salt dust suppressants have been developed for good moisture retention, but they can harm soil and plants and are corrosive to equipment [18,19]. Traditional adhesive dust suppressant has limitations of poor fluidity [20] and weak permeability, which makes it difficult to form a dense crust on thick dust layers [21]. Biological dust suppressants, while ensuring a certain level of dust suppression efficacy, also exhibit excellent degradability and environmental friendliness. Jin et al. investigated a dust suppressant in which soybean protein isolate (SPI) was modified in the presence of sodium carboxymethyl cellulose and sodium silicate using an anionic surfactant (sodium dodecyl sulfate, SDS). They found that SPI at an appropriate concentration could enhance the binding ability of the protein-based dust suppressant on coal dust particles [22]. However, the high cost of protein-based suppressants renders them impractical for mining applications [23]. In contrast, biological glues are inexpensive and readily available natural polymers. Their chemical structures are rich in polysaccharides and soluble cellulose, which contain abundant hydrophilic groups that react with water to form hydrophilic colloids [24,25,26]. These components are rich in hydrophilic groups that can react with water to form hydrophilic colloids [27,28], and the aqueous solution also possesses a certain viscosity. Furthermore, these compounds demonstrate environmental compatibility through their non-toxic nature and application as food additives [29], establishing potential as sustainable adhesive and moisturizing agents. Several researchers have developed dust suppressants based on these properties, primarily based on biological glue. Lai synthesized a biopolymer dust suppressant (PDS) by mixing acrylic acid (A.A.), acrylamide (AAM), and oxidized starch under microwave irradiation, utilizing its agglomeration and hygroscopic properties to suppress dust [30]. Similarly, Chen and Zhang explored using guar gum as a dust suppressant and observed that guar gum interacts with dust particles to form a coating around them, thereby promoting dust agglomeration [31,32]. However, current studies have predominantly focused on evaluating individual properties of dust suppressants (such as bonding capacity). At the same time, systematic investigations of their overall performance—encompassing wetting, moisturizing, adhesion, wind erosion resistance, and compaction resistance—remain relatively limited. Moreover, most existing dust suppressants are designed for coal dust, with few studies addressing their effectiveness for metal mine dust.

Leveraging the advantageous properties of biological glue, an environmentally friendly dust suppressant has been developed that is cost effective, multifunctional, and suitable for use in metal mines (copper–nickel mines). Optimization experiments were conducted to compare the surface tension, viscosity, and water retention properties of different materials through single-component testing. Additionally, synergistic antagonism experiments and multi-component, three-factor, three-level orthogonal compounding tests were performed to determine the optimal concentration of the dust suppressant formulation. Finally, the dust suppression efficacy of the optimized formulation was comprehensively evaluated by assessing its rolling resistance and wind erosion resistance (Figure 2). By utilizing the unique properties of biological glue, the developed dust suppressant addresses issues such as secondary dust generation, poor adhesion, and environmental harm, thereby providing a more sustainable and effective solution for dust control in underground mining environments.

2. Materials and Methods

2.1. Selection and Treatment of Dust Samples

The dust sample used in the present study was collected from the Kalatunke Mine in Xinjiang, and its main composition is copper–nickel ore. Samples were gathered from the 926 ramps, specifically from the road center compression zone and the dust accumulation areas on both sides of the road. The samples were placed in an oven at 80 °C and dried for 2 h. Following this, the samples were sieved using a vibrating screen (Bo Rui Test Instrument Factory, Shangyu District, Shaoxing City, Zhejiang Province, China) to obtain experimental dust (200 mesh, 74 μm) [33].

To directly assess the particle size distribution of raw dust (untreated), a Mastersizer 3000 laser particle size analyzer (Shanghai SibG Instrument System Co., Ltd., Shanghai, China) was employed for analysis (Figure 3) [34,35,36].

2.2. Optimization Experiment of Wetting Agent Components

Due to the negatively charged surface of mine dust, cationic surfactants, which process hydrophilic groups carrying a positive charge, are electrostatically attracted to and adsorb onto the dust surface [37]. This interaction causes the hydrophobic groups to protrude outward, hindering the wetting of the mine dust [38]. Therefore, the performance, environmental impact, and cost of surfactants were considered, leading to the selection of 4 anionic and 4 nonionic surfactants for screening the wetting agents. The specific details of these surfactants are presented in

Table 1. Surfactant material information sheet.

Type	Name	Character	Environmental Impact	Cost (CNY/t)
Anionic type	Secondary alkyl sodium sulfonate (SAS-60)	Light yellow oily liquid	Good biodegradability	16,700
Anionic type	Sodium talkenyl sulfonate (AOS)	White solid powder	Low toxicity, mild, low irritation, good biodegradability	11,000
Anionic type	Fatty acid methyl ester ethoxide sulfonate (FMES)	Light yellow oily liquid	Good resistance to hard water and low temperature flow	15,000
Anionic type	Sodium fatty alcohol polyoxyethylene ether sulfate (AES)	Transparent liquid	Good hard water resistance and biodegradability	9360
Nonionic type	Oleate polyoxyethylene ester (PEG-400)	Light yellowish liquid	Environmentally friendly and non-toxic	3000
Nonionic type	Fatty alcohol polyoxyethylene ether (JFC-3)	Transparent liquid	Strong acid, alkali, and hypochlorite resistance	11,500
Nonionic type	Triton 100 (T-100)	Transparent liquid	Good biodegradability	5180
Nonionic type	Op-10	Transparent liquid	The property is stable and the biological irritation is small	10,000

.

Surface tension sedimentation rate is a typical parameter used to characterize the ability of a liquid to wet dust particles [39]. Lower surface tension and faster sedimentation rate indicate a stronger ability of the liquid to wet dust particles [40]. The variation curves for surface tension and sedimentation rate, presented in Figure 4a, were obtained by testing surfactant solutions at different concentrations, expressed in weight percentage (wt%) (0.02, 0.04, 0.06, 0.08, 0.1, 0.3, 0.5 wt%).

The surface tension of the wetting agent solutions was measured at a constant temperature of 25 °C using an automatic tensiometer (Shanghai Fangrui Instrument). As demonstrated in Equation (1), improved wetting performance is manifested by decreased surface tension. The sedimentation rate of the surfactant was then assessed by measuring the rate at which dust settled to the bottom of the test tube over time. The procedure involved the following steps (Figure 4b): ① Preparation of Surfactant Solutions. Pour 10 mL of surfactant solution at various concentrations into identically sized test tubes. ② Sample Addition. Add 0.1 g of 200-mesh dust sample into each test tube. ③ Recording of Settling Time. Begin timing when the dust particles contact the liquid surface and end it once they settle entirely at the bottom of the test tube. ④ Calculate the sedimentation rate. Calculate the sedimentation rate based on the sedimentation time, as shown in Equation (2). To ensure reproducibility and statistical significance, measurements were performed in triplicate, and the mean values were calculated for subsequent analysis.

By comparing the surface tension values and settling rates, materials with lower surface tension and faster sedimentation rate were selected as candidate wetting agents for the subsequent experiment.

$$\alpha ={\displaystyle \frac{\Delta ST}{S{T}_{water}}}\times 100\%$$

(1)

$$SR={\displaystyle \frac{A}{\Delta t}}$$

(2)

where α is the increased rate of wetting performance (%); ΔST is the reduction in surface tension (mN/m); ST_water is the surface tension of water (72 mN/m); SR is the settling rate (mg/s); A is the amount of settling dust (10 mg); and Δt is the settling time (s).

2.3. Optimization Experiment of Moisturizing Agent Components

The moisturizing performance of 7 humectant materials was evaluated through a room-temperature evaporation resistance experiment [41,42], as shown in Figure 5. The specific details of the humectant materials are provided in

Table 2. Information table of moisturizing materials.

Name	Material Property
Calcium chloride (CaCl2)	Inorganic salt
Propanediol (PG)	Organic compound
Sodium pyrrolidone oxalate (PCA-Na)	Amino acid derivative
Cane sugar (CS)	Disaccharide
Sorbitol (DS)	Sugar alcohol
Sodium alginate (SAA)	Natural polysaccharide
Sodium carboxymethyl starch (CMS)	Carboxymethyl ether-modified starch

. The experimental procedure was as follows: ① Dry the dust sample. Place the 120~150-mesh dust samples in an oven and dry them continuously at 80 °C for 2 h to ensure complete water evaporation. ② Spray the moisturizing agent evenly on the dust sample. Spread 15 g of the dried dust samples evenly in a 50 mm rubber mold and uniformly spray with 7 mL of the moisturizing agent. ③ Place in a constant temperature and humidity box for the anti-evaporation experiment at normal temperature. After complete wetting, transfer the samples to a steady temperature, and set the humidity drying chamber to 20 °C and 55% relative humidity. ④ Weigh the sample and calculate the water loss rate. Weigh the samples every 12 h, and calculate the water loss rate, as shown in Equation (3). To ensure reproducibility and statistical significance, measurements were performed in triplicate, and the mean values were calculated for subsequent analysis.

$$WLR={\displaystyle \frac{M_0-M_i}{M_0}}\times 100\%$$

(3)

where WLR is the water loss rate (%); M_i is the mass of the test sample after an i-th water loss (g); and M₀ is the initial mass of the test sample, including the dust and the mass of the humectant (g).

2.4. Selection Experiment of Bonding Agent Components

Viscosity indicates the adhesive strength of a bonding agent. The higher the viscosity, the stronger the adhesive capability [43]. After conducting preliminary experiments on various biopolymeric materials and considering their cost, environmental impact, and availability, 4 biological glue solutions were ultimately selected as candidate adhesives. As shown in Figure 6, the viscosity of 4 biological glue solutions—fenugreek gum (FG), yellow dextrin (YD), sesbania gum (SG), and molasses (MO)—were measured using a viscometer (Shanghai Fangrui Instrument Co., Ltd., Shanghai, China) [44]. The experimental procedure was as follows: ① Prepare bonding agents. Prepare solutions at different concentrations for each of the 4 bonding agents. MO solutions were prepared at 5, 10, 15, 20, 25, and 30 wt% concentrations. FG solutions were prepared at 0.2, 0.25, 0.3, 0.4, and 0.5 wt% concentrations. Solutions of SG were prepared at concentrations of 0.75, 1.0, 1.5, and 2.0 wt%. YD solutions were prepared at 5, 10, 15, 20, and 25 wt% concentrations. ② Measure the viscosity of the bonding agent. Place the bonding agents into a beaker. Maintain the laboratory temperature at 20 °C. Select the No. 0 rotor and set the rotation speed to 12 revolutions per minute (r/min) for viscosity measurement. ③ Record data. Record the reading once it stabilizes.

Measurements were performed in triplicate to ensure reproducibility and statistical significance, and the mean values were calculated for subsequent analysis.

2.5. Composition and Performance Testing of Dust Suppressant

2.5.1. Synergistic Antagonism Experiment

The interactions among components in a complex system can either be synergistic or antagonistic [45]. Synergistic antagonism refers to a phenomenon in a system where the interactions among different components or factors are not merely additive but, through complex interplay, collectively generate an antagonistic or synergistic effect, resulting in an overall outcome that is less than or greater than the expected sum of the effects when each component acts individually. In other words, when multiple factors are present simultaneously, they may counteract or enhance each other, leading to a total system response that is either lower or higher than the effects observed when each factor operates independently [46]. In the research, synergistic and antagonistic interactions were evaluated to ensure that the performance of the compounded dust suppressant solution exceeded that of individual component solutions. The experimental investigation evaluated the interaction between surfactants and a bonding agent through surface tension measurements. Based on the results of the screening experiments for wetting agents and adhesives, this study selected a surfactant with excellent wetting performance and an adhesive with outstanding bonding properties to further conduct experimental investigations on their synergistic antagonistic effects. Each surfactant was prepared in aqueous solutions at precisely controlled concentrations of 0.02, 0.04, 0.06, 0.08, 0.1, 0.3, and 0.5 wt%. Initial surface tension measurements were obtained using a calibrated tensiometer under controlled ambient conditions. Measurements were performed in triplicate to ensure reproducibility and statistical significance, and the mean values were calculated for subsequent analysis.

Subsequently, a predetermined mass of FG bonding agent was introduced to each surfactant solution at an equal mass. The resulting mixtures were homogenized using a magnetic stirring apparatus until complete dissolution. Surface tension measurements were then repeated on the surfactant–FG mixtures using identical experimental parameters.

Comparative analysis of the surface tension values before and after FG addition was performed to quantitatively assess the potential synergistic or antagonistic interactions between the surfactants and the bonding agent. This systematic approach enabled the evaluation of interfacial behavior modifications induced by the molecular interaction between the selected surface-active agents and FG. The specific data are shown in

Table 3. Data table of synergistic antagonism experiment.

Ingredient		Surface Tension (mN/m)
		Not Joining FG	Joining FG
AOS (wt%)	0.02	12.56	12.65
	0.04	12.43	12.21
	0.06	12.37	12.25
	0.08	12.28	12.28
	0.10	12.51	14.12
	0.30	13.71	13.78
	0.50	14.31	13.83
SAS-60 (wt%)	0.02	11.84	12.91
	0.04	11.8	12.79
	0.06	11.75	12.08
	0.08	11.68	11.53
	0.10	11.81	11.46
	0.30	12.21	12.12
	0.50	12.25	12.19
T-100 (wt%)	0.02	14.25	13.85
	0.04	14.26	13.86
	0.06	14.31	13.95
	0.08	14.35	14.05
	0.10	14.36	14.06
	0.30	14.26	13.95
	0.50	14.36	13.84
Op-10 (wt%)	0.02	14.05	14.05
	0.04	13.85	13.85
	0.06	13.95	13.95
	0.08	13.86	13.86
	0.10	13.74	13.74
	0.30	14.26	14.26
	0.50	13.87	13.87

.

2.5.2. Multi-Component Orthogonal Experiment

The dust suppressant must be able to endure the demanding conditions of underground mine roadways [47]. Therefore, airflow impact on the dust consolidated by the dust suppressant was examined. In addition, the rolling resistance of the dust suppressant after forming a film was evaluated.

1.

wind erosion resistance experiment

Due to the complex vehicular traffic on mine roadways, the airflow generated during transportation may lift dust particles. Field investigations revealed that when mine vehicles travel 25 km/h in the tunnels, the airflow reaches approximately 8 m/s. Therefore, this study simulated the tunnel airflow environment through wind erosion experiments to evaluate the dust suppressant’s fixation rate.

As shown in Figure 7a: ① Prepare dust sample. Spread a 20 g dust sample evenly within a 50 mm rubber mold. ② Spray the dust suppressor evenly. 7.5 mL of dust suppressant solution was uniformly sprayed onto the sample at different concentrations (0.02, 0.04, 0.06, 0.08, 0.1, 0.3, 0.5 wt%). ③ Conduct wind erosion experiment. After the sample was fully wetted, it was placed in front of a fan blowing at a constant speed of 8 m/s [48]. ④ Weigh the sample and calculate the dust fixation rate. Measure the sample’s mass every 15 min and calculate the dust fixation rate as described in Equation (4). To ensure reproducibility and statistical significance, measurements were performed in triplicate, and the mean values were calculated for subsequent analysis.

$$DFR={\displaystyle \frac{M_i-M_0}{M_0}}\times 100\%$$

(4)

where DFR is the dust fixation rate (%); M₀ is the initial mass of the dust sample (g); M_i is the mass of the test sample after i-th being eroded by wind (g).

2.

Rolling resistance test

The following procedure is shown in Figure 7b: ① Dry the sample. Following the wind erosion test, dry the samples completely in an oven. Record the weight at this point as M_o. ② Roll samples with a grinding jar. Transfer the samples to a 0.5 L grinding jar containing 6~8 grinding beads of similar size. Roll them rolled for 1 min at a speed of 252 r/min. ③ Sieve the sample. Sift the ground dust samples through a standard sieve for 3~5 min, weigh the sieve residual mass, and record as M_T. ④ Calculate rolling resistance. Calculate the ratio of the sieve mass to the total original mass of the dust sample [49]. This ratio, referred to as the R-value, indicates the rolling resistance of the sample. A higher percentage of material on the sieve corresponds to a higher R-value, signifying better rolling resistance. The calculation process is shown in Equation (5). To ensure reproducibility and statistical significance, measurements were performed in triplicate, and the mean values were calculated for subsequent analysis.

$$R={\displaystyle \frac{M_T}{M_O}}\times 100\%$$

(5)

where R is the rolling resistance of the sample (%); M_T is the mass of the material on the sieve (g); and M_O is the original mass of the sample (g).

3. Results

3.1. Dust Particle Size Test Results

The particle size distribution analysis of the dust sample reveals three distinct size ranges (Figure 8). Range A (0~1.0 μm) exhibits a minimal particle concentration, predominantly distributed near 1.0 μm, indicating negligible presence of ultrafine particles. In Range B, the particle size spans from 1.0 μm to 180.0 μm, with most dust particles concentrated between approximately 10 μm and 100 μm. According to the “Workplace Airborne Dust Hygiene Standards” (GBZ 2.1-2007), the range includes both respirable dust (<10 μm) and settleable dust (>10 μm). Respirable dust can pass through the upper respiratory tract to reach the lungs and accumulate in the alveoli, while particles smaller than 5 μm are more likely to deposit within the alveoli. Over time, this deposition may lead to various pulmonary diseases, posing a significant risk to human health. Settleable dust, on the other hand, tends to settle on surfaces, including the ground and equipment, due to gravity. These deposits can be carried into equipment by the airflow generated by transport vehicles, contributing to accelerated wear and tear.

In Range C (100~3800 μm), the particle exhibits a peak around 1000 μm. These larger particles are not easily inhaled but tend to accumulate along the sides of ramps, generating secondary dust and contributing to underground environmental pollution. Therefore, the primary targets for dust suppression in this study are respirable and settleable dust particles.

3.2. Analysis of Experimental Results of Wetting Agent Optimization

3.2.1. Analysis of Surface Tension Test Results of Four Anionic and Four Nonionic Surfactants

Surface tension measurements of eight surfactants revealed significant reductions compared to water (72 mN/m at 25 °C, laboratory measured) (Figure 9). The 0.1 wt% of SAS-60 solution exhibited the maximum reduction to 12.05 mN/m; in contrast, 0.02 wt% PEG-400 solution showed the minimum reduction to 16.65 mN/m, representing improvement ranges of 76.88% to 83.26% compared to pure water, respectively. This enhanced wetting capacity results from forming stable films by anionic and nonionic surfaces, characterized by outward-oriented hydrophilic groups and inward-oriented hydrophobic groups [50]. Such molecular arrangement creates regular monomolecular or multimolecular layers at the liquid interface, reducing surface molecular force imbalances and enhancing dust particle wetting capabilities [51].

The critical micelle concentration (CMC) represents the minimum surfactant concentration required for micelles formation [52]. At CMC, solutions achieve minimum surface tension and maximum wetting ability. Concentration exceeding CMC induces micelle formation without further surface tension reduction. Anionic surfactants (Figure 9a) demonstrate CMC values of approximately 0.1 wt%, with surface tension increase above this concentration. SAS-60 and AOS maintain lower surface tension values within 0.1 wt%. Nonionic surfactants (Figure 9b) show optimal performance within 0.1 wt%. While PEG-400 and JFC-300 show continuous surface tension decreases with concentration increase, Op-10 and T-100 maintain stable, relatively low surface tensions. These characteristics identify SAS-60, AOS, Op-10, and T-100 as superior wetting agents.

3.2.2. Analysis of Sedimentation Experiment Results of Four Anions and Four Nonionic Surfactants

Figure 10 shows the results of the sedimentation experiments, which align with the findings from the surface tension tests. Among the anionic surfactants, SAS-60 and AOS demonstrate superior sedimentation effects compared to FMES and AES. Similarly, among the nonionic surfactants, Op-10 and T-100 perform better than JFC-3 and PEG-400. In general, the sedimentation effects of all eight surfactants show a positive correlation with their concentrations. Specifically, PEG-400, FMES, and AES show minimal variation in sedimentation performance across the concentration range, while SAS-60, AOS, T-100, and Op-10 consistently outperform the other surfactants at all concentrations. Notably, SAS-60 and Op-10 exhibit a marked advantage in sedimentation speed at concentrations above 0.1 wt%.

This indicates that the four surfactants have better diffusivity on dust surfaces, enabling more effective bonding with dust particles. The enhanced interaction may alter the molecular arrangement on the dust surface, promoting the formation of extensive agglomerates. These agglomerates, in turn, enhance both the permeability and wettability of the dust conglomerates, facilitating their sedimentation and improving the overall dust suppression efficiency [53,54].

3.3. Analysis of Experimental Results of Anti-Evaporation at Room Temperature

As illustrated in Figure 11, during the first 36-h period, decreasing water loss rates indicate environmental moisture absorption through hygroscopic effects and protective film formation.

The most significant reduction in the water loss rate occurred within the first 12 h. At this stage, the moisturizing agent had not yet fully penetrated the dust samples, and a complete protective film had not formed on the sample surface. Therefore, the desorption from the samples was greater than the hygroscopic effect of the moisturizing agents, leading to faster water evaporation. Beyond 36 h, all agents except SAA exhibit a slight rate increase due to enhanced moisture absorption capabilities. The seven moisturizing agents demonstrated significant moisturizing and hygroscopic effects, effectively absorbing moisture from the air, increasing the water content of the dust samples, and achieving an effective dust suppression result.

As shown in Figure 12, the anti-evaporation effects of DS, SAA, and PCA-Na are inferior to that of the other four moisturizing agents, and their required concentrations are significantly higher. From an economic and practical standpoint, these agents are not ideal for use as moisturizing agents or dust suppressants. Among the four materials with low concentrations, CaCl₂, PG, and CS exhibit comparable anti-evaporation effects. However, CaCl₂ is corrosive and poses potential risks to human skin and equipment. Furthermore, although PG shows similar anti-evaporation performance to CaCl₂ and CS at 1 wt%, its efficacy significantly diminishes at concentrations of 2 wt% and above (Figure 11), where its anti-evaporation effect is notably lower than that of both CaCl₂ and CS.

In contrast to alternative humectants, CS exhibits superior properties as a carbohydrate compound, producing no toxic byproducts during dust particle interactions. The aqueous solution of CS demonstrates specific viscosity characteristics that facilitate enhanced dust particle adhesion. Based on the comprehensive evaluation of these properties, CS has been determined to be the optimal humectant component for dust suppression applications.

3.4. Analysis of Viscosity Experimental Results

The viscosity of the solution exhibits a critical influence on dust suppression performance. Excessive viscosity reduces flowability and impedes dust penetration, while insufficient viscosity fails to achieve effective particle bonding. Through systematic spraying experiments with solutions of varying viscosities (

Table 4. Viscosity standard test table.

Concentration (%)	0.1	0.3	0.5	0.7	1.0
Viscosity (cp)	5.13	9.45	13.00	50.27	105.69

), it was determined that the solution with a viscosity of 5.13 cp exhibited good fluidity but lacked sufficient adhesive properties to meet the requirements. In contrast, the solutions with viscosities of 50.27 cp and 105.69 cp, although having higher viscosities, demonstrated poor fluidity and penetration, thereby failing to rapidly wet the dust. The solutions at 9.45 cp and 13.00 cp showed no significant difference in fluidity; however, to achieve better adhesion, the 13.00 cp solution was ultimately selected as the reference standard for the comparative analysis of four biological adhesives (Figure 13).

Analysis of the experimental results (Figure 13) demonstrates that FG and YD solutions exhibit a positive correlation between concentration and viscosity. The correlation is attributed to high water solubility, wherein increased bonding agent concentration enhances the probability and frequency of polymer molecular interactions, resulting in progressive viscosity elevation. In the concentration–viscosity relationship analysis, FG reaches 12.81 cp at 0.3 wt%, meeting dust suppressant adhesive requirements. While YD attains 11.66 cp at 25 wt%, its high concentration requirement renders it economically unfeasible for dust suppression applications.

The viscosities of SG and MO remain consistently low across all experimental concentrations, exhibiting minimal concentration dependence. This phenomenon is attributed to limited water solubility at ambient temperature, manifesting as particle characteristics impede complete dissolution, restricting molecular interactions between the biological adhesive and water molecules, thereby inhibiting viscosity development. Based on these findings, FG demonstrates superior suitability as a bonding agent, evidenced by its excellent water solubility and adhesive properties at economically viable low concentrations.

3.5. Analysis of Results of Synergistic Antagonism Experiment

The synergistic and antagonistic interactions between surfactants and FG were systematically evaluated across concentration ranges (Figure 14). The nonionic surfactants Op-10 and T-100 showed consistent synergistic effects with FG across all tested concentrations. This synergistic behavior is attributed to their nonionizing properties in aqueous solutions, which maintain solution pH stability and preserve intermolecular attractive forces. Furthermore, the distinct molecular properties of Op-10 and T-100, compared to FG solutions’ hydrophilic components, result in different surface arrangement densities. The subsequent dislocation adsorption upon mixing enhances surfactant molecular arrangement density at the solution interface, facilitating improved dust particle wetting efficiency.

In contrast, SAS-60 exhibits pronounced antagonism effects at concentrations below 0.08 wt%. This antagonism stems from FG-induced alterations in solution polarity, which modify the arrangement and density of the anionic surfactant molecules at the liquid interface, thereby disrupting intermolecular forces. While AOS demonstrated minimal synergistic effects below 0.08 wt%, concentrations exceeding this threshold produced significant antagonism, indicating overall system instability.

Surface tension analysis of the mixed solutions revealed that T-100 maintained values between 14.2 mN/m and 13.8 mN/m, while Op-10 consistently produced values below 13.8 mN/m. Comparative analysis of minimum surface tension values showed T-100 at 13.85 mN/m and Op-10 at 13.55 mN/m. Based on the comprehensive evaluation of synergistic effects and surface tension characteristics, the nonionic surfactant Op-10 was determined to be the optimal wetting agent for the application.

3.6. Analysis of Dust Suppression Agent Composition and Performance Test Results

To determine the optimal formulation of the dust suppression agent, which includes the bonding agent (FG), moisturizing agent (CS), and wetting agent (Op-10), an L₉(3³) orthogonal array experimental design was implemented to systematically investigate the effects of varying component concentrations in dust suppressant formulations. The experimental matrix consisted of three factors (A, B, and C) at three concentration levels (

Table 5. Level table of orthogonal experimental factors.

Factor	Level
	1	2	3
A (FG, wt%)	0.2	0.3	0.4
B (CS, wt%)	0.02	0.06	0.1
C (Op-10, wt%)	1	2	3

). Factor A was evaluated at 0.2, 0.3, and 0.4 wt%; factor B at 0.02, 0.06, and 0.1 wt%; and factor C at 1.00, 2.00, and 3.00 wt%.

This orthogonal array design resulted in nine distinct formulations, significantly reducing the number of experimental trials while maintaining statistical validity compared to a full factorial design. The concentration levels for each component were carefully selected based on preliminary studies and theoretical considerations to ensure optimal coverage of the experimental space [55].

Table 6. L₉(3³) orthogonal experiment table.

Samples Number	A (wt%)	B (wt%)	C (wt%)
1	0.20	0.02	1.00
2	0.20	0.06	2.00
3	0.20	0.10	3.00
4	0.30	0.02	2.00
5	0.30	0.06	3.00
6	0.30	0.10	1.00
7	0.40	0.02	3.00
8	0.40	0.06	1.00
9	0.40	0.10	2.00

presents the complete experimental matrix with the specific concentration combinations for each formulation.

3.6.1. Analysis of Experimental Results of Wind Erosion Resistance

The strength of wind erosion resistance for the dust suppressant is quantified by the dust fixation rate. Figure 15a–c illustrate the dust fixation rates of samples (Table 6 and water) with FG concentrations of 0.2 wt%, 0.3 wt%, and 0.4 wt%, respectively, while Figure 15d compares the dust fixation rates across nine different (Table 6) formulations and water. As indicated in Figure 15d, during the first 30 min, the dust fixation rates of all nine formulations and water are comparable. This outcome can be attributed to the ability of both the dust suppressants and water to wet the dust particles in this period. Consequently, only a small proportion of fine particles on the sample surface are carried away by the airflow, with the majority of the dust remaining adhered due to the increased weight resulting from the wetting effect, making it difficult for the dust to be blown away.

After 30 min, the dust fixation rate for the water-treated samples declines sharply. This occurs because water, having low evaporation resistance and cohesion, cannot maintain a stable crust once evaporated. Without the formation of a stable crust, the dust reverts to a loosely structured granular form, easily dispersed by the airflow. In contrast, the samples treated with dust suppressants demonstrate better moisture retention and evaporation resistance. The action of the bonding agent facilitates the formation of a cohesive crust on the sample surface, which binds the dust particles together and prevents their displacement by the airflow.

A comparison of Figure 15a–c reveals that the dust fixation efficiency of 0.4 wt% FG formulation does not significantly outperform that of the lower concentration formulations. Its dust fixation rate is lower than that of some of the low-concentration samples (Sample 3 and Sample 5). This can be explained by the higher viscosity of 0.4 wt% FG solution, which reduces permeability compared to lower concentrations. According to

Table 7. Change table of wind erosion resistance of dust suppressant in 75 min.

Class Number	A (wt%)	B (wt%)	C (wt%)	Wind Erosion Resistance (%)
1	0.20	0.02	1.00	97.70
2	0.20	0.06	2.00	97.45
3	0.20	0.10	3.00	98.09
4	0.30	0.02	2.00	97.72
5	0.30	0.06	3.00	97.83
6	0.30	0.10	1.00	97.46
7	0.40	0.02	3.00	97.39
8	0.40	0.06	1.00	97.59
9	0.40	0.10	2.00	97.47
water	0	0	0	95.45
k1	97.75	97.60	97.58
k2	97.67	97.62	97.55
k3	97.48	97.67	97.77
Range R	0.27	0.07	0.22
Order	A > C > B
Preference	A1	B3	C3
	0.2 wt% bonding agent	0.1 wt% wetting agent	3 wt% moisturizing agent
Optimal combination	A1B3C3

, the influence of FG on the dust fixation rate is greater than that of CS. After 45 min, the highly viscous dust suppressant struggles to wet the dust efficiently under the influence of the wetting agent, failing to form a complete and rigid shell. Instead, weaker and thinner dust clumps are formed, which disintegrate under continuous airflow, causing the dust to be blown away in clusters and resulting in a lower dust fixation rate.

To provide a more direct comparison of the dust suppressant’s efficiency in reducing wind erosion, the dust fixation rate at 75 min serves as the index for comprehensive dust suppression efficiency, as presented in Table 7 and Figure 16.

The k-value (k1–k3) reflects the impact of the concentration of each component on the dust retention rate. At the same time, the Range R indicates the contribution of each component to the dust retention rate (Table 7). According to Range R, FG content exerts the greatest influence on the dust retention rate, followed by CS content. The k-values indicate that the optimal dust suppressant formulation is A₁B₃C₃ (Sample 3), corresponding with the experimental results. It can be seen that Sample 3 represents an ideal dust suppressant when wind erosion resistance is the primary focus.

As shown in Figure 16, the dust fixation rate for samples treated with dust suppressant is significantly higher than that for water. The dust fixation rates of low-concentration FG samples (1–5) exceed those of the high-concentration FG samples (7–9). The dust retention rate generally reaches 97.5% or higher, with a peak of 98.09% at 75 min. This is attributed to the superior permeability and wetting properties of the dust suppressant, which allows it to rapidly and completely wet the dust. The adhesive molecules efficiently encapsulate the dust particles, bonding them into a cohesive mass. Additionally, the humectant absorbs moisture from the air, increasing the weight of the dust and contributing to the formation of a crust on the surface of the sample, thereby enhancing resistance to wind erosion.

3.6.2. Experimental Analysis of Rolling Resistance

Rolling resistance evaluation (Figure 17) shows values exceeding 60% for most formulations, with maximum efficiency reaching 72.9%. Formulations 4–9 exhibit enhanced resistance properties, correlating positively with FG concentration. This superior performance stems from increased bonding agent concentrations facilitating particle aggregation and structural transformation. The humectant maintains internal moisture gradients, creating a composite structure characterized by enhanced surface harness and internal flexibility.

Analysis of formulations 4–9 revealed notable variations in wear resistance performance, with formulation 6 exhibiting significantly lower durability. The component influence hierarchy on dust suppressant performance was established through comprehensive evaluation: bonding agent demonstrated the highest impact, followed by humectant, with the wetting agent showing the least influence. The inferior wear resistance of formulation 6 can be attributed to two primary factors: first, compared to formulations 7–9, which contained higher bonding agent concentrations, formulation 6 had a lower bonding agent content; second, among formulations 4–6, it contained the lowest humectant concentration. Although Sample 2 exhibited similar wear resistance to Sample 8, the overall experimental trend indicates that wear resistance is positively correlated with adhesive concentration, with adhesive concentration exerting the greatest influence on wear performance. Consequently, as a member of the low-concentration group, Sample 2 (along with Samples 1 and 3) showed significant fluctuations in wear resistance, making it difficult to ensure stable performance in practical applications; hence, this concentration combination was not considered.

The structural configuration of the remaining formulations (4–5 and 7–9) demonstrated enhanced rolling resistance properties. These five formulations emerged as optimal compositions based on rolling resistance criteria, establishing a clear correlation between component ratios and performance metrics.

3.7. Determination of the Formulation of Dust Suppressant

The research evaluated the performance of various dust suppressant formulations using two key parameters: the rolling strength and dust fixation rate. The high-concentration FG formulations (Samples 4–9) demonstrated superior compressive strength when assessed by rolling strength, indicating their effectiveness in providing structural stability. However, when wind erosion resistance was used as the reference index, Sample 3 showed the highest dust fixation rate, proving to be the most effective in retaining dust particles.

As shown in Figure 15, the dust retention performance of samples 4 and 5 was also notable, suggesting that this formulation performed well in terms of dust suppression. Based on this comprehensive evaluation, to achieve a dust suppressant formulation that balances high rolling strength and excellent dust fixation rate, the final formulation selected was 0.3 wt% FG + 0.1 wt% Op-10 + 3 wt% CS.

The optimized formulation achieves a rolling strength of 65–73%, a dust fixation rate between 97 and 98%, and a surface tension of 13.74 mN/m. Notably, the wetting performance of the solution is 81% higher than that of pure water, enhancing the overall effectiveness of dust suppression. The dust suppressant was developed under laboratory conditions specifically for a single type of mine (copper–nickel mine). Combining these characteristics ensures that the selected formulation provides both structural integrity and effective dust stabilization, making it an ideal choice for practical applications in copper–nickel mines that require robust wind erosion resistance and sustained dust suppression.

3.8. Cost Analysis of Dust Suppressant

The primary materials of the dust suppressant are FG (fenugreek gum), CS (cane sugar), and OP-10, with market prices of CNY 25,000/t for FG, CNY 3000/t for industrial CS, and CNY 10,000/t for OP-10. The calculation for the dust suppressant dosage per unit area is shown in Equation (6). It was calculated that FG = 6 g, CS = 60 g, and Op-10 = 2 g.

$$Y=C\times k$$

(6)

where Y is the material dosage per unit area (g); C is the mass concentration of the material (%); and k = 2000 represents the amount of water used per unit area (g).

The calculation for the dust suppressant spraying cost per kilometer is presented in Equation (7). It was calculated that the total cost for the dust suppressant was CNY 1401.08/km.

$$P=S\times \left({\displaystyle \sum _{i=1}^3{Y}_i\times B_i}\right)+W$$

(7)

where P represents the treatment cost per kilometer (CNY); S = 4000 denotes the area per kilometer (m²); Y_i is the dosage per unit area for each material (g); B_i is the unit price for each material (CNY); and W = 1.08 represents the total cost of water consumption per kilometer for the mine in Xinjiang. (CNY).

4. Conclusions

A novel multifunctional and eco-friendly dust suppressant was developed utilizing biological adhesive as the core component. The formulation demonstrated enhanced performance characteristics through systematic optimization of bonding agents, wetting agent, and moisturizing agent. The experimental findings yielded the following conclusions:

A new multifunctional and environmentally friendly dust suppressant formulation was developed based on biological glue, which shows superior adhesive and moisturizing properties while maintaining ecological sustainability. The primary components of the dust suppressant formulation are FG and CS. Natural high-molecular-weight polymers contain abundant hydrophilic groups that react with water to form a hydrophilic colloid. They are non-toxic, harmless, readily soluble in water, and do not generate toxic or hazardous byproducts upon hydration. Additionally, their excellent biodegradability ensures they neither irritate workers nor damage machinery. Through systematic formulation analysis, the optimal composition was determined to be 0.3 wt% FG + 0.1 wt% Op-10 + 3 wt% CS in aqueous solution.

Synergistic antagonism evaluation experiments demonstrated superior compatibility between nonionic surfactants and FG. The nonionic surfactant Op-10 exhibited optimal synergistic antagonism effects with FG solution, achieving a minimal surface tension of 13.55 mN/m.

Wind and rolling resistance tests demonstrated the formulation’s exceptional dust control capabilities. Upon drying, the suppressant forms a cohesive surface crust that immobilizes dust particles. The dust retention efficiency reached 97–98% under 8 m/s wind conditions. Mechanical stability tests revealed rolling resistance values of 65–73% after 1 min of grinding. The formulation achieved a surface tension of 13.74 mN/m, exhibiting an 81% enhancement in wetting performance compared to water. The total cost for the dust suppressant was CNY 1401.08/km.

5. Prospects of Future Study

This study developed a multifunctional, environmentally friendly dust suppressant to address the dust issues in metal mines (copper–nickel mines) and evaluated its performance. There is still room for improvement in its application. Under laboratory conditions simulating an industrial environment, we investigated factors affecting the suppressant’s wind erosion resistance and compaction resistance. Notably, some researchers have successfully applied dust suppressants in mining sites based on laboratory studies [56], thereby optimizing their formulations, while others have improved material ratios using response surface methodology [57]. In the future, on-site industrial spraying experiments can be conducted to verify the spraying efficiency of the suppressant, and various optimization methods can be combined to further refine the formulation, thereby compensating for the limitations of the current study.

Currently, most mines still employ manual water spraying for dust suppression, which is inefficient and results in uneven distribution, thus adversely affecting dust control. Therefore, establishing a dust suppression spraying system for mine tunnels is critical for improving efficiency. Some researchers have installed spraying devices on conveyor belts to achieve precise application; however, these systems only target localized areas, making them difficult to implement across the entire mine. Research on tunnel dust suppression spraying systems remains relatively scarce, and undertaking such studies would help fill this gap in the field.