Search Results (8)

Coal gangue (CG) has become a critical environmental challenge in China, with nearly one billion tons produced annually. To address this challenge while simultaneously supplementing soil resources during mine ecological restoration, a novel process is proposed to convert CG into CG-based artificial soil (CGAS) using a microbial treatment method. This study examined the effects of local microbial agents (LMAs), commercial microbial agents (CMAs), and fly ash (FA) on key soil properties of CGAS, such as organic matter (OM) content, humic acid (HA) content, and water-holding capacity. Additionally, the mechanisms underlying aggregate formation in CGAS were investigated. The results showed that the synergistic effect of LMAs and FA significantly enhanced the essential quality properties of CGAS. In particular, the HA content increased by 2.06 times compared with untreated CG, the proportion of water-stable macroaggregates increased to 11.46%, and the bulk density decreased by 39.71%, achieving an optimal level of 1.30 g/cm³. Analysis of phase compositions, surface functional group characterization, and microstructural examination indicated that organic binders such as HA, inorganic binders such as calcium carbonate and gypsum, and the bonding effect of spherical particles of FA played significant roles in forming a stable and healthy soil structure in CGAS. Full article

It is known that there are significant deposits of lignite (brown coal) in Ukraine, particularly in categories A + B + C1. At the same time, certain technical and legal obstacles limit its use as an energy carrier. Therefore, new methods of using lignite and processing its products are necessary. The latter includes humic acids. It was suggested that these acids could be used to stop road bitumens from breaking down. This is because they are antioxidants that contain functional phenolic and carboxyl groups. In particular, this article analyses the nature of the influence of humic acids on the physical and mechanical properties of road petroleum bitumen and its resistance to technological aging. It was found that at a modification temperature of 120 °C (duration-60 min., consumption of humic acids-2.0 wt.%), this additive has a slight negative effect (changes are within permissible limits) on the plastic properties of bitumen and slightly improves its elasticity. The main reason for adding humic acids to road bitumen under the specified conditions is to improve its resistance to technological aging compared to the original binder. Full article

Conventional potassium chloride granules have inefficient applications in agricultural production due to particle irregularity and low fluidity. The application of controlled-release potassium chloride could increase the potassium-use efficiency and alleviate the shortage of potassium ore resources. In this study, a well-rounded potassium chloride fertilizer core was prepared, using the graft modification of polyurea to enhance the coating rate and release performance. The adhesive and tensile characteristics of the modified polyurea binder, as well as the granule properties of modified polyurea binder potassium chloride, were studied to determine the ideal lignin-grafted ratio. The effect of the modified polyurea binder with potassium chloride on the properties of coated fertilizer was investigated. The findings, shown by radar maps of the binder’s properties, demonstrated that the ideal mass ratio of the modified lignin polyurea binder to urea is 1:2. The Fourier-transform infrared spectroscopy results demonstrated that the amino functional groups of lignin were enhanced, improving the product’s interfacial compatibility with the polyurea matrix. Compared to humic acid (HA; 12%) and bentonite (Ben; 30%) treatments, the granule intensity of the 9.9%—1:2 treatment considerably increased by 139.10% and 38.86%, respectively, while the static angle of the granules reduced by 16.67% and 3.81%. The 28-day cumulative release rate of the modified polyurea (9.9%—2:1) with a 5% coating thickness was the lowest (28%), 42% lower than that of the lowest conventional treatment. In summary, the creation of a bio-lignin polyurea binder under the optimum conditions reduced the need for petrochemical-based materials, allowed the preparation of fertilizer with granules of increased fluidity, and enabled the successful coating of a high-salt potassium fertilizer, offering a novel technique for the high-value application of potash fertilizer coating. Full article

Due to the detrimental impact of steel industry emissions on the environment, countries worldwide prioritize green development. Replacing sintered iron ore with pellets holds promise for emission reduction and environmental protection. As high-grade iron ore resources decline, research on limonite pellet technology becomes crucial. However, pellets undergo rigorous mechanical actions during production and use. This study prepared a series of limonite pellet samples with varying ratios and measured their compressive strength. The influence of humic acid on the compressive strength of green and indurated pellets was explored. The results indicate that humic acid enhances the strength of green pellets but reduces that of indurated limonite pellets, which exhibit lower compressive strength compared to bentonite-based pellets. Furthermore, artificial neural networks (ANN) predicted the compressive strength of humic acid and bentonite-based pellets, establishing the relationship between input variables (binder content, pellet diameter, and weight) and output response (compressive strength). Integrating pellet technology and machine learning drives limonite pellet advancement, contributing to emission reduction and environmental preservation. Full article

In order to pursue the goal of low-carbon ironmaking, a new type of humic acid (HA)-based binder was applied to the preparation of oxidized pellets from vanadium-bearing titanomagnetite (VTM) in this work. Effects of the HA binder (or with limestone) on the balling, preheating, and roasting behaviors of VTM were comparatively studied with bentonite. The embedded features of each mineral phase in sintered pellets, especially the crystallization and growth state of hematite grains, were deeply investigated by XRD, optical microscopy, and SEM–EDS measures. The binder dosage can be cut down by 50% when HA was used instead of bentonite. Fine hematite grains in HA pellets evolved into plump interlocking grains with ~5% of limestone addition. Pseudobrookite and magnesioferrite spinel phase formed at the optimal sintering temperature of 1250 °C, which could hinder the crystallization of hematite and affect the strength of final pellets. Full article

A novel composite binder (humic acid modified bentonite, HAMB) and two other binders (bentonite and Modified humic acid, MHA) were used to explore the effects of binders on the properties of magnetite green pellets in this study. The results of green pellet properties and drying tests show that the low doses of a humic substance-based binder can achieve the same effect as high doses of bentonite binder. A humic substance-based binder could be a promising organic binder to replace bentonite. Meanwhile, the influence mechanism of adding different binders on the strength of green pellet was discussed, and the relationship between moisture content in the pellet and the compression strength of three binders was determined. A TG-DSC analysis found that the novel composite binder (HAMB) was not a simple mix of humic acid and bentonite, in which a humic substance could change the structure of bentonite and reduce the thermal stability of bentonite, causing the HAMB composite binder to have a high decomposition temperature. Full article

The oxidation roasting of vanadium–titanium magnetite (VTM) pellets with a new composite binder was investigated using a pilot-scale straight-grate. The evolution of the chemical and phase composition, the compressive strength, and the metallurgical properties of the fired VTM pellets were investigated. Under a preheating temperature of 950 ${}^{\circ }$C, a preheating time of 18 min, a firing temperature of 1300 ${}^{\circ }$C, and a firing time of 10 min, the compressive strength of the fired pellets was as high as 2344 N per pellet. The fired pellets mainly consisted of hematite, pseudobrookite, spinel and olivine. The total iron content of the fired pellets was 0.97% higher using 0.75 wt% humic acid (HA) binder instead of 1.5 wt% bentonite binder. These properties are beneficial for the production efficiency and energy efficiency of their subsequent use in blast furnaces. Moreover, both the softening interval and the softening melting interval of the HA binder pellets were narrower than those of the bentonite binder pellets, conducive to the smooth and successful smelting of the VTM pellets in a blast furnace. Full article

The aim of this study was to characterize 27 feed additives marketed as mycotoxin binders and to screen them for their in vitro zearalenone (ZEN) adsorption. Firstly, 27 mycotoxin binders, commercially available in Belgium and The Netherlands, were selected and characterized. Characterization was comprised of X-ray diffraction (XRD) profiling of the mineral content and d-spacing, determination of the cation exchange capacity (CEC) and the exchangeable base cations, acidity, mineral fraction, relative humidity (RH) and swelling volume. Secondly, an in vitro screening experiment was performed to evaluate the adsorption of a single concentration of ZEN in a ZEN:binder ratio of 1:20,000. The free concentration of ZEN was measured after 4 h of incubation with each of the 27 mycotoxin binders at a pH of 2.5, 6.5 and 8.0. A significant correlation between the free concentration of ZEN and both the d-spacing and mineral fraction of the mycotoxin binders was seen at the three pH levels. A low free concentration of ZEN was demonstrated using binders containing mixed-layered smectites and binders containing humic acids. Full article