By-product Gypsum Research Articles

Innovative Application and Research of Industrial Solid Waste in Mining Filling Materials in China

The swift advancement of China’s mining sector has led to the generation of substantial amounts of industrial solid waste, which poses significant risks to the ecological environment. This study aims to investigate effective methods for utilizing industrial solid waste in the production of mine filling materials, thereby facilitating green mine construction and the efficient use of resources. The study employs the PRISMA methodology to conduct a systematic review of the pertinent literature, analyzing the current status, challenges, and developmental trends associated with the use of coal-based solid waste, smelting waste, industrial by-product gypsum, and tailings in filling materials. The findings indicate that, while the use of individual coal-based solid waste in filling materials shows promise, there is a need to optimize the ratios and activation technologies. Furthermore, the synergistic application of multi-source coal-based solid waste can enhance the overall utilization rate; however, further investigation into the reaction mechanisms and ratio optimization is required. Smelting slag can serve as a cementing agent or aggregate post-treatment, yet further research is necessary to improve its strength and durability. Industrial by-product gypsum can function as an auxiliary cementing material or activator, although its large-scale application faces significant challenges. Tailings present advantages as aggregates, but concerns regarding their long-term stability and environmental impacts must be addressed. Future research should prioritize the synergistic utilization of multi-source solid waste, performance customization, low-carbon activation technologies, and enhancements in environmental safety. Additionally, the establishment of a comprehensive lifecycle evaluation and standardization system is essential to transition the application of industrial solid-waste-based filling materials from empirical ratios to mechanism-driven approaches, ultimately achieving the dual objectives of green mining and the resource utilization of solid waste in mining operations.

Influence of By-Product Gypsum and Concrete Waste on The Structural and Mineralogical Properties of Peat Soil

Abstract The high organic content of peat soil significantly affects its structural characteristics, leading to low shear strength and high compressibility, causing serious building problems, such as settlement or structural instability. Using unsustainable, costly materials within conventional methods for stabilisation has propelled interest in sustainable alternatives. Accordingly, this study aims to investigate the feasibility of using sustainable stabilizers, by-product gypsum and concrete waste, to enhance the structural and mineralogical properties of peat soil. Analytical tests, including SEM, EDX, XRD, and FTIR tests were conducted to evaluate the effectiveness of these stabilizing materials. The results demonstrated that the stabilized peat soil exhibited a denser, more cohesive soil matrix with improved particle bonding and reduced pore gaps. Crystalline phases of quartz and kaolinite were also observed, contributing to increased strength and reduced compressibility. Additionally, a notable reduction in organic content and an increase in stabilizing components like sulphur and calcium were identified. These findings highlight the potential of this approach as a cost-effective and environmentally sustainable solution for addressing the challenges associated with peatlands in construction practices.

Influence of calcination temperature of industrial by-product gypsum on sulphoaluminate cement-based grouting material

Influence of calcination temperature of industrial by-product gypsum on sulphoaluminate cement-based grouting material

Stabilization of Copper, Lead, and Zinc in Copper Smelting Slag Tailings by Sulfate-reducing Bacteria Using Typical Industrial By-product Gypsum as a Sulfur Source

Stabilization of Copper, Lead, and Zinc in Copper Smelting Slag Tailings by Sulfate-reducing Bacteria Using Typical Industrial By-product Gypsum as a Sulfur Source

Utilization of Industrial By-product Gypsum Resource during Manufacture of Gypsum Mold Box Molding System

Utilization of Industrial By-product Gypsum Resource during Manufacture of Gypsum Mold Box Molding System

Advances in the Application and Mechanism of Admixtures and Industrial By-Products in Cement-Based Self-Leveling Mortar: A Comprehensive Review.

Cement-based self-leveling mortar (CSL) is a special building material that utilizes cement as the main cementitious component, combined with a variety of admixtures. Its self-leveling characteristics enable it to effectively level and fill uneven surfaces. Additionally, the innovative green CSL developed from industrial by-products can further enhance both environmental and economic benefits. This paper systematically reviews the use of admixtures and industrial by-products in the production of CSL. The main findings include the following: (i) compared to the international ISO standard, China's standard JC/T 985 provides more detailed testing parameters regarding fluidity, mechanical properties, and shrinkage; (ii) the effect of additives on CSL is affected by its molecular weight and structure, and high molecular weight improving the workability of the additives; (iii) industrial by-products have been effectively incorporated into CSL, leading to a reduction in reduced greenhouse gas emissions and a decreased environmental impact; (iv) macro and microanalysis results of different green CSLs show that industrial by-product gypsum has the greatest potential for application in CSL. Based on these findings, this paper offers valuable reference data for the use of admixtures and industrial by-products in CSL. Furthermore, it contributes innovatively to the sustainable development of infrastructure construction.

Characterization and identification of elemental sulphur, iron pyrite, mineral gypsum, phospho gypsum and marine gypsum using SEM-EDAX

India has 6.73 million ha of salt-affected soils, of which 3.77 million ha is sodic soil. Sodicity is a serious issue in agriculture, and it prevents to meet the properties of fertile soil. Sodicity alters its physical and chemical properties, including soil structure and hydraulic conductivity. High exchangeable sodium and pH decrease soil permeability, available water capacity and infiltration rates through swelling and dispersion of clays as well as slaking of soil aggregates. Gypsum is one of the sources used for sodic soil reclamation, and the cheaper and alternative source is marine gypsum which is recovered from salt pans during production of common salt in coastal region, particularly in Gujarat and Tamil Nadu. The recovery of by-product gypsum and marine gypsum together is substantial and is comparable with the production of mineral gypsum.The amendments generally used for sodic soil reclamation should be a source of sulphates such as elemental sulphur, iron pyrite, mineral gypsum, phospho gypsum and marine gypsum. Characterization of sources by SEM–EDAX is rapid and elementary. The elemental composition revealed by the spectra of the bentonite sulphur for weight percentage and atomic percentage of sulphur is quantified as 34.04% and 18.59%, respectively, in the ZAF matrix. In iron pyrite spectra the weight percentage and atomic percentage of sulphur are 4.89% and 2.31%,respectively, in the ZAF matrix, while in mineral gypsum, the calcium weight percentage is 10.14% and atomic percentage is 04.04% while sulphur weight percentage is 6.52%, atomic percentage is 3.50%. The calcium composition in phosphogypsum is weight percentage is 14.69%; Atomic percentage is 34%, and the sulphur composition in phosphogypsum is weight percentage 10.40%, atomic percentage 5.60%, whereas in marine gypsum the calcium (weight percentage 09.10%, atomic percentage 03.58%) and sulphur (weight percentage 06.28%, atomic percentage 03.09%) proportions dominate as like two other above-mentioned gypsums, the element which makes difference in the marine gypsum from others is sodium (Weight percentage 00.18%, atomic percentage 00.12%). This helps to confirm that marine gypsum is an economic and alternate source available for sodic soil reclamation.

A novel neutralization process for improving dehydration performance of industrial by-product gypsum

A novel neutralization process for improving dehydration performance of industrial by-product gypsum

Effect of Industrial Byproduct Gypsum on the Mechanical Properties and Stabilization of Hazardous Elements of Cementitious Materials: A Review.

Industrial byproduct gypsum (BPG) is a secondary product that is mainly composed of calcium sulfate discharged during industrial production. BPG primarily consists of desulfurized gypsum, phosphogypsum, and titanium gypsum, which account for 88% of the total BPG in China. The large-scale utilization of these three types of solid waste is crucial for the safe disposal of BPG. BPG contains various impurities and harmful elements, limiting its applications. The continuous accumulation of BPG poses a serious threat to the safety of the environment. Based on a literature review (2021-2023), it was found that 52% of BPG is used in the preparation of cementitious materials, and the addition of BPG results in an average improvement of 7-30% in the mechanical properties of cementitious materials. Moreover, BPG has a positive impact on the immobilization of hazardous elements in raw materials. Therefore, the utilization of BPG in cementitious materials is beneficial for its large-scale disposal. This study primarily reviews the effects and mechanisms of BPG on the mechanical properties of cementitious materials and the solidification of hazardous elements. Most importantly, the review reveals that BPG positively influences the hydration activity of silica-alumina-based solid waste (such as steel slag and blast furnace slag) and alkaline solid waste (such as carbide slag and red mud). This improves the proportion of solid waste in cement and reduces production costs and carbon emissions. Finally, this article summarizes and proposes the application of BPG in cementitious materials. The application of BPG + silica-alumina solid waste + alkaline solid-waste-based cementitious materials is expected to realize a new type of green ecological chain for the joint utilization of multiple industrial solid wastes and to promote the low-carbon sustainable development of industrial clusters.

Recycling industrial byproduct gypsum for use as plastering materials by the tandem pyro-hydro process: impurities removal, whiteness improvement, and regularity of phase evolution

Recycling industrial byproduct gypsum for use as plastering materials by the tandem pyro-hydro process: impurities removal, whiteness improvement, and regularity of phase evolution

Research on the Performance and Application of a Low-Carbon Waste-Recycling Cement

This paper mainly introduces the history of the formation and development of an ultra-high performance low-carbon waste-utilizing cement (fast-setting and fast-hardening high-belite sulphoaluminate cement). This cement not only uses a large amount of solid waste (fly ash, blast furnace slag, industrial waste gypsum, alkali slag, etc.) as raw materials, and the waste utilization can reach 40%~95%, but also has a calcination temperature of 150~200℃ and 50 ℃ lower than that of traditional ordinary Portland cement and sulphoaluminate cement, and the carbon emission is equivalent to 30%~60% and 50%~80%. Through the elaboration of its main mineral composition, chemical composition, physical properties and action mechanism, the reasons for its excellent properties such as good whiteness, fast setting and hardening, high late strength, and small dimensional deformation are analyzed. And the application research is focused on the fields of inorganic flooring, airports, road quick repair, prefabricated walls, ultra-light and efficient A-level fire insulation, cement crafts, inorganic artificial stone, and UHPC ultra-high performance concrete. At present, there are many types of low-carbon cement in the world, including Porsol cement, Alinit cement, Celitement cement, Japanese eco-cement, multi-component high-mixture cement, high-belite cement, Anther cement, BCT cement, etc., but most of the products have a slow coagulation and hardening speed, and cannot meet the needs of rapid demolding, turnover, and traffic opening for mortar, concrete, cement products or pavements; at the same time, the production process is complicated and cumbersome, the later strength is low, the deformation is large, and the durability is poor. Therefore, in the actual promotion process in the engineering field, there are great difficulties and many constraints. Among them, Aether cement and BCT cement belong to the belite-sulfoaluminate cement system. Aether cement has 6h early strength performance. Compared with Portland cement (burning temperature1400~1500℃), it can significantly reduce production energy consumption, reduce CO2 emissions by 25%~30% per ton of cement, and the 28-day compressive strength reaches the strength level of standard cement (CEMⅠ52.5R); the size shrinkage of this concrete is less than 50% of that of OPC concrete, but its raw materials still use limestone, bauxite, gypsum, iron raw materials and marl raw materials, without effective utilization of bulk industrial waste, and CO2 emissions are far from meeting the low-carbon environmental protection requirements. BCT cement can be produced at a lower temperature (1250~1300℃), and its raw materials use industrial waste residues such as limestone, marl, fly ash and industrial by-product gypsum. CO2 emissions are 30% lower than traditional OPC cement clinker, but there is no early hourly strength, and the strength after 1~2 days is higher than that of ordinary Portland cement. This is far from the goal of using bulk industrial waste as raw materials to produce green, low-carbon, energy-saving and high-performance cement materials, which is currently widely used at home and abroad. At the same time, the above-mentioned low-carbon cement cannot effectively and reasonably control key indicators such as cement whiteness value, early strength before 4 hours, and dimensional change rate, and cannot meet the requirements of high-performance cement. At the same time, the production process is not mature and stable enough, and there is still a long way to go to meet the comprehensive popularization of production industrialization and promotion scale.

Application of the Industrial Byproduct Gypsum in Building Materials: A Review.

The industrial byproduct gypsum is a general term for byproducts discharged from industrial production with calcium sulfate as the main ingredient. Due to the high number of impurities and production volume, the industrial byproduct gypsum is underutilized, leading to serious environmental problems. At present, only desulfurization gypsum and phosphogypsum have been partially utilized in cementitious materials, cement retarders, etc., while the prospects for the utilization of other byproduct gypsums remain worrying. This paper mainly focuses on the sources and physicochemical properties of various types of gypsum byproducts and summarizes the application scenarios of various gypsums in construction materials. Finally, some suggestions are proposed to solve the problem of the industrial byproduct gypsum. This review is informative for solving the environmental problems caused by gypsum accumulation.

Evaluation of Technological Properties of Mortars with the Addition of Plaster Byproduct

The incorporation of waste into construction materials is a potential topic for study and is seen as a solution for many industries that face the following impasse: the risk to the environment due to the accumulation of waste in yards. In view of this, during the production of lactic acid, which is widely used in industries, gypsum is produced as a byproduct, yielding one ton for each ton of lactic acid. Aiming at a functional destination for this byproduct, this study proposes its addition in mortars for covering walls and ceilings. The research proposal was a mortar in a 1:6 ratio (cement:sand) with the addition of 0, 3, 6 and 10% of industrial plaster byproduct. The cement used to prepare the mortar was CPII-E32. To characterize the raw materials, scanning electron microscopy, X-ray fluorescence and X-ray diffraction analysis were carried out. To evaluate the properties in the fresh state, a consistency index and mass density and entrained air tests were carried out. In the hardened state, mass density, axial compression strength, flexural tensile strength and water absorption via capillarity were evaluated after 28 days of age. Microstructural characterization techniques were also carried out on the reference mixtures and with 3% addition of the byproduct gypsum, such as scanning electron microscopy and X-ray diffraction. The results showed that the byproduct is hemihydrate and its addition improved the workability of the mortar. Mortars with the addition of byproduct gypsum showed a reduction in mechanical resistance. The most satisfactory results were for the mixes with a 3% addition, indicating greater resistance to axial compression and flexural traction, with 3.90 MPa and 1.14 MPa, respectively.

Insight into the high-temperature reaction characteristics of CaS with CO2: Experimental study and theoretical calculation

Insight into the high-temperature reaction characteristics of CaS with CO2: Experimental study and theoretical calculation

Reuse of by-product gypsum with solid wastes-derived sulfoaluminate cement modification for the preparation of self-leveling mortar and influence mechanism of H3PO4

Reuse of by-product gypsum with solid wastes-derived sulfoaluminate cement modification for the preparation of self-leveling mortar and influence mechanism of H3PO4

Construction of Testing Standards System for Comprehensive Utilization of Bulk Industrial Solid Waste

According to the general steps of comprehensive utilization of each type of bulk industrial solid waste, including fly ash, coal gangue, tailings, smelting slag, industrial by-product gypsum, and red mud, we construct the testing standards system for comprehensive utilization of bulk industrial solid waste in China. The standards system, according to the lifecycle stage of "raw materials - pre-treatment - processing - forming products - using products", can be divided into 5 standard subsystems, namely a subsystem of physical property testing standards for raw materials, a subsystem of chemical property testing standards, a subsystem of process testing standards, a subsystem of the product quality performance testing standards and a subsystem of the environmental impact testing standards. The standards system provide top-level guidance for the implementation and development of comprehensive utilization testing methods for bulk industrial solid waste.

Insight into the reaction characteristics of H2-reduction decomposition of gypsum: Experimental and isothermal kinetic analysis

Insight into the reaction characteristics of H2-reduction decomposition of gypsum: Experimental and isothermal kinetic analysis

Comparison of the effectiveness of mined and by-product South African gypsums and other calcium sources for soil sodicity remediation

Studies evaluating the effectiveness of South African gypsum sources are scarce or outdated because of newly introduced products, such as granulated and liquid gypsums. The efficacy of calcium (Ca) nitrate and micro-fine (MF) calcitic limes in comparison to gypsums has also never been evaluated. The aim of this study was to compare the effectiveness of mined and by-product gypsums and other Ca sources in terms of soil sodicity remediation and saturated hydraulic conductivity (Ksat) improvement. In a controlled laboratory study, 12 mined and by-product gypsums sources, MF calcitic limes and calcium nitrate were surface-applied to a sodic, sandy loam soil to achieve an exchangeable sodium percentage (ESP) of 5%. The soils received 300 mm simulated rainfall, and then soil chemical properties and Ksat were determined. Finer by-product gypsum sources (particularly liquid and flue gas desulphurisation (FGD) gypsums) exhibited faster dissolution rates and superior performance in lowering soil ESP to 4.2–4.7% and pH by 0.5–0.7 units compared to Class A mined gypsums (ESP 9.0–11.1% and 0.2 pH units). Only the liquid, phospho-, FGD gypsums and calcium nitrate significantly increased soil hydraulic conductivity (123–130%) compared to the control. The MF calcitic limes had no effect on the sodic soil properties.

Facile preparation of α-calcium sulfate hemihydrate whisker from by-product gypsum in chloride-free salt solution system

Facile preparation of α-calcium sulfate hemihydrate whisker from by-product gypsum in chloride-free salt solution system

Progress in the Preparation of Calcium Carbonate by Indirect Mineralization of Industrial By-Product Gypsum

To avoid the long-term pollution of land and water by industrial gypsum by-products, the exploitation of this resource has become a priority. The indirect synthesis of calcium carbonate from the industrial by-product gypsum has received substantial attention as a viable method for resource utilization. Currently, the primary problems in the indirect manufacture of calcium carbonate from the industrial by-product gypsum are additive recycling and process simplification. This paper describes the present state of development and compares various indirect mineralization systems. The factors affecting leaching and mineralization in the indirect mineralization of CO2 from by-product gypsum and the management of CaCO3 crystallinity are discussed, and the current additive regeneration cycle is summarized. The applications of other technologies in the indirect mineralization of by-product gypsum are also summarized, as are the obstacles, and required future work. This review provides guidelines for the laboratory indirect mineralization of by-product gypsum as well as practical applications.