Tailing Sand Research Articles

Expansive soil modified by iron tailing sand and calcium carbide slag as subgrade material

Expansive soil modified by iron tailing sand and calcium carbide slag as subgrade material

Study on influencing factors of shear characteristics of rock-fill concrete layer of iron tailings as fine aggregate

With global energy conservation and emission reduction, recent research have begun to explore the possibility of iron tailings application in concrete. The layer condition of rockfill concrete is directly related to the shear strength of the layers, and affects engineering stability. In this research, the shear performance of iron tailings as fine aggregate rockfill concrete with different layer characteristics was investigated. In this paper the particle size distribution, fineness modulus, stone powder content, density, chemical composition, mineral composition and other basic properties of iron tailing sand were measured. Experimental data were compared with mechanical sand and combined with microscopic morphology observation to verify the feasibility of iron tailing sand to replace mechanical sand in the preparation of rockfill concrete. 12 groups of rockfill concrete with iron tailings with different layer characteristics and 1 group of rockfill concrete with iron tailings without layer were designed. The influence of different rockfill exposure height and area, degree of roughen and content of stone powder, afterward, all the rockfill concrete samples were subjected to four grades of normal stress loading shear tests, control group without layer was comparedwithdifferent layers. The observed microstructure morphology and physicochemicalproperties show that iron tailings as fine aggregate can be used to replace mechanical sand in the preparation of rockfill concrete, however, the content of stone powder and mud in iron tailings should be controlled. It is concluded that the shear failure of layered rockfill concrete samples is in two forms, failure along one side of the specimen and failure along the shear layer. Rockfill exposure height and area, degree of roughen and content of stone powder, all have a certain degree of impact on shear characteristics, rockfill exposed stone area has the greatest effect, and the shear strength increases by 4.92%∼38.24%. The increase of shear strength at the interface of rockfill concrete with multi-aggregate layer is less than the aggregate shear strength under the influence of a “stone group effect”. The stone powder content of rockfill concrete increases, the layer shear strength also decreases. The overall results indicate that useful references for the design of sheering properties of layers of rockfill concrete and construction of rockfill concrete layer in the future.

Biocementation of Pyrite Tailings Using Microbially Induced Calcite Carbonate Precipitation.

Tailing sand contains a large number of heavy metals and sulfides that are prone to forming acid mine drainage (AMD), which pollutes the surrounding surface environment and groundwater resources and damages the ecological environment. Microbially induced calcium carbonate precipitation (MICP) technology can biocement heavy metals and sulfides in tailing sand and prevent pollution via source control. In this study, through an unconfined compressive strength test, permeability test, and toxic leaching test (TCLP), the curing effect of MICP was investigated in the laboratory and the effect of grouting rounds on curing was also analyzed. In addition, the curing mechanism of MICP was studied by means of Fourier transform infrared spectroscopy (FTIR), thermogravimetric analysis (TGA), X-ray diffraction spectroscopy (XRD), and scanning electron microscopy (SEM). The experimental results showed that MICP could induce calcium carbonate precipitation through relatively complex biochemical and physicochemical reactions to achieve the immobilization of heavy metals and sulfides and significantly reduce the impact of tailing sand on the surrounding environment.

Research on the Regional Environmental Impact and Risk Assessment Affected by Mineral Resource Development: A Case Study of the Taojia River Watershed in Hunan

The mining and production of mineral resources can directly lead to soil and water pollution, posing a serious threat to human health. In this study, the Taojia River basin, a tributary of the Xiangjiang River, was selected as the study area. Based on the concentrations of heavy metals (As, Cd, Pb, and Zn) in 653 soil/substrate samples collected from 342 points in the study area in 2013 and 2021, the changes in soil heavy metal concentrations in the region were systematically analyzed to assess their environmental risks and impacts on regional environmental quality. The results showed that from 2013 to 2021, the As, Pb, and Zn pollution in regional soil, tailing sand, and surface water was reduced, while the Cd pollution increased. The average soil As, Pb, and Zn concentrations decreased from 3,750, 2,340, and 1,180 mg/kg to 457, 373, and 387mg/kg, respectively, while the Cd concentration increased from 0.11to 1.91 mg/kg; additionally, the overall distribution trend of heavy metal concentrations was high in the south, low in the north, and gradually decreased from upstream to downstream. The single evaluation index of heavy metal pollution risk showed that the percentages of medium to heavy pollution points in the soil As, Pb, and Zn were 84, 57, and 28%, respectively, in 2013, and this index decreased to 38, 37, and 25%, respectively, in 2021. The regional environmental quality was closely related to the intensity of mineral resource development. From 2000 to 2010, frequent mining development activities led to an increase in the area of construction land and a continuous decrease in the area of arable land, grassland, and vegetation cover in the region. During 2010–2020, the area of construction land decreased, and the vegetation coverage increased. The comprehensive evaluation index showed that the overall soil pollution risk in the watershed decreased, and the proportion of heavily polluted points decreased from 80 to 65%. It was shown by principal component analysis and factor analysis that mining development activities were the largest source of heavy metal pollution, in addition to mixed sources of tailings, solid waste, agriculture, and traffic emission sources. The results provide a scientific basis for the management and risk control of heavy metal pollution in the Taojia River basin.

CaCO3-assisted mechanochemical synthesis of low-cost and high-chroma cobalt blue composite pigments using kaolin tailing sand for ceramic coloring

To reduce the wastes discharging and production cost for preparation of cobalt blue pigments via common liquid-phase methods, the low-cost and high-chroma cobalt blue composite pigments are fabricated via CaCO3-assisted mechanochemical route followed by an annealing process based on the discarded kaolin tailing sand (KTS) from the mineral processing. The preparation conditions, formation and coloring mechanisms of composite pigments are studied systematically. The optimal color performance (L* = 40.54, a* = 4.12, b* = −55.22) is obtained after optimizing the preparation conditions. The results indicate that CaCO3 acts as a mild precipitant with the assistance of mechanochemical effects to form the precursor. Furthermore, incorporation of KTS improves the color lightness and blueness of cobalt blue pigments due to the reflection of KTS toward light and well dispersion of CoAl2O4 on KTS surface. Compared with the commercial cobalt blue pigments, the oil absorption and hiding power of composite pigments are high while the relative tinting strength slightly reduces owing to the differences in their size and CoAl2O4 content, but the composite pigments may be more popular due to the low production cost and excellent color performance. Moreover, the as-prepared composite pigments present excellent acid-resistance and coloring performance as a ceramic pigment.

Study on Compressive Properties and Dynamic Characteristics of Polypropylene-Fiber-and-Cement-Modified Iron-Ore Tailing under Traffic Load.

Using polypropylene (PP) fiber and cement to modify iron-ore tailing and applying it to road engineering is an effective way to reuse iron-ore tailing. The compressive properties and deformation characteristics of PP-fiber-and-cement-modified iron-ore tailing (FCIT) under traffic load were studied by the unconfined-compressive-strength (UCS) test and the dynamical-triaxial (DT) test. The test results indicated that the UCS and residual strength both increased with increasing PP-fiber content, and tensile and toughness properties were positively correlated with PP-fiber content. Moreover, the dynamic elastic modulus and damping of FCIT both showed a negative linear relationship with cycle time. It can be found from the test results that 0.75% was the best PP-fiber content to modify iron tailing sand in this work. Lastly, a prediction model was developed to describe the relationship between the cumulative plastic strain, PP-fiber content and cycle time, which can effectively capture the evolution law of the cumulative plastic strain with cycle time of FCITs at different PP-fiber contents.

Bio-Matrix Pot Addition Enhanced the Vegetation Process of Iron Tailings by Pennisetum giganteum.

The barrenness of large mine tailing sand reservoirs increases the risks for landslides and erosion that may be accompanied with transfer of contaminants into the surrounding environment. The tailing sand is poor in nutrients, which effectively complicates the vegetation process. We investigated direct planting of Pennisetum giganteum into tailing sand using two pit planting methods: the plants were transplanted either directly into pits filled with soil or into soil-filled bio-matrix pots made of organic material. After growing P. giganteum in iron tailing sand for 360 days, the dry weight of the plants grown in the bio-matrix pot (T2) was approximately twofold higher than that of the plants grown in soil placed directly into the sand (T1). At 360 days, the organic matter (OM) content in the soil below the pit was the lowest in the not-planted treatment (T0) and the highest in T2, the available N (AN) contents were higher in T1 and T2 than in T0, and the available P and K contents were the highest in T2. At 360 days, the Shannon diversity of the soil microbial communities was higher in T1 and T2 than in T0, and the community compositions were clearly separated from each other. The profiles of predicted C cycle catabolism functions and N fixation-related functions in T1 and T2 at 360 days were different from those in the other communities. The results showed that P. giganteum grew well in the iron tailing sand, especially in the bio-matrix pot treatment, and the increased nutrient contents and changes in microbial communities indicated that using the bio-matrix pot in planting had potential to improve the vegetation process in iron tailing sands effectively.

Synergistic remediation of copper mine tailing sand by microalgae and fungi

Biological soil crusts (BSCs) could strengthen soil particles, increase soil nutrients, and reduce soil erosion. However, available information on stabilizing mine tailing sand by induced BSCs is lacking. In this study, a native microalgae (i.e., Coelastrella sp.) and two fungi (i.e., Aspergillus sp. and Penicillium sp.) isolated from Cu mine tailing sand were inoculated onto the tailing sand in different manners. After being inoculated for 90 days, microorganisms could effectively colonize and form BSCs on the surface of the tailing sand, as proven by scanning electron microscopy images and growth parameters, and the dual inoculation of microalgae and fungi showed synergistic effects on the improved soil properties. Compared with the control treatment, the microorganism co-inoculation group had increased organic carbon, cation exchange capacity, soil moisture, sucrase activity, and microbial biomass carbon by 55.41%, 27.18%, 6.29%, 471%, and 216%, respectively; decreased pH from 9.09 to 8.95; and decreased bioavailable Cu content and bulk density by 15.43% and 6.30%, respectively. This finding indicated that the formation of BSCs could effectively improve the soil properties of mine tailing sand. The composition of dissolved organic matters analyzed by excitation–emission matrix showed that the increase in carbon content in tailing sand was predominantly caused by microalgae and fungi. These results indicated that the use of native microorganisms to construct biological crusts could effectively improve the properties of tailing sand and increase the nutrient content, and it could be used as a new method for tailing restoration.

Process enhancement of vibrating classifier for tailings classification-dewatering and industrial application

To reduce environmental pollution and wastage of resources and to promote the large-scale utilization of tailings, classification-dewatering is a key technical challenge. The vibrating classifier efficiently separates minerals according to particle size, while the vibrating energy drives water out. However, the screen apertures of the vibrating classifier can be blocked easily, resulting in a poor classification-dewatering effect. In this study, an elastic screen surface for classification-dewatering is proposed to replace the rigid screen surface of a traditional vibrating classifier, eliminating the problems of easy plugging and low efficiency. The surface kinematics of the elastic screen under simple harmonic excitation is studied. The output energy of the screen surface increased by 10% compared with the input energy of the excitation source. In addition, the random elastic deformation of the screen's apertures contributed to the rupturing of water film in apertures. The effect of exciting parameters and concentrations of tailings on the classification-dewatering is also investigated. The optimum values for excitation force, working frequency, and the concentration of tailings are 9.66 kN, 15.62 Hz, and 35%, respectively. Moreover, the classification and dewatering efficiencies are 80% and 53%, respectively. Industrial production shows that coarse tailing sand exhibits a moisture content of 18%, while the fine particles are used for paste filling. These results provide support to the comprehensive utilization of tailings and promote green and safe production in mines

Research on the high-temperature resistance of recycled aggregate concrete with iron tailing sand

Recycled aggregate concrete (referred to as RAC) prepared from construction waste is of great importance to the sustainable development of the construction industry. In this study, iron tailing sand is used as fine aggregate, and the treated waste concrete is used as coarse aggregate to prepare RAC with irontailing sand. The compressive strength, flexural strength, and splitting tensile strength are tested. The optimal replacement rate of recycled aggregate is determined by comparing the above mechanical indicators. Comparing the high-temperature resistance of the natural aggregate concrete (referred to as NAC) and the RAC prepared under the optimal replacement rate of recycled aggregate is crucial. Results show that when iron tailing sand is used as fine aggregate, the concretes prepared with different replacement rates of recycled aggregate all show good mechanical properties. The concretes show the best comprehensive mechanical properties when the replacement rate of recycled aggregate is 50%. With the increase in temperature, the residual compressive strength and residual flexural strength show a downward trend as a whole. However, no obvious loss is found in the residual strength of concrete at approximately 200 °C, and a slight increase is observed at approximately 300 °C. Compared with NAC, RAC with iron tailing sand shows better high-temperature resistance after a fire. The recycling of iron tailing sand and recycled aggregate can formulate concrete with good comprehensive properties.

Study and Application of Full Tailing Deep Concentration and Rapid Dewatering Technology

The problem of unstable full tailing sand concentration and dewatering in some mine filling systems has led to substandard bottom flow concentration of tailing sand concentration equipment, wide fluctuation ranges of filling concentration, substandard return water concentration at filling stations, and high flocculant addition cost. Through flocculation and sedimentation tests, the effect of the flocculant and sedimentation law and the effect of slurry concentration on sedimentation rate were studied, and the field application of the flocculant addition point model was verified. The results showed that (1) when the dose of the flocculant was added, the F1‐type polyacrylamide as the flocculant made the best settling effect of the whole tailing sand in the test, as judged by comparing the falling rate of the clarified layer and the clarification degree of the supernatant. (2) With the increasing flocculant concentration, the settling speed of tailing sand gradually becomes slower; the range of the best settling concentration was 8%–18% of tailing sand concentration; and the concentration of tailing sand corresponding to the maximum solid flux was 10%–14%. (3) Relying on the site conditions of a domestic copper mine, the feed concentration was diluted from 20%–25% to 10%–12%, and the overflow water clarification test was less than 300 ppm, which verified the flocculant test and the correctness of the flocculant addition point model. The type and dosage of the flocculant as well as the feed concentration of the tailing slurry all have an effect on the flocculation and settling effect. The results of the study can provide some implications for the efficient flocculation and settlement of tailings in other mines.

Study on the Effect of Flocculation and Sedimentation on the Mechanical Properties of Iron Tailing Sand

Tailings sand is the dam‐building material of the tailings dam accumulation sub‐dam, and its mechanical properties directly affect the safety and stability of the whole tailings dam. With the improvement of mineral sorting technology, the content of fine and ultrafine particles in the tailings gradually increases, which will affect the mechanical strength of tailings accumulation sub‐dam. To improve the settling effect of tailings accumulation in the Chengchao iron ore mine (China), the effect of iron tailings flocculation and settling law on the mechanical properties of tailings sand was studied. Polymerized iron sulfate (PFS) as an inorganic polymer flocculant, compared with the traditional flocculant, has a stronger flocculation and adsorption capacity, is widely used in drinking water, industrial wastewater, and domestic sewage treatment, is an anionic polyacrylamide (APAM‐800) for polymer compounds, mainly divided into nonionic, cationic, and anionic three, and is commonly used mine flocculant at home and abroad. Through different flocculants, PFS, and APAM‐800 compound flocculation and settling experiments, the effect of the flocculant‐dosing scheme on the settling rate and turbidity of clarified liquid was determined, and the change in tailings consolidation shear strength of the best dosing scheme was measured. The experimental results showed that the settling rate of iron tailings was the fastest when PFS was used in combination with APAM‐800 at 1.2 g L−1 and 0.20 g·L−1 dosages, respectively. The direct shear test results showed that the internal friction angle of tailings sand increased by 2.18°, the cohesion increased by 5.814 kPa, and the shear resistance of flocculated settled tailings increased, which can effectively improve the safety factor of tailings sand pile sub‐dam.

Bond Properties of Reinforced Concrete with Iron Tailing Sand after High Temperature Exposure

Bond Properties of Reinforced Concrete with Iron Tailing Sand after High Temperature Exposure

Mechanical Properties and Microscopic Characterization of Cemented Tailing Sand Paste Materials on Electrolytic Manganese Residue Matrix

Mechanical Properties and Microscopic Characterization of Cemented Tailing Sand Paste Materials on Electrolytic Manganese Residue Matrix

Study on the Solution of Sand Slabbing in the Tailing Sand Bin of Huanggang Iron Ore Mine

In order to improve the tailings utilization rate and realize full tailings’ filling in Huanggang iron mine in Inner Mongolia, a flocculation settlement system was added, which resulted in silting and consolidation of tailings in sand silts. Based on this, the reason for the deposition and caking of tailings was obtained through analysis, and a set of coarse and fine tailings bin filling system was proposed. The tailings of the plant were pumped to the filling station by slurry pump. Firstly, the tailings with large particle size difference were divided into coarse tailings and fine tailings by hydrocyclone so that the fine tailings entered the No. 1 sand bin and the coarse tailings entered the No. 2 sand bin. Then, flocculant was added by automatic flocculant dosing device to flocculate and settle the coarse and fine tailings, and then, it was mixed, stirred, and filled into the well. The results showed the following. (1) The particle size difference of tailings in Huanggang Iron mine increased and resulted in unstable flocs. The coarse tailings settled to the bottom of the silo before the fine tailings, and the compression time was too long, leading to the phenomenon of silting and consolidation. (2) Flocculation and settlement of coarse and fine tailings in different sand silos can avoid deposition and compaction of tailings in sand silos. (3) According to the different requirements of the concentration and ratio of the filling slurry, the proportion of coarse sand and fine sand in the filling slurry can be controlled by controlling the flow size of the coarse sand and fine sand chamber, to achieve the design of reasonable particle size composition and concentration requirements. The research results are expected to provide technical support and theoretical guidance for the construction of full tailings cemented filling system in Huanggang iron mine.

X-Ray CT Investigation on Fractal Characteristics of Fine-Grained Tailing Sand in Fujian’s Makeng: Insight into the Mesoscopic Seepage Failure

This work is aimed at revealing the mesophysical process and mechanical behaviors of fine-grained tailing sand during seepage failure. The macroscopic seepage tests combined with posttest X-ray computed tomography (CT) were employed to study the fractal characteristics of mesostructure. Results show that before and after the seepage failure of fine-grained tailing sand, fractal of pore distribution ( D pd ) and fractal dimension of pore size ( D ps ) show a relatively obvious positive correlation with porosity. Tailing particles migrate along the seepage direction during the seepage process, resulting in the gradual decrease of D pd and pore distribution area. The D ps reflects the variation characteristics of pore number distribution with different pore sizes. The increase in D ps leads to a decrease in the uniformity of pore size and an increase in the size difference between pores. The mass fractal dimension ( D m ) of fine-grained tailing sand samples ranges from 1.6472 to 1.8256. With the increase of D m , the coefficient of uniformity ( C u ) of tailing sand tends to increase. The D m method can discern the seepage failure type of fine-grained tailing sand, and it is more accurate than the traditional method. This study provides a reference for the prevention and control of the seepage failure of tailing dam.

Study on antimony cake as a technogenic raw material for the production of antimony oxides

In the process of hydrometallurgical and pyrometallurgical production of antimony at the Kadamzhai antimony plant of the Kyrgyz Republic, large-tonnage waste was generated: tailing sand, matte, slag, off-balance ore, cakes, furnace fragments, and electrolytes in salt warehouses. The waste cake is poorly studied; accordingly, the elemental and phase compositions of antimony cake have not been established. In this regard, it was noted that antimony in the cake occurs in the form of calcium antimonate and antimony hydroxide. The content of antimony in the mine tailings cakes is from 3.53 to 4.4%, with a high content of iron (27.5%) and sodium (8.86%). Based on the established elemental and phase compositions, a chemical matrix of antimony cake was compiled. The equilibrium compositions were calculated and the concentration distribution of the main elements of the cake (Fe, Na, Si, Sb) and their compounds in the gas phase was found depending on the temperature of the destruction of the solid phase. It was found that condensed antimony oxides are formed in the range of 1098 - 1348 K. Taking into account the range of temperatures for decomposition of the solid phase, a two-stage smelting of antimony cake is proposed (melting and cupellation). The conversion of antimony cake sulfides from the gas phase into a solution was carried out based on a study of the system: antimony sulfide- manganese (IV) dioxide- sulfuric acid - sodium chloride. The pH value and the redox potential (Eh) of the solution were calculated. It is noted that the sulfur compounds of antimony from the cake are converted to antimony oxychloride with the formation of antimony (III) oxide in an alkaline medium. The use of sodium chloride as a chlorinating agent of antimony sulfur compounds does not lead to the formation of toxic phosgene and hydrogen sulfide; in the solid phase, elemental sulfur is released, which is important for minimizing the technogenic load of pollutants on the environment.

High-efficiency utilization of limestone tailings: Used as cementitious materials and fine aggregate to prepare karst structure filling material

Karst areas are prone to collapse under the action of hydrodynamic forces, which has become an essential geological disaster to constrain mineral resources exploitation, underground space development, and infrastructure construction in karst areas. The cemented filling can effectively improve the stability of the karst structure, which is an effective method to control karst collapse. In this paper, limestone tailings-based cementitious materials are prepared from limestone tailings, desulfurized gypsum, slag, cement clinker, and sodium hydroxide. The impact of various factors on compressive strength in cementitious materials is evaluated through the response surface method (RSM), and the optimized ratio is as follows: cement clinker 9.97%, desulfurization gypsum 6%, limestone tailing powder 50%, blast furnace slag 34.03%, NaOH 3%. Karst filling material is prepared by cementing the limestone tailing sand with the optimized limestone tailing-based cementing material. The experiment reveals the mechanism of fineness modulus, cement-sand ratio and slurry concentration on the fluidity and strength of karst filling material. Optimization of pore structure is the key to improve the performance of filling materials. The karst filling materials efficiently utilizes limestone tailings with a utilization rate of 87.5%–93.75%.

Biocementation effect of high-efficiency urease-producing bacteria mutagenized from indigenous bacteria

A strain of urease-producing bacteria (UPB) was isolated from soil collected from the south of China, and a mutated strain with a high urease-producing efficiency was obtained through ultraviolet mutagenesis technology. The morphological characteristics of the isolated strain were examined under a transmission electron microscope. Numerous controlled trials were conducted to determine the optimal culture conditions of the mutated strain. Biocemented treatments were conducted on tailing sand with the mutated strain, and the uniaxial compressive strength of the biocemented samples was measured. SEM imaging and EDS were used to identify the type and morphological characteristics of calcium carbonate formed during biocementation. Results showed that the urease activity of the mutated strain was the highest at pH 9, and the optimum growth temperature was between 25°C and 35°C, which is similar to climate conditions in southern China. The urease activity of the mutated strain and the production of calcium carbonate were 2.18 and 1.16 times that of commercially used Sporosarcina pasteurii, respectively. The SEM images indicated that crystals with an unusual shape, such as long grains and broccoli shape, formed in the biocemented tailing sand. Raman test revealed that they were calcite. Therefore, using indigenous bacteria is practical and feasible, and ultraviolet mutagenesis technology has great potential for application in the improvement of the performance of isolated strains and their biocementation effect.

Study on the Utilization of Iron Tailings in Ultra-High-Performance Concrete: Fresh Properties and Compressive Behaviors.

In this paper iron tailing sand (TS) are used as aggerate to develop ultra high-performance concrete (UHPC). The mix proportion of UHPC is designed and TS were added by 25%, 50%, 75% and 100% (wt.%, i.e., weight percentage) to replace natural river sand. Firstly, the influence of TS on the slurry behavior was carried out. The experimental result indicates that with the continuously increasing content of TS, the workability of slurry decreases, while the air content increases. Considering the workability, the optimal replacing dosage of TS should be less than 50%. Then, tests for the hardened specimens were taken. The compressive behavior and micro-porosity deteriorate with increasing content of TS, and the compressive strength had a positive linear relationship with the workability, which indicated that the decline the compressive behavior is mainly due to the loss of flowability. Finally, autogenous shrinkages of UHPC with different TS dosage were also tested. At the same time, the micro-structure of specimens was discussed, which was deteriorate with the increasing dosage of TS. Therefore, comprehensively considering the compressive behavior, micro-structure and shrinkage behavior, as much as 50% of the aggregate could be replaced by TS when developing UHPC.