Lead-zinc Mine Tailings Research Articles

Discussion of ‘Strength Evaluation of Expansive Soil Stabilized with Lead–Zinc Mine Tailings and Cement: An Artificial Intelligence Approach’ [DOI: 10.1007/s42947-024–00450-y

Discussion of ‘Strength Evaluation of Expansive Soil Stabilized with Lead–Zinc Mine Tailings and Cement: An Artificial Intelligence Approach’ [DOI: 10.1007/s42947-024–00450-y

Strength Evaluation of Expansive Soil Stabilized with Lead–Zinc Mine Tailings and Cement: An Artificial Intelligence Approach

Strength Evaluation of Expansive Soil Stabilized with Lead–Zinc Mine Tailings and Cement: An Artificial Intelligence Approach

Mycolicibacterium arseniciresistens sp. nov., isolated from lead-zinc mine tailing, and reclassification of two Mycobacterium species as Mycolicibacterium palauense comb. nov. and Mycolicibacterium grossiae comb. nov.

A Gram-positive, acid-fast, aerobic, rapidly growing and non-motile strain was isolated from lead-zinc mine tailing sampled in Lanping, Yunnan province, Southwest China. 16S rRNA gene sequence analysis showed that the most closely related species of strain KC 300T was Mycolicibacterium litorale CGMCC 4.5724T (98.47 %). Additionally, phylogenomic and specific conserved signature indel analysis revealed that strain KC 300T should be a member of genus Mycolicibacterium, and Mycobacterium palauense CECT 8779T and Mycobacterium grossiae DSM 104744T should also members of genus Mycolicibacterium. The genome size of strain KC 300T was 6.2 Mb with an in silico DNA G+C content of 69.2 mol%. Chemotaxonomic characteristics of strain KC 300T were also consistent with the genus Mycolicibacterium. The average nucleotide identity, digital DNA-DNA hybridization and average amino acid identity values, as well as phenotypic, physiological and biochemical characteristics, support that strain KC 300T represents a new species within the genus Mycolicibacterium, for which the name Mycolicibacterium arseniciresistens sp. nov. is proposed, with the type strain KC 300T (=CGMCC 1.19494T=JCM 35915T). In addition, we reclassified Mycobacterium palauense and Mycobacterium grossiae as Mycolicibacterium palauense comb. nov. and Mycolicibacterium grossiae comb. nov., respectively.

Environmental contamination characteristics of heavy metals from abandoned lead–zinc mine tailings in China

China holds large-scale lead–zinc mineral resources; however, mining activities often cause severe contamination by heavy metals. This study systemically assessed contamination by eight heavy metals (Cu, Zn, Cd, Pb, Cr, Hg, Ni, and As) in mine tailings, soil, and groundwater from 27 contaminated sites across China. Regarding mine tailings, 1% of the mine tailing samples were hazardous waste and 20% were class II non-hazardous waste. Regarding soil, Zn and Pb showed the highest mean concentrations, at 5574.67 mg/kg and 2034.88 mg/kg, respectively. The indexes of geo-accumulation (Igeo) of eight heavy metals ranged from −3.62 to 7.67, while Zn, Pb, and Cd showed the highest environmental risk levels as the priority pollutants. The contamination levels of these heavy metals in groundwater were generally in the order of Zn>As>Pb>Ni>Cd>Cu>Hg>Cr. In this study, 20% of the soil and 10% of the groundwater samples exceeded the corresponding quality limits. The content of heavy metals in soil, groundwater, and mine tailing were positively correlated, demonstrating the main pollution source and transport paths. The pollution levels of heavy metals in soil and groundwater were listed in the foremost and moderate positions compared with similar sites from other countries, respectively. These results may help determine the pollution levels of lead–zinc mining regions and direct the remediation activities of target sites to support the environmental management of abandoned mining and tailing waste in China.

Mechanical activation of lead–zinc mine tailings as a substitution for cement in concrete construction

Use of mine tailings as a replacement for cement in concrete construction is a highly efficient method to reduce the environmental pollution of tailings’ accumulation including toxic elements, acid mine drainage, and dust emission. Thus, safe management and accurate reuse of tailings is necessary. In this research, lead–zinc mine tailings (LZTs) were used and their reactivity were improved through mechanical activation. The compressive strength, mercury intrusion porosimetry (MIP), and toxicity characteristic leaching procedure (TCLP) tests were performed on the concrete samples. The TCLP test revealed that an increase in curing days led to a significant reduction in heavy metal leaching rate (cobalt, zinc, lead, nickel, copper, arsenic, cadmium and chromium) to a permissible limit. This indicates that the application of LZTs in concrete construction would lessen environmental concerns. The MIP test indicated that mercury intrusion volume in the activated sample with 20 % cement-replacement (TA20) was lower than that of the raw sample with 20 % cement-replacement (TR20) and control (C100) samples. The results from X-ray diffraction (XRD) analysis showed that upon activating and increasing the curing time, the hatrurite converted to scawtite in samples containing activated tailings. The compressive strength results after 28 and 90 curing days revealed a rise in the strength from 16.9 MPa to 19.8 MPa for concrete samples TR20. However, upon prolonging the curing time from 28 up to 90 days, the compressive strength of the concrete samples TA20 grew from 28.35 MPa to 45.5 MPa. This indicates that the mechanical activation enhanced the hydration process and the cohesion of samples. The results of scanning electron microscopy (SEM) revealed that hydration products were also observed in concrete samples containing activated tailings. Overall, the results showed that mechanically activated LZTs, up to 40 % (by weight), can be a suitable substitute for cement in concrete production.

Preparation of self-foamed glass ceramics based on the cooperative treatment of various solid wastes: Characterization of structure-properties and analysis of self-foaming behavior

Utilization of solid waste can be a preferable waste management solution. In this study, a type of self-foamed glass ceramic material was prepared using lead zinc mine tailings, red mud, and silica sand tailings through in-situ decomposition foaming. The effect of silica sand tailings content on the pore morphology, microstructure, and basic performances of the prepared specimen was analyzed. Meanwhile, the differences in the pore morphology and self-foaming behavior of the foamed glass ceramics were discussed. The obtained results indicated that the addition of silica sand tailings facilitated the formation of the glass phase in samples, and the composition, content, and viscosity of the glass phase could be changed by adjusting the content of silica sand tailings, resulting in a uniform distribution of the formed pores. Owing to their well-distributed pore structure, foamed glass ceramics exhibit excellent comprehensive properties (light weight and high strength), making them a potential non-load-bearing material. In this study, the comprehensive properties of the sample prepared with 40 wt% silica sand tailings were determined to be the best: exhibiting the lowest bulk density (0.63 g/cm3), highest porosity (72.6%), and an applicable mechanical strength (9.7 MPa). This study utilized three solid wastes through a reasonable combination based on their chemical composition, and proposed a novel technique for the preparation of self-foaming glass ceramics via the cooperative treatment of various wastes.

The bio-immobilization of Pb(II) induced by the Chlorella–montmorillonite composite in the Ca(II) environment

The clay–microbial consortium is ubiquitous in the soil near the mining area and plays an important role in the transport of heavy metals. In this study, Chlorella sorokiniana FK was separated from lead–zinc mine tailings. The montmorillonite–Chlorella sorokiniana FK system as a typical case was applied to study Pb(II) biomineralization in the presence of usually co-existent Ca(II) and further reduce the migration and transformation of Pb(II) in the Ca(II) environment. Chlorella sorokiniana FK showed good resistance to Pb(II), and the addition of montmorillonite provided a more stable pH environment, which is conducive to the stability of Pb(II)-bearing bio-minerals. Montmorillonite created a low-biotoxicity environment in the overall process, especially less Pb(II) bio-adsorption capacity of individual Chlorella to protect the process of mineralization effectively. Batch experiment results also demonstrated that montmorillonite as the formation site of bio-minerals results in dispersed minerals on the surface of Chlorella and Chlorella–MMT composite, which is beneficial to the survival of Chlorella. Moreover, Pb(II)-bearing phosphate minerals tended to form in the Ca(II) environment rather than without Ca(II). This study demonstrated the mechanism of Pb(II) immobilization induced by Chlorella in the Ca(II) environment, further presenting a green, sustainable, and effective strategy for Pb(II) bio-immobilization combining clay minerals and microorganisms.

Microstructural and compaction characteristics of tropical black clay soil subgrade modified with lead-zinc mine tailings

Lead–Zinc Mine tailings (LZMT) are wastes generated after the extraction of lead and zinc from mined mineral ore, whose disposal mechanism is gradually becoming environmentally unfriendly. For effective recycling of LZMT, this present study utilized a combination of LZMT and Portland limestone cement (PLC) to improve the compaction and microstructural characteristics of tropical black clay soil (TBCS) for use in pavement design and construction. The LZMT and PLC were added to the expansive soil in varying proportions with mix ratios generated from Taguchi orthogonal array. The result obtained for the compaction characteristics showed that the maximum dry density (MDD) increased significantly when a combination of 20% LMZT and 4% PLC were blended with the expansive soil. The increase in the MDD was attributed to the formation of cementitious compounds. In addition, the optimum mix ratio obtained from the unconfined compressive strength of the TBCS, was used for the evaluation of the pore structure characteristics which included porosity, tortuosity and permeability. The result obtained from the analysis that was implemented with a combination of fractal geometry and Bradley and Roth adaptive thresholding image segmentation technique, indicates the possibility of a slight reduction in the strength properties of the modified soil due to its high level of porosity. Also, the permeability and tortuosity values obtained from the present study suggest a slight increase in the permeability of the modified soil-additive mixtures which may not be unconnected to the occurrence of pozzolanic reaction that resulted in the agglomeration and flocculation of the LZMT-PLC modified TBCS. Furthermore, microstructural analysis was executed on the modified TBCS and LZMT using Fourier transform infrared spectroscopy (FTIR) and scanning electron microscopy (SEM). The result from the FTIR analysis indicates the pozzolanic character of LZMT in the presence of Si–O and Al–O tension bond with the bonds around 1000 cm−1 wavenumber, while the SEM analysis reveals the formation of a cementitious compound in the modified expansive soil-LZMT-PLC mixture.

Utilization of lead–zinc mine tailings as cement substitutes in concrete construction: Effect of sulfide content

Production of acid mine drainage and emission of heavy metals from tailings, especially sulfide tailings, to the environment is one of the serious challenges in the management of mine tailings. The use of cementation process and replacement of cement with mine tailings in the manufacture of concrete is one of the practical approaches to the management of mine tailings. In this study, two different lead-zinc mine tailings (T1 with 0.4% and T2 with 19% sulfide content) were separately used as a cement substitution in concrete construction. Toxicity characteristic leaching procedure (TCLP), acid generation potential, compressive strength tests, and mercury intrusion porosimetry (MIP) were conducted on the constructed concrete samples. The TCLP test results revealed that with increasing the curing time of the samples, the leaching rate of toxic metals (arsenic, cadmium, chromium, cobalt, nickel, copper, zinc, and lead) in all samples was reduced to lower than the permissible criteria, indicating the good stabilization of heavy metals in concrete samples. The MIP test results also revealed that with increasing the curing days and subsequently the hydration process, the intruded mercury volume decreased, indicating that heavy metals were stabilized in concrete samples. The compressive strength test findings revealed that in constructed concrete containing 20% cement-replacing T1, with increasing the curing time of the sample from 28 to 90 days, the compressive strength increased from 16.9 to 19.8 MPa, and the leaching rate of heavy metals decreased from 39.64 to 23.65 μg/L,. In addition, in the sample with 20% T2, the compressive strength increased from 10.59 to 16.4 MPa, and the leaching rate of heavy metals decreased from 44.65 to 26.5 μg/L. Comparing the Scanning Electron Microscope (SEM) and Energy Dispersive X-ray analyzer (EDX) results, it was found that the Ca/Si ratio was lower in the samples prepared with mine tailings compared to the control, indicating insufficient amount of calcium available to form the main hydration product (C–S–H). Therefore, less C–S–H gel was formed in these samples. Also, according to the elemental distribution analysis, it was revealed that other heavy metals were scattered throughout the concrete matrix and stabilized in the concrete structure by forming new compounds. In general, it could be concluded that cement replacement with lead-zinc mine tailings up to 20% without the use of any improvement technique may be possible. Further, the formation of hydration products affected by high sulfide content and causes the production of sulfide salts that attack the concrete sample over time, thereby reducing cementitious properties and strength.

Modification of carbonate-activated binder for lead-zinc mine tailings based cemented paste backfill

CPB promotes a green development of the mining industry. At the same time, the high cost of OPC limits the large-scale application of CPB. This study aimed to use carbonate-activated binders as cementitious materials in LZT based CPB. The binder was modified by CLDH and/or HM when considering the carbonate-activated binder's low reaction rate and bad performance. The effect of 3–5 wt% CLDH and 0.5–1 wt% HM on the reaction kinetics and phase assembles of Na2CO3-activated slag was investigated via isothermal calorimetry, XRD, and TG analysis. Flowability, setting time, and compressive strength of CPB samples were used to assess the feasibility of the binder in CPB. The immobilization effect and leaching mechanism of heavy metals from the CPB samples were then evaluated via TCLP, sequential extraction test, and semi-dynamic leaching. The incorporation of CLDH and HM accelerated binder reaction through consuming CO32−. The coupling addition of 3 wt% CLDH and 0.5 HM presented the best performance, reaching about 2.29 MPa at 28 days. This value was higher than OPC-based CPB samples by around 10%.

Leaching of heavy metals from lead-zinc mine tailings and the subsequent migration and transformation characteristics in paddy soil

The leaching of heavy metals (HMs) from lead-zinc mine tailings caused by natural precipitation and the subsequent migration and transformation characteristics in paddy soil were investigated using simulative experiments. The contents of HMs in the leachate from lead-zinc mine tailings increased with the increasing of liquid-to-solid ratio. Significant differences of contents under the same rainfall were found among different HMs (P < 0.01). The increasing rates of the concentrations for Mn and Zn in leachate were much higher than the other selected HMs. The leaching results of all HMs were well fitted by the DoseResp equation, indicating that the leaching processes are controlled by multiple factors. When the paddy soil was exposed to lead-zinc mine tailings, the HMs could accumulate significantly in the paddy soil, and their contents increased with the simulated time. The average vertical migration rates (mg kg−1 cm−1 d−1) of HMs in the paddy soil during the four months was ranked in the order of Zn (9.0✕10−2) > Mn (8.1✕10−2) > Cu (1.8✕10−2) > Pb (1.6✕10−2) > Cd (2.7✕10−4) > As (2.4✕10−4). Compared with the other HMs, Mn and Zn can be more easily leached from lead-zinc mine tailings, then migrate into deeper layers in paddy soil. The proportions in five chemical fractions of HMs varied significantly with the impact of lead-zinc mine tailings. The Zn, Cu, and As were mainly presented in residual fraction, while Pb, Mn, and Cd were mainly presented in carbonate-bound, Fe/Mn oxides-bound, and exchangeable fractions, respectively. The risk assessment code results showed that Zn, Mn, Cu, and As posed medium risk, while Pb and Cd posed an extremely high risk to the paddy soil environment. It's found that lead-zinc mine tailings could significantly enhance the ecological risk associated with HMs in the paddy soil.

Spent mushroom compost and calcium carbonate modification enhances phytoremediation potential of Macleaya cordata to lead-zinc mine tailings

Phytoremediation is an essential technique for mines' ecological restoration. Modifiers addition can alleviate the stress of heavy metals to plants and enhanced remediation efficiency. Herein, spent mushroom compost (SMC) and calcium carbonate (CaCO3) were added to lead-zinc mine tailings to reveal the mechanism of Macleaya cordata adaptive to heavy metals stress. Pot experiments were conducted in 100% tailing (T), 90% tailing + 5% SMC + 5% CaCO3 (T+), and 100% natural soil (NS). The results indicate that SMC and CaCO3 amendments could improve the structure and fertility of tailings, and promote the growth of M. cordata, increase the content of heavy metals accumulated in plants, enhance the synthesis of chlorophyll and increas the content of soluble protein in leaves; enhance the activities of antioxidase, that can protectcelluar components from oxidative damage. Moreover, most of Pb, Zn, and Cd existed in the cell wall and soluble components, adding SMC and CaCO3 could promote the conversion of Pb, Zn, and Cd to chemical forms with less toxicity and migratory capability. The results of transmission electron microscopy (TEM) and Fourier transform infrared spectrometer (FTIR) showed that SMC and CaCO3 could protect the structural integrity of cells and increase the contents of –OH, –COOH functional groups that can bind to heavy metals in cells. The addition of SMC and CaCO3 can alleviate the stress of heavy metals on M. cordata, enhancing its adaptability to heavy metals and phytoremediation capacity.

Modification of Carbonate-Activated Binder for Lead-Zinc Mine Tailings Based Cemented Paste Backfill

Modification of Carbonate-Activated Binder for Lead-Zinc Mine Tailings Based Cemented Paste Backfill

Photosynthesis Performance and Antioxidative Enzymes Response of Melia azedarach and Ligustrum lucidum Plants Under Pb-Zn Mine Tailing Conditions.

Lead–zinc (Pb–Zn) mine tailings pose a great risk to the natural environment and human health because of their high toxicity. In this study, the responses of photosynthesis, chlorophyll fluorescence, and antioxidative enzyme of Melia azedarach and Ligustrum lucidum in the soil contaminated by Pb–Zn mine tailings were investigated. Results showed that Pb–Zn mine tailings significantly reduced net photosynthetic rates and leaf photosynthetic pigment content of both trees, and the reduction of net photosynthetic rates was mainly caused by their biochemical limitation (BL). The chlorophyll fluorescence parameters from Pb–Zn tailing stressed leaves indicated that Pb–Zn tailings affected PSII activity which was evident from the change values of energy fluxes per reaction center (RC): probability that an electron moves further than QA− (ETO/TRO), maximum quantum yield for primary photochemistry (TRO/ABS), the density of PSII RC per excited cross-section (RC/CSO), the absorption of antenna chlorophylls per PSII RC (ABS/RC), and the turnover number of QA reduction events (N). Pb–Zn mine tailings also affected the oxidation and reduction of PSI, which resulted in a great increase of reactive oxygen species (ROS) contents and then stimulated the rate of lipid peroxidation. Both trees exhibited certain antioxidative defense mechanisms as elevated superoxide dismutase (SOD), peroxidase (POD), and catalase (CAT) activities, then declined under high level of Pb–Zn tailing treatment. Comparatively, L. lucidum showed less extent effect on photosynthesis and higher antioxidative enzyme activities than M. azedarach; thus L. lucidum was more tolerant than M. azedarach at least under the described Pb–Zn tailing treatment. These results indicate that the effect of Pb–Zn mine tailings on photosynthesis performance mainly related to imbalance of the PSII activity and PSI redox state in both trees. We propose that M. azedarach and L. lucidum could relieve the oxidative stress for phytoremediation under the appropriate Pb–Zn mine tailing content.

In situ stabilization of heavy metals in a tailing pond with a new method for the addition of mineral stabilizers-high-pressure rotary jet technology.

As the demand for metal minerals grows, the number of mine tailings increases dramatically worldwide. Toxic heavy metals (HMs) in tailings tend to migrate into the environment and cause serious damage to the surroundings. Possible eco-friendly solutions for the in situ stabilization of HMs in tailing ponds are required to reduce their mobility. Leaching tests were performed with attapulgite, zeolite, and bentonite to determine which stabilizer is more efficient. As a result, attapulgite has more significant effect with certain dose on metal mine tailings than zeolite or bentonite, especially in a strongly acidic environment. In addition, an in situ stabilization experiment was performed by adding a stabilizer to a lead-zinc mine tailing pond with high-pressure rotary jet technology. The field experiment indicated that the concentrations of HMs in the leachate substantially decreased (30.5% for Cr, 43.1% for Cu, 87.8% for Zn, 82.9% for Cd, and 42.4% for Pb) after the HMs were stabilized by high-pressure rotary jet technology. A set of parameters for the rotary jet process was obtained when the in situ stabilization experiment was carried out.

Promoting the performance of one-part alkali-activated slag using fine lead-zinc mine tailings

The feasibility of using fine lead–zinc mine tailings to improve the performance of one-part alkali-activated slag (AAS) with low alkali dosage (1.5 Na2O wt.%) is investigated. The compressive strength of one-part AAS increases with the increase of fine tailings at the early age (≤7 d), and then slightly decreases after 28 d of curing. Two distinguished reaction stages with two dormant periods are identified in all samples, regardless of the content of fine tailings. The incorporation of fine tailings accelerates the second reaction stage, but has little effect on the first reaction stage. The pH value of the pore solution in all samples increases with the reaction time (≤14 d), and those with a high content of fine tailings give relatively high alkalinity values at all curing ages. The incorporation of fine lead–zinc mine tailings enhances the compressive strength of one-part AAS, which is mainly associated with its roles of improving the pH value in pore solutions and accelerating the reaction of binders.

Effects of peat on plant growth and lead and zinc phytostabilization from lead-zinc mine tailing in southern China: Screening plant species resisting and accumulating metals

In order to investigate the toxicity-resistance of eighteen Chinese native plants in lead (Pb)-zinc (Zn) mine tailings, we categorized their resistance to Pb and Zn, and tested their potential for phytoremediation effectiveness of Pb and Zn. Fourteen woody plant species belonging to 12 families, and 4 herbaceous species belonging to 4 families, were grown in pots with mixtures of 100% tailing +0% peat (CK), 90% tailing +10% peat (A1), and 80% tailing + 20% peat (A2), respectively. Plant height and biomass, chlorophyll content, and Pb and Zn contents of non-rhizosphere spoil mixtures and plant tissues were measured. Fifteen of the plants grew in all three spoil mixtures. Both A1 and A2 had higher plant height and biomass increment and chlorophyll contents than CK. The content of Pb and Zn in plant shoots and roots was CK > A1 > A2. The value of BCF less than 0.1, compared to 1, was a more precise classification basis for plants excluding metals. Screening for Pb and Zn resistant plants and their bioremediation potential produced the following candidate species: Sapium sebiferum, Salix matsudana, Hibiscus cannabinus, Corchorus capsularis, Ricinus communis, and Populus nigra. These species were highly Pb and Zn tolerant species, with notable growth characteristics and capacities to bioaccumulate Pb and Zn from the mine tailings. Compared to CK, the removal of Pb and Zn from non-rhizosphere spoil increased by an average of 9.64% and 9.6%, respectively in A1, but decreased in A2. The results indicated candidate species and 10% peat addition in the tailing were significant in phytoremediation of Pb and Zn regarding environmental safety.

Isolation and characterization of aerobic, culturable, arsenic-tolerant bacteria from lead-zinc mine tailing in southern China.

Bioremediation of arsenic (As) pollution is an important environmental issue. The present investigation was carried out to isolate As-resistant novel bacteria and characterize their As transformation and tolerance ability. A total of 170 As-resistant bacteria were isolated from As-contaminated soils at the Kangjiawan lead-zinc tailing mine, located in Hunan Province, southern China. Thirteen As-resistant isolates were screened by exposure to 260mM Na2HAsO4·7H2O, most of which showed a very high level of resistance to As5+ (MIC ≥ 600mM) and As3+ (MIC ≥ 10mM). Sequence analysis of 16S rRNA genes indicated that the 13 isolates tested belong to the phyla Firmicutes, Proteobacteria and Actinobacteria, and these isolates were assigned to eight genera, Bacillus, Williamsia, Citricoccus, Rhodococcus, Arthrobacter, Ochrobactrum, Pseudomonas and Sphingomonas. Genes involved in As resistance were present in 11 of the isolates. All 13 strains transformed As (1mM); the oxidation and reduction rates were 5-30% and 10-51.2% within 72h, respectively. The rates of oxidation by Bacillus sp. Tw1 and Pseudomonas spp. Tw224 peaked at 42.48 and 34.94% at 120h, respectively. For Pseudomonas spp. Tw224 and Bacillus sp. Tw133, the highest reduction rates were 52.01% at 48h and 48.66% at 144h, respectively. Our findings will facilitate further research into As metabolism and bioremediation of As pollution by genome sequencing and genes modification.

Phase evolution, pore morphology and microstructure of glass ceramic foams derived from tailings wastes

In the direction of dealing with solid hazards, preparing glass ceramic foam materials has become a practicable technique due to its environmental-friendly and economical characteristic. Here, we have successfully prepared glass ceramic foams with excellent combination of properties by utilizing lead-zinc mine tailings (LZMT), fly ash (FA) and red mud (RM) as the major component. The influence of sintering temperature on phase evolution, pore morphology, microstructure, physical properties and chemical stability of glass ceramic foam was investigated. The results reveal all above performances exhibit temperature-dependent character, with increasing sintering temperature, the performances enhance first and then deteriorate, the optimal porosity and compressive strength value for the prepared sample can be well achieved at the temperature of 980 °C. Liquid phase was formed during the heat treatment process and resulted in the variation of pore structure. According to SEM image and EDS spectra, the liquid phase may be the Ca-Al-Si-O system glass with less network modifier. The experiment results indicated that glass ceramic foams can be obtained by using solid wastes with different chemical compositions, better yet, it features with economic efficiency to solve the industrial solid wastes problems.

Acid production potentials of massive sulfide minerals and lead-zinc mine tailings: a medium-term study.

Weathering of sulfide minerals is a principal source of acid generation. To determine acid-forming potentials of sulfide-bearing materials, two basic approaches named static and kinetic tests are available. Static tests are short-term, and easily undertaken within a few days and in a laboratory. In contrast, kinetic tests are long-term procedures and mostly carried out on site. In this study, experiments were conducted over a medium-term period of 2 months, not as short as static tests and also not as long as kinetic tests. As a result, pH and electrical conductivity oscillations as a function of time, acid-forming potentials and elemental contents of synthetically prepared rainwater leachates of massive sulfides and sulfide-bearing lead-zinc tailings from abandoned and currently used deposition areas have been determined. Although the lowest final pH of 2.70 was obtained in massive pyrite leachate, massive chalcopyrite leachate showed the highest titrable acidity of 1.764 g H2SO4/L. On the other hand, a composite of currently deposited mine tailings showed no acidic characteristic with a final pH of 7.77. The composite abandoned mine tailing leachate had a final pH of 6.70, close to the final pH of massive galena and sphalerite leachates, and produced a slight titrable acidity of 0.130 g H2SO4/L.