scholarly journals The Solidification of Lead-Zinc Smelting Slag through Bentonite Supported Alkali-Activated Slag Cementitious Material

2019 ◽  
Vol 16 (7) ◽  
pp. 1121 ◽  
Author(s):  
Yanhong Mao ◽  
Faheem Muhammad ◽  
Lin Yu ◽  
Ming Xia ◽  
Xiao Huang ◽  
...  
Keyword(s):  
Compressive Strength ◽  
Water Glass ◽  
Cementitious Material ◽  
Curing Temperature ◽  
Solid Ratio ◽  
Zinc Smelting ◽  
Lead Zinc ◽  
Smelting Slag ◽  
Alkali Activated ◽  
Zinc Smelting Slag

The proper disposal of Lead-Zinc Smelting Slag (LZSS) having toxic metals is a great challenge for a sustainable environment. In the present study, this challenge was overcome by its solidification/stabilization through alkali-activated cementitious material i.e., Blast Furnace Slag (BFS). The different parameters (water glass modulus, liquid-solid ratio and curing temperature) regarding strength development were optimized through single factor and orthogonal experiments. The LZSS was solidified in samples that had the highest compressive strength (after factor optimization) synthesized with (AASB) and without (AAS) bentonite as an adsorbent material. The results indicated that the highest compressive strength (AAS = 92.89MPa and AASB = 94.57MPa) was observed in samples which were prepared by using a water glass modulus of 1.4, liquid-solid ratio of 0.26 and a curing temperature of 25 °C. The leaching concentrations of Pb and Zn in both methods (sulfuric and nitric acid, and TCLP) had not exceeded the toxicity limits up to 70% addition of LZSS due to a higher compressive strength (>60 MPa) of AAS and AASB samples. While, leaching concentrations in AASB samples were lower than AAS. Conclusively, it was found that the solidification effect depends upon the composition of binder material, type of leaching extractant, nature and concentration of heavy metals in waste. The XRD, FTIR and SEM analyses confirmed that the solidification mechanism was carried out by both physical encapsulation and chemical fixation (dissolved into a crystal structure). Additionally, bentonite as an auxiliary additive significantly improved the solidification/stabilization of LZSS in AASB by enhancing the chemical adsorption capacity of heavy metals.

scholarly journals The Utilization of Alkali-Activated Lead–Zinc Smelting Slag for Chromite Ore Processing Residue Solidification/Stabilization

2021 ◽  
Vol 18 (19) ◽  
pp. 9960
Author(s):  
Lin Yu ◽  
Lu Fang ◽  
Pengpeng Zhang ◽  
Shujie Zhao ◽  
Binquan Jiao ◽  
...  
Keyword(s):  
Compressive Strength ◽  
Hazardous Waste ◽  
Chromite Ore Processing Residue ◽  
Chromite Ore ◽  
Ore Processing ◽  
Zinc Smelting ◽  
Lead Zinc ◽  
Smelting Slag ◽  
Alkali Activated ◽  
Zinc Smelting Slag

Lead–zinc smelting slag (LZSS) is regarded as a hazardous waste containing heavy metals that poses a significant threat to the environment. LZSS is rich in aluminosilicate, which has the potential to prepare alkali-activated materials and solidify hazardous waste, realizing hazardous waste cotreatment. In this study, the experiment included two parts; i.e., the preparation of alkali-activated LZSS (pure smelting slag) and chromite ore processing residue (COPR) solidification/stabilization. Single-factor and orthogonal experiments were carried out that aimed to explore the effects of various parameters (alkali solid content, water glass modulus, liquid–solid ratio, and initial curing temperature) for alkali-activated LZSS. Additionally, compressive strength and leaching toxicity were the indexes used to evaluate the performance of the solidified bodies containing COPR. As a result, the highest compressive strength of alkali-activated LZSS reached 84.49 MPa, and when 40% COPR was added, the strength decreased to 1.42 MPa. However, the leaching concentrations of Zn and Cr from all the solidified bodies were far below the critical limits (US EPA Method 1311 and China GB5085.3-2007). Heavy-metal ions in LZSS and COPR were immobilized successfully by chemical and physical means, which was detected by analyses including environmental scanning electron microscopy with energy-dispersive spectrometry, Fourier transform infrared spectrometry, and X-ray diffraction.

scholarly journals Preparation of Cementitious Material Using Smelting Slag and Tailings and the Solidification and Leaching of Pb2+

2015 ◽  
Vol 2015 ◽  
pp. 1-7 ◽  
Author(s):  
Dan Zhang ◽  
Shiliu Shi ◽  
Chengbiao Wang ◽  
Xiaocong Yang ◽  
Lijie Guo ◽  
...  
Keyword(s):  
Cementitious Materials ◽  
Cementitious Material ◽  
Cement Clinker ◽  
Lead Ion ◽  
Leaching Kinetics ◽  
Zinc Smelting ◽  
Lead Zinc ◽  
Smelting Slag ◽  
Kinetics Of ◽  
Zinc Smelting Slag

The composite cementitious materials were prepared with lead-zinc tailings, lead-zinc smelting slag, and cement clinker. The effect of material ratio on the mechanical properties, the phase analysis, and microstructures were investigated. The effect of the pH and stripping time on the leaching amount of lead ion was discussed. The results show that the additive amount of the tailings should be minimized for the cementitious materials meeting the strength requirements, controlled within 10%. The leaching amount of cementitious materials remains low in a larger range of pH, which can effectively reduce the leaching of heavy metal lead. The leaching kinetics of lead ions in the three kinds of samples could be better described by the pseudo-second-model.

Self-cementation solidification of heavy metals in lead-zinc smelting slag through alkali-activated materials

2020 ◽  
Vol 249 ◽  
pp. 118756 ◽  
Author(s):  
Pengpeng Zhang ◽  
Faheem Muhammad ◽  
Lin Yu ◽  
Ming Xia ◽  
Huirong Lin ◽  
...  
Keyword(s):  
Heavy Metals ◽  
Zinc Smelting ◽  
Lead Zinc ◽  
Smelting Slag ◽  
Alkali Activated ◽  
Zinc Smelting Slag

scholarly journals Sodium Silicate Gel Effect on Cemented Tailing Backfill That Contains Lead-Zinc Smelting Slag at Early Ages

2018 ◽  
Vol 2018 ◽  
pp. 1-6 ◽  
Author(s):  
Lijie Guo ◽  
Wenchen Li ◽  
Xiaocong Yang ◽  
Wenyuan Xu
Keyword(s):  
Pore Structure ◽  
Sodium Silicate ◽  
Mechanical Test ◽  
Strength Development ◽  
Gel Effect ◽  
Zinc Smelting ◽  
Lead Zinc ◽  
Smelting Slag ◽  
Cementitious Activity ◽  
Zinc Smelting Slag

This paper presents the results of an experimental study on the priming effect of sodium silicate gel (SS) on cemented tailing backfill (CTB) that contains lead-zinc smelting slag. CTB and cemented paste (CP) containing lead-zinc smelting slag samples with SS of 0 and 0.4% of the mass of the slag were prepared and cured at 20°C for 1, 3, 7, and 28 days. Mechanical test and pore structure analyses were performed on the studied CTB samples, microstructural analyses (X-ray diffraction analysis and thermal gravity analysis) were performed on the studied CP samples, whereas the electrical conductivity of CTB was monitored. The results reveal that SS has a significant positive effect on cementitious activity of binder mixed by cement and lead-zinc smelting slag. This activation leads to the acceleration of binder hydration process, the formation of more cement hydration products in the CTBs, and the refinement of their pore structure, which is favorable for the strength development of CTB.

scholarly journals Influence of Particle Size on Compressive Strength of Alkali Activated Refractory Materials

Materials ◽  
2020 ◽  
Vol 13 (10) ◽  
pp. 2227 ◽  
Author(s):  
Barbara Horvat ◽  
Vilma Ducman
Keyword(s):  
Particle Size ◽  
Compressive Strength ◽  
Mechanical Strength ◽  
Time Dependence ◽  
Water Glass ◽  
Curing Temperature ◽  
Refractory Materials ◽  
Alkali Activated

Influence of particle size on the mechanical strength of alkali activated material from waste refractory monolithic was investigated in this study. Precursor was chemically and mineralogically analysed, separated on 4 fractions and alkali activated with Na-water glass. Alkali activated materials were thoroughly investigated under SEM and XRD to evaluate the not predicted differences in mechanical strength. Influence of curing temperature and time dependence at curing temperatures on mechanical strength were investigated in the sample prepared from a fraction that caused the highest compressive strength.

Experimental Investigations on Alkali-Activated Slag Cementitious Material

2014 ◽  
Vol 672-674 ◽  
pp. 1823-1827
Author(s):  
Xiao Wei Sun ◽  
Wan Yang Niu ◽  
Ling Ling Wang
Keyword(s):  
Water Glass ◽  
Setting Time ◽  
Cementitious Material ◽  
Curing Temperature ◽  
Experimental Investigations ◽  
Strength Increase ◽  
Curing Conditions ◽  
Alkali Activated Slag ◽  
Activated Slag ◽  
Alkali Activated

These are many factors that can influence the properties of alkali-activated slag cementitious material, such as the modulus and content of water glass, water-cement ratio, curing conditions, and so forth. The rules that how these factors affect setting time and strength of the material are systematically discussed in the paper. It is found that the setting time of the material depends on the concentration of alkaline ions in solution; The material will have the best strength when the modulus and content of water glass are 1.4 and 8%, respectively. The curing temperature increase will be helpful to compressive strength increase.

Solidification/stabilization of lead-zinc smelting slag in composite based geopolymer

2019 ◽  
Vol 209 ◽  
pp. 1206-1215 ◽  
Author(s):  
Ming Xia ◽  
Faheem Muhammad ◽  
Linghao Zeng ◽  
Shan Li ◽  
Xiao Huang ◽  
...  
Keyword(s):  
Zinc Smelting ◽  
Lead Zinc ◽  
Smelting Slag ◽  
Zinc Smelting Slag

scholarly journals Machine Learning Approaches for Prediction of the Compressive Strength of Alkali Activated Termite Mound Soil

2021 ◽  
Vol 11 (11) ◽  
pp. 4754
Author(s):  
Assia Aboubakar Mahamat ◽  
Moussa Mahamat Boukar ◽  
Nurudeen Mahmud Ibrahim ◽  
Tido Tiwa Stanislas ◽  
Numfor Linda Bih ◽  
...  
Keyword(s):  
Compressive Strength ◽  
Construction Materials ◽  
Curing Temperature ◽  
Sustainable Construction ◽  
Support Vector ◽  
Learning Approaches ◽  
Artificial Neural Network Ann ◽  
Curing Regime ◽  
Alkali Activated

Earth-based materials have shown promise in the development of ecofriendly and sustainable construction materials. However, their unconventional usage in the construction field makes the estimation of their properties difficult and inaccurate. Often, the determination of their properties is conducted based on a conventional materials procedure. Hence, there is inaccuracy in understanding the properties of the unconventional materials. To obtain more accurate properties, a support vector machine (SVM), artificial neural network (ANN) and linear regression (LR) were used to predict the compressive strength of the alkali-activated termite soil. In this study, factors such as activator concentration, Si/Al, initial curing temperature, water absorption, weight and curing regime were used as input parameters due to their significant effect in the compressive strength. The experimental results depict that SVM outperforms ANN and LR in terms of R2 score and root mean square error (RMSE).

scholarly journals Alkali-Activated Zeolite 4A Granules—Characterization and Suitability Assessment for the Application of Adsorption

Crystals ◽  
2021 ◽  
Vol 11 (4) ◽  
pp. 360
Author(s):  
Pauls P. Argalis ◽  
Laura Vitola ◽  
Diana Bajare ◽  
Kristine Vegere
Keyword(s):  
Compressive Strength ◽  
Raw Materials ◽  
Physical And Mechanical Properties ◽  
Morphological Properties ◽  
Solid Ratio ◽  
Suitability Assessment ◽  
Bet Analysis ◽  
Zeolite 4A ◽  
Compressive Strength Test ◽  
Alkali Activated

A major problem in the field of adsorbents is that binders (kaolin clay, bentonite) introduced to bind zeolites and ensure the needed mechanical strength, are not able to sorb gases like CO2 and N2, and decrease the overall adsorption capacity. To solve this problem, one of the pathways is to introduce a binder able to sorb such gases. Thus, in this study, the physical and mechanical properties of a novel binder based on metakaolin and its composite with zeolite 4A in the granular form were studied. Metakaolin was used as a precursor for alkali-activated binder, which was synthesized using an 8M NaOH activation solution. Raw materials were characterized using granulometry, X-ray diffraction (XRD), and differential thermal analysis (DTA); and final products were characterized using density measurements, a compressive strength test, XRD, Brunauer–Emmett–Teller (BET) analysis, and scanning electron microscopy (SEM). Alkali-activated metakaolin was found to be efficient as a binding material when data for morphological properties were analyzed. A relationship was observed—by increasing the liquid-to-solid ratio (L/S), compressive strength decreased. Zeolite granule attrition was higher than expected: 2.42% and 4.55% for ZG-0.8, 3.64% and 5.76% for ZG-1.0, and 2.73% and 4.85% for ZG-1.2, measured at 4 and 5 atmospheres, respectively.

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