Rational Utilization of Fine Unclassified Tailings and Activated Blast Furnace Slag with High Calcium

Zhou, Yanlong; Deng, Hongwei; Liu, Jixiang

doi:10.3390/min7040048

Cited by 13 publications

(10 citation statements)

References 36 publications

(42 reference statements)

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“…Sodium silicate is indeed a viscous material that is usually used to activate pozzolanic materials such as slag and fly ash. The chemical compound has many applications, namely, in waste treatment [27], mine tailings [28][29][30][31], sand fill [32], and other construction materials [33][34][35].…”

Section: Introductionmentioning

confidence: 99%

Compressive Strength Characteristics of Cemented Tailings Backfill with Alkali-Activated Slag

et al. 2018

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With the use of glauberite mineral (GM) and sodium hydroxide (SH) alkaline catalysts to stimulate slag powder’s internal cementation activity and incorporate the two fine-grained solid wastes, such as quicklime (Q) and desulfurized ash (DA), a new cementitious material suitable for mine tailings was developed to replace traditional ordinary Portland cement (OPC) for reducing cement-related costs. A series of uniaxial compressive strength (UCS) tests were carried out on cemented tailings backfill (CTB) samples containing different activators. The results showed that (1) the highest UCS values of 14-day and 28-day cured CTB samples were 1.259 MPa and 2.429 MPa, respectively, and the effect of different activator types was in the order of SH > GM > DA > Q and SH > GM > Q > DA; (2) the relationship between UCS and activator dosages followed the function y = ax3 − bx2 + cx − d. Compared with the OPC 32.5 R cemented samples, the minimum strength growth factor was 1.45, and the maximum reached 2.03; (3) the optimal proportion of DA slag formula was 4.5% or 5.0% Q, 19% DA, 2.5% GM, and 0.7% SH. The aforesaid new cementitious materials met the mine’s UCS requirements with a relatively low cost (17.04–17.20 €/ton) and solved the stacking problem of solid wastes on the surface well. Ultimately, this study provides a useful reference for the development of mineral binders.

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Section: Introductionmentioning

confidence: 99%

Compressive Strength Characteristics of Cemented Tailings Backfill with Alkali-Activated Slag

et al. 2018

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“…Based on the recommended parameters, the amount of cement is greatly reduced in the CPB. e total cost of the backfill materials is 3.32 USD/m 3 , which is only 29%-41% of CPB-based DPG-cement [26,27] and 56% of CPB-based total tailings [35]. If an effective filling rate of 90% is taken into account as a rough calculation, then there will be a consumption of 300,000 tonnes of HPG and 50,000 tonnes of PS for CPB per year.…”

Section: Application Evaluationmentioning

confidence: 99%

“…Based on these experiment schemes, the HPG, PS, quicklime, cement, and water were first weighed separately, and then those materials were thoroughly mixed and stirred for 5 minutes by the electric mixer. Secondly, the uniformly stirred slurry was poured into the standard triunit models with a size of 70.7 × 70.7 × 70.7 mm 3 [35], and then, the slurry was compacted with a stir bar and the mold was vibrated to keep the slurry higher than the top surface 6-8 mm of the mold. While the surface moisture was slightly dried, higher slurry is scraped from the mold to keep the surface smooth.…”

mentioning

confidence: 99%

Cost-Effective Treatment of Hemihydrate Phosphogypsum and Phosphorous Slag as Cemented Paste Backfill Material for Underground Mine

Xue

Kang

et al. 2019

Advances in Materials Science and Engineering

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The environmental pollution caused by the discharge of phosphogypsum (PG) and phosphorous slag (PS) is a common issue for all countries. In order to fully utilize hemihydrate PG (HPG) and PS and treat goafs in mines, the HPG and PS were used as cementitious materials for cemented paste backfill (CPB). The physical and chemical properties of HPG and PS were first analyzed, and then, the characteristics of CPB were evaluated through fluidity tests, gas detection, uniaxial compressive strength (UCS) tests, bleeding tests, and scanning electron microscopy (SEM). After this, the underground environmental impact of CPB-based HPG and PS was investigated through a dynamic leachability experiment. The results show that (1) the UCS of CPB increases with the increase of the HPG content and mass fraction, and the addition of 3% quicklime can eliminate CO2, H2S, and SO2 generated from the slurry of CPB-based HPG-PS; (2) the addition of 3% quicklime and 5% cement to the HPG-PS mixtures can offset the strength loss of CPB in the late curing stage; (3) the UCS of the recommended specimen reaches 1.15–3.32 MPa after curing from 7 to 28 days, with their slump values varying from 15 mm to 26 mm, and the bleeding rates between 0.87% and 1.15%, which can meet the technical requirements of mining methods; (4) the UCS of CPB is the result of the cohydration reaction of hemihydrate gypsum (HG) in HPG and active Al2O3 and SiO2 in PS; and (5) the leaching indexes meet Category IV of the Chinese Groundwater Quality Standard (DZ/T 0290-2015). The results of this investigation provide a cost-efficient way for the efficient mining of phosphate resources and the comprehensive utilization of HPG and PS.

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“…After intensive mixing, the mixed slurry was poured into metal cubes with dimensions of 70.7 mm × 70.7 mm × 70.7 mm, followed by a rest period (48 h) to obtain cubic samples. Following this, the CTB samples were removed from the cubic molds and then placed and cured in a relative temperature at 20 ± 5 • C and humidity room at 92 ± 5% for the final curing periods of 3, 7, and 28 days [54]. Before each testing, the size of CTB samples was measured carefully and recorded.…”

Section: Ctb Sample Preparationmentioning

confidence: 99%

Evaluation of Viscosity, Strength and Microstructural Properties of Cemented Tailings Backfill

2018

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In this study, the particle size distribution and chemical composition of gold mine tailings were examined experimentally. A series of viscosity and uniaxial compressive strength (UCS) tests were used to study the relations between the viscosity of cemented tailings backfill (CTB) slurry, the solid content (SD), and the cement-to-tailings ratio (c/t). Relations between UCS performance of CTB and SD, c/t, and curing time (CT) were discussed while examining the microstructure of 28-day cured backfill with different solid contents. Results illustrate that a major increase in CTB viscosity by increasing the SD leads to the formation of tailings grains for a skeleton formation, which is formed due to consolidation and gravitational forces. The CTB’s strength increases with the increase of c/t, SD, and CT, due to a decrease in water-to-cement ratio and porosity, and an increase in hydration products over time. The SEM micrographs show how CTB’s microstructure is affected by the SD, generating ettringites and calcium silicate hydrates in the backfill matrix. The findings of this study will lead to an efficient CTB mix design for reaching the higher performance in underground mining structures, thereby reducing expenses related to the backfill.

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Rational Utilization of Fine Unclassified Tailings and Activated Blast Furnace Slag with High Calcium

Cited by 13 publications

References 36 publications

Compressive Strength Characteristics of Cemented Tailings Backfill with Alkali-Activated Slag

Compressive Strength Characteristics of Cemented Tailings Backfill with Alkali-Activated Slag

Cost-Effective Treatment of Hemihydrate Phosphogypsum and Phosphorous Slag as Cemented Paste Backfill Material for Underground Mine

Evaluation of Viscosity, Strength and Microstructural Properties of Cemented Tailings Backfill

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