Thermally induced changes in metalloid leachability of cemented paste backfill that contains blast furnace slag

2020 ◽  
Vol 156 ◽  
pp. 106520
Author(s):  
Andrew J. Bull ◽  
Mamadou Fall
Keyword(s):  
Blast Furnace ◽  
Blast Furnace Slag ◽  
Cemented Paste Backfill ◽  
Thermally Induced ◽  
Paste Backfill ◽  
Induced Changes ◽  
Furnace Slag

scholarly journals Substitution of Cement with Granulated Blast Furnace Slag in Cemented Paste Backfill: Evaluation of Technical and Chemical Properties

Minerals ◽  
2021 ◽  
Vol 11 (10) ◽  
pp. 1068
Author(s):  
Soili Solismaa ◽  
Akseli Torppa ◽  
Jukka Kuva ◽  
Pasi Heikkilä ◽  
Simo Hyvönen ◽  
...  
Keyword(s):  
Compressive Strength ◽  
Blast Furnace ◽  
Mine Tailings ◽  
Blast Furnace Slag ◽  
Partial Substitution ◽  
Cemented Paste Backfill ◽  
X Ray ◽  
Granulated Blast Furnace Slag ◽  
Paste Backfill ◽  
Furnace Slag

Cemented paste backfill (CPB) offers an environmentally sustainable way to utilize mine tailings, one of the largest waste streams in the world. CPB is a support and filler material used in underground mine cavities, which consists of mine tailings, water, and binder material that usually is cement. Replacing cement with secondary raw materials like granulated blast-furnace slag reduces the total CO2 emissions and strengthens the internal microstructure of the CPB. This study characterizes the total- and soluble contents of CPB starting materials and five CPB specimens containing different levels of slag substitution. In addition, phase composition (mineral liberation analysis, MLA) and internal structure (X-ray tomography) of five CPB specimens is documented, and measurements of compressive strength are used to evaluate their suitability as backfill material. Mine tailings and CPB specimens used in this study are rich in sulphates and arsenic, but low in sulphides. Stronger As leaching of ground CPB specimens compared with ground mine tailings is related to the elevating pore water pH during the cement hydration. The hydration product ettringite is found in all CPB specimens and its content is the lowest in the slag containing specimens. X-ray tomography revealed vertically differentiated density structures in the CPB specimens. The lower parts of all specimens are denser in comparison with the upper parts, which is probably due to the compaction of the solid particles at the base. The compressive strength test results indicate that partial substitution of cement with slag improves the strength of the CPB. The total replacement of cement with slag reduces the early strength but gives excellent strength and lower porosity over longer time intervals. The results of the study can be utilized in developing more durable and environmentally responsible CPB recipes for gold mines of similar mineral composition and gold extraction method.

scholarly journals Evaluation of Rheological Parameters of Slag-Based Paste Backfill with Superplasticizer

2021 ◽  
Vol 2021 ◽  
pp. 1-11
Author(s):  
Zhonghui Zhang ◽  
Yuanhui Li ◽  
Lei Ren ◽  
Zhenbang Guo ◽  
Haiqiang Jiang ◽  
...  
Keyword(s):  
Blast Furnace ◽  
Blast Furnace Slag ◽  
Low Cost ◽  
Solid Content ◽  
Binder Content ◽  
Rheological Parameters ◽  
Chemical Admixture ◽  
Shear Yield ◽  
Paste Backfill ◽  
Furnace Slag

The use of blast furnace slag-based binders in cemented paste backfill (CPB) has become increasingly popular in China, due to its low cost and superior early-age strength. Increasing the solid content can increase the strength of CPB, but it will lead to a decrease in its fluidity. As a chemical admixture that can improve CPB slurry fluidity, superplasticizer is gaining increased interest in the field of CPB. In this study, the effects of superplasticizer types and dosages, curing time, solid content, and binder content on the rheological properties of fresh CPB made of blast furnace slag-based binder (Slag-CPB) were studied. For Slag-CPB samples, polycarboxylate (PC) has the best water-reducing effect, followed by polymelamine sulfonate (PMS) and polynaphthalene sulfonate (PNS). In the absence of a superplasticizer, the shear yield stress and plastic viscosity of Slag-CPB are lower than those of CPB made of ordinary Portland cement (OPC-CPB). The water-reducing effect of PC on OPC-CPBs samples is stronger than that of Slag-CPB samples. The degradation rate of the water-reducing effect in slag-based samples is higher than that in cement-based samples. The effect of PC is affected by solid content and binder content. These results will contribute to a better understanding of the rheological behavior of Slag-CPB with superplasticizer.

Study on the Shrinkage of a Full-Scale Wall Made with Blast Furnace Slag Fine Aggregates

CONCREEP 10 ◽  
2015 ◽  
Author(s):  
Tomiyuki Kaneko ◽  
Keiichi Imamoto ◽  
Chizuru Kiyohara ◽  
Akio Tanaka ◽  
Ayuko Ishikawa
Keyword(s):  
Blast Furnace ◽  
Blast Furnace Slag ◽  
Full Scale ◽  
Fine Aggregates ◽  
Furnace Slag
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