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

Lijie Guo,Wenchen Li,Wenyuan Xu,Xiaocong Yang

doi:10.1155/2018/8502057

Abstract

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.

Highlights

It is known that cemented tailing backfill (CTB) technology is a common method for ground support and mine waste disposal during mining operations [1,2,3,4,5]
Active e ect of sodium silicate gel on cemented tailing back ll that contain lead-zinc smelting slag can be seen in the strength evolution of CTBs at early ages
It can be observed that the CTB, whose leadzinc smelting slag is activated by sodium silicate gel (SS), shows signi cantly higher 28 days UCS than CTB that does contain SS

Summary

Introduction

It is known that cemented tailing backfill (CTB) technology is a common method for ground support and mine waste disposal during mining operations [1,2,3,4,5]. CTB is a mixture of dewatered tailings, a hydraulic binder, and water [2, 3]. The dewatered tailing is accounted for a high proportion between 70% and 85%, and the hydraulic binder only occupies a small proportion between 3 and 7 wt.%. Ordinary Portland cement type I (PCI) is usually used as a binder in CTBs, and the binder consumption can account for up to 75% the cost of CTB [5]. Many previous studies [6, 7] try to reduce the cost as well as improve the properties (such as microstructure and strength) of CTB by a partial replacement of Portland cement by ground-granulated blast furnace slag (GGBFS), nonferrous smelting slag, or fly ash. Lead-zinc smelting slag is a low-cost by-product which can be a pozzolanic material and reacts with water and lime to produce cementitious products [8,9,10]

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Results

Conclusion