Quicklime and Calcium Sulfoaluminate Cement Used as Mineral Accelerators to Improve the Properties of Cemented Paste Backfill with a High Volume of Fly Ash

Abstract

In order to reduce the CO2 emission and cost of binders used in cemented paste backfill (CPB) technology, new blended binders with a large amount of fly ash (FA) were fabricated. Different doses of quicklime and calcium sulfoaluminate cement (CṠA) were used as mineral accelerators to improve the early workability of CPB. The effects of CṠA and quicklime on flowability, compressive strength, pore structure, hydration heat, and hydration evolution were investigated experimentally. The results showed that the addition of quicklime and CṠA reduced the spread diameter of the fresh backfill and improved the mechanical performance of the hardened CPB. With increasing quicklime and CṠA, the cumulative hydration heat of the blended binder distinctly increased in the first 6 h. CṠA improved the initial hydration by increasing the reactivity, and quicklime increased the hydration rate by activating FA. The blended binder (15% quicklime + 10% CṠA) with the lowest CO2 emission and cost had potential application in filling technology.

Use of Potabilized Water Sludge in the Production of Low-Energy Blended Calcium Sulfoaluminate Cements

“…Compared to the OPC manufacturing process, CSA cements exhibit the following environmentally friendly features: (I) reduced limestone requirement (usually <35%), and therefore less kiln thermal input and CO2 generation; (II) lower synthesis temperatures (about 150 °C-200 °C) and more friable clinkers (lower grinding energy required); (III) larger clinker dilution with additions of sulfate sources; (IV) greater use of industrial wastes, especially as kiln feed components [33][34][35][36][37][38][39][40]. To further decrease CO2 emissions, CSA cements can be blended with various SCMs and/or mineral additions [41][42][43][44][45][46][47][48][49][50][51][52][53][54][55][56][57][58][59][60].…”

The benefit of delithiated beta spodumene to reduce the carbon footprint of cemented paste backfill

“…It has dramatically increased over 2022, brought about by the global pandemic and its adverse impact on the supply chain Chen et al (2022). recently highlighted the need to investigate new materials and methods for CPB to address the rising cost of cement and, most importantly, reduce the carbon footprint of mining activities(Ding & Zhang 2020;Su et al 2019). The latter is particularly a significant objective for IGO.…”