Preparation and Hydration Mechanism of Mine Cemented Paste Backfill Material for Secondary Smelting Water-Granulated Nickel Slag

Abstract

Using secondary smelting water-granulated nickel slag (SWNS) after iron extraction as the main raw material, made composite activator (flue gas desulphurization gypsum (FGDG) and carbide slag (CS) are the main activators, Na2SO4 and cement clinker (CC) are the auxiliary activators) with cementing agents (CA), and then made into mine cemented paste backfill (CPB) material with iron ore tailings (IOT). The factors affecting the mechanical properties such as the composition of raw materials and the amount of activator were studied by means of mechanical property test, X-ray diffraction (XRD) and scanning electron microscope (SEM), the ratio of CPB material was optimized, and the hydration mechanism of CPB material was analyzed. The results show that when the mass fraction of SWNS, FGDG, CS, Na2SO4 and CC in CA is 85%, 5%, 5%, 3% and 2%. The 28d flexural strength and compressive strength of CPB material of SWNS reach 1.99 MPa and 3.38 MPa, which meet the strength requirements of mine CPB material. The results of X-ray diffraction (XRD), scanning electron microscope (SEM) and hydration mechanism analysis showed that both vitreous and crystalline substances in, CA of SWNS could be hydrated, and the main hydration products were ettringite (AFt) and Ca 2+ , Mg 2+ containing hydrated aluminosilicate (C-M-S-H) gel.

Properties and microstructure of total tailings cemented paste backfill material containing mining and metallurgical solid waste

“…With the rapid growth of the world's demand for mineral resources, people's requirements for environmental mining protection are increasing day by day, and mining equipment and technical level and gelling agent technical level are greatly improved (Wang F et al, 2020). Cemented paste backfill material (CPBM) is becoming a modern technology with high efficiency, strength, and recovery (Ghirian and Fall, 2016;Deng et al, 2017).…”

Experimental Study on Lead-Smelting Slag as Paste Filling Cementing Material

“…The binder made by fly ash, lime, and desulfurization gypsum is much better to the traditional cementing materials; its filling body can meet the general requirement of mining production [26][27][28][29][30]. Under the action of a variety of activators, the water-quench secondary nickel slag eventually generates silicate hydrate gel material that plays a major role in the later strength of the filling body [31,32]. In terms of mechanical properties, researchers mixed tailings with a certain amount of fiber to effectively improve the strength of backfill and obtain the compressive fatigue and damage evolution law of backfill, which can provide important theoretical basis for preventing the blasting impact damage of backfill [33].…”