Alkaline activation of cement pastes with desulfurization slag

Abstract

The capability to recycle waste materials, such as steel slag, has appealed to the construction industry, as the cement industry faces a major challenge to reduce carbon dioxide (CO 2 ) emissions into the atmosphere. This paper investigated the obtainment of cement pastes with Kanbara reactor desulfurization waste slag (KR slag) through alkaline activation using silicate and sodium hydroxide solutions. The mixtures were analyzed by X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), thermogravimetric analysis (TGA), differential scanning calorimetry (DSC), compressive strength, and physical property tests. The FTIR, XRD, and TGA results pointed to chemical activation, forming C-S-H and C-(A)-S-H gels. The formation of these compounds indicated the possibility of using KR slag in cementitious composites for civil construction.

Sedimentation and rheological behavior of reactive and non-reactive magnesium hydroxide pulps for industrial spray dryer processing

“…In the last few decades, the interest in magnesium hydroxide (HM), Mg(OH) 2 , has grown due to its use in several industrial processes, such as: alkali agent, adsorbent of heavy metals and organic contaminants in wastewater, and effluent treatments [1,2]; fire retardant in polymers and epoxy resins [3,4]; silica removal and desulfurization of environments [2,5]; bleach and preservative in the papermaking process [6]; fertilizer in the agricultural sector [7]; stabilizer for controlled release of biologically active proteins [8]; and precursor in the production of other magnesium compounds [9]. Caustic magnesia hydration is one of the most known and advantageous routes to obtain HM, especially in countries with natural magnesite ore reserves, such as China, Turkey, Russia, and Brazil, which are responsible for more than half of the world's magnesite mine production [10].…”