Artificial weathering pools of calcium-rich industrial waste for CO2 sequestration

Abstract

a b s t r a c tProcesses of carbonation of calcium-rich aqueous industrial wastes from acetylene production were performed mimicking rock weathering, using the atmospheric carbon dioxide as reactant. This residue was carbonated exposing it to the air in artificial pools with controlled solid-to-liquid and surface-tovolume ratios, and the efficiency of this simple mineral carbonation process was maximized. Considering realistic values of just one acetylene production plant, the intelligent handling of the calcium-rich waste would make it possible to counteract the emission of around 800 t of carbon dioxide per year, so the CO 2 emissions of the acetylene production could be completely compensated and its carbon footprint significantly reduced.X-ray diffraction patterns and thermogravimetric analyses reported the conversion, up to 88%, of the calcium hydroxide into calcium carbonate under atmospheric conditions. So, considering a realistic industrial scale-up, 476 kg of CO 2 could be captured with 1 t of dry waste. The morphology of the grains is resolved by electron microscopy, and can be described as needles 15 nm wide and 200 nm long arranged in grains smaller than 1 micron. We exploit these nanometric textural parameters (nanometric pores and particles having a specific surface area ∼50 m 2 /g) to design an efficient carbon fixation procedure. The aim of this work is to propose this simple carbonation technology, based on aqueous alkaline industrial waste, as a contribution to reducing global CO 2 emissions.

Technological Proposals for Recycling Industrial Wastes for Environmental Applications

“…This was estimated based on the hypothetical full efficiency of the carbon sequestration, according to the contents of the respective Ca and Na containing wastes (Table 2) and the density of the aluminum-rich liquid waste. This power is an interesting value if compared with other residues such as municipal solid waste bottom-ash (2.3%), carbon fly ash (2.6%), acetylene calcium-rich waste (7%) and paper mill waste (21%) [11].…”

“…This is because the dissolution of sodium sulphate and portlandite and the subsequent precipitation of gypsum are favored, instead of the precipitation of carbonated phases. The carbonation of this sample by weathering pools should consider longer times, together with rewetting the sample, as explained in [11]. Figure 5.…”

“…Firstly, simple weathering experiments where conducted in small scale "weathering pools" [11], that is, spreading the aqueous suspension on a flat surface for drying under room conditions and letting the sample react with atmospheric CO 2 . The carbonation of the solid phases occurred during drying under atmospheric conditions, typically taking from 3 days to one week.…”

Nonpolar Surface Modification Using Fatty Acids and Its Effect on Calcite from Mineral Carbonation of Desulfurized Gypsum

“…The CaCO 3 used in this study was in calcite form obtained from a gypsum carbonation plant established and operated by the Korea Institute of Geoscience and Mineral Resources (KIGAM, Daejeon, Korea) ( Figure 1). The CaCO 3 was used without a separate grading process because it comprised fine particles with a uniform particle size distribution [21]. The CaCO 3 samples obtained from the plant process were divided into samples that were unprocessed and atomized through a pulverization process, then naturally dried at room temperature or heat treated in an oven at 50-400 • C.…”

New method for carbon dioxide mineralization based on phosphogypsum and aluminium-rich industrial wastes resulting in valuable carbonated by-products

“…Two procedures were considered to evaluate the carbon capture efficiency of the new sequestration agent, PGA: (1) bubbling pure CO 2 into an aqueous suspension of the sequestration agent, and (2) using the "weathering pools" [25].…”