A large volume of waste mercury chloride catalyst (HgCl2) is generated by calcium carbide-based polyvinyl chloride production in China, which accounts for 30% of global mercury consumption. However, there are few studies on the leaching behavior and risk control of waste catalyst where mercury is in the form of HgCl2, which is more soluble than metal mercury and poses great threat to human heal...

In this paper, gold leaching of a refractory sulfide concentrate by chloride–hypochlorite solution was investigated and effects of stirring speed, temperature and particle size on the leaching rate were reported. Experimental data for leaching rate of gold were analyzed with the shrinking–core model. Results were consistent with chemical reaction control mechanism in the first 1 h of leachin...

Accumulation of beef cattle manure on feedlot pen surfaces generates large amounts of dissolved solutes that can be mobilized by water fluxes, affecting surface and groundwater quality. Our objective was to examine the long-term impacts of a beef cattle feeding operation on water fluxes and manure leaching in feedlot pens located on sandy loam soils of the subhumid Sandy Pampa region in Argenti...

After the demolition of concrete structures, it is expected to recycle the whole of the demolished concrete. As of now, however, it is difficult to recycle the fine powders generated in the processes of demolition of concrete and manufacture of recycled aggregate because these powders may contain heavy metals exceeding the soil environmental standard, and such powders are disposed finally. It i...

In this study, the treatment of fly ash and steel making slag in aqueous ammonia chloride has been conducted. These zero-value wastes have distinctively high concentrations of magnesium, calcium and iron. The ammonium chloride has been employed as the leaching reagent to extract MgO out of fly ash and slag, and the dissolved cations in the leachate were subsequently precipitated by carbonation....

titanium dioxide is widely used in the manufacturing of paints, varnishes, lacquer, paper, paperboard, printing inks, rubber, floor covering, and ceramics and so on. white titanium dioxide pigment has been produced by two main processes. the sulfate and the chloride processes. each of these two routes requires different feedstocks. however, economic and environmental pressures are shifting the ...

In water distribution systems containing PVC pipe manufactured in the ‘‘early era’’ ~prior to 1977!, vinyl chloride can leach into drinking water resulting in vinyl chloride concentrations exceeding the 2 mg•L maximum contaminant level. Field testing of dead-end segments of water distribution systems consisting of early-era PVC pipe was conducted to examine their initial intrapipe vinyl chlorid...

Portland cement (CEMI) was used to solidify air pollution control (APC) residues from an energy-from-waste plant burning municipal solid waste. APC residue/CEMI mixes were prepared with CEMI additions ranging from 0 to 50 weight% (wt%) of total dry mass and water/solids ratios between 0.40 and 0.80. Isothermal conduction calorimetry was used to assess the effect of APC residues on the hydration...

The recycling of platinum-group metals from wastes such as autocatalytic converters is getting growing attention due to the scarcity of these precious metals and the market pressure originated by increase of demand in current and emerging applications. Hydrometallurgical treatment of such wastes is an alternative way to the most usual pyrometallurgical processes based on smelter operations. Thi...