To assess the chemical stability of sludges generated by neutralizing acid rock drainage (ARD) with alkaline reagents, synthetic ARD was treated with hydrated lime (batch and high-density sludge process), limestone, and two proprietary reagents (KB-1 and Bauxsol). The amorphous metal hydroxide sludge produced was leached using deionized water, U.S. EPA methods (toxicity characteristic leaching ...

Nutrient leaching in highly weathered tropical soils often poses a challenge for crop production. We investigated the effects of applying 20 t ha biochar (BC) to a Colombian savanna Oxisol on soil hydrology and nutrient leaching in field experiments. Measurements were made over the third and fourth years after a single BC application. Nutrient contents in the soil solution were measured under o...

The filter cake, generated from the cold-purification stage in a zinc electrowinning plant and considered as a hazardous waste containing heavy metals, was characterized for its chemical and mineralogical compositions by inductively couple plasma-optical emission spectroscopy (ICP-OES), X-rays diffractometry (XRD) and scanning electron microscopyenergy dispersive X-rays spectrometry (SEM-EDS). ...

an approach to recycle precious metals of cathode materials from spent lithium cobalt oxide batteries by using organic citric acid and hydrogen peroxide has been studied in this paper. the effects of molar ratio, solid-liquid ratio, reaction time and temperature on leaching efficiency of cobalt were investigated respectively. meanwhile the leaching kinetics equation of cobalt was established, a...

plant biomass harvested after heavy-metal phytoremediation must be considered as a hazardous waste that should be contained or treated appropriately before disposal or reuse. this study provides an evaluation of extractants for the removal of lead from abutilon theophrastus biomass. the research was carried out a leaching study to determine the lead-extraction efficiency of the different leacha...

The intensification of leaching of gold from a waste using mechanical activation (milling in water) and mechanochemical activation (milling in thiourea solution) were studied as the pretreatment steps. The leaching of “as-received“ sample in an acid thiourea solution resulted in 78 % Au dissolution, after mechanical activation 98 % and mechanochemical activation up to 99 % of the gold was leach...

Plant biomass harvested after heavy-metal phytoremediation must be considered as a hazardous waste that should be contained or treated appropriately before disposal or reuse. This study provides an evaluation of extractants for the removal of lead from Abutilon Theophrastus biomass. The research was carried out a leaching study to determine the lead-extraction efficiency of the different leacha...

The indium tin oxide scrap (ITOS) was mechanically activated by a stirring ball mill and subsequently studied for the leaching behavior and kinetics of extracting indium from ITOS in hydrochloric acid solution. The X-ray diffraction (XRD) analysis showed that MA caused the decrease in crystalline phase and increase in lattice distortion. The effects of reaction temperature and hydrochloric acid...

keep in mind the importance of cadmium, cobalt and nickel ions as environmentally and economically strategic heavy metals, the application of two acidic extractants, named bis(2-diethylhexyl)phosphoric acid (dehpa) and 2-thenoyltrifluoroacetone (htta), was assessed for the extraction-recovery of these ions from leached solution of spent rechargeable ni-cd batteries. the conditions for leaching ...