Model leach process

Meima, J. A. 1997. Geochemical Modelling and Identification of Leaching Processes in MSWI Bottom Ash. PhD dissertation, Utrecht University, Utrecht, The Netherlands. 

The aim of this chapter is to present a conceptual model of the leaching process in landfills based on two exemplary field studies at a municipal solid waste incinerator (MSWI) bottom ash landfill, Landfill Lostorf, and a lysimeter investigation, Landfill Teuftal, containing cement-stabilized MSWI air pollution control (APC) residues. 

The recoveries of several rare earth elements in leachates obtained from apatite concentrates were determined by Jorjani et al. [68] for ICP-AES and ICP-MS. A neural network model was used to predict the effects of operational variables on the La, Ce, Y and Nd recoveries in the leaching process. The neural network employed was a feed-forward one. 

Wagenet, R.J. and J.L. Hutson (1989). LEACHM Leaching estimation model - a process based model for water and soute movement, transformation, plant uptake and chemical reactions in the unsaturated zone. Continuum Vol. 2. Water Resources Institute, Cornell University Ithaca, NY. 

Chemical processes involving multicomponent multistage leaching were modeled in the following way depending on the process type and complexity ... 

Aquifers with double porosity (e.g. sandstones with fractures and pore volume) require special considerations with regard to transport modeling even if no reactive mass transport in its proper sense is taken into account. This problem is demonstrated with the following example of an aquifer regeneration in an uranium mine. The ore was leached in this mine by in-situ leaching (ISL) using sulfuric acid. The hydrochemical composition of the water that is in the aquifer after this in-situ leaching process is shown as ISL in Table 40 ... 

In order to be truly predictive, models for the complex leaching process must contain equilibrium, kinetic, and chromatographic parameters. Development of such comprehensive models will not only aid in the optimization of solution compositions for the most effective uranium recovery, but will also allow a more realistic environmental impact assessment. 

A model for the nano-structural evolution of Raney-type nickel catalysts (widely used in hydrogenation reactions) from the constituent intermetallic phases present in nickel-aluminium precursor alloys is presented here. Nano-porous nickel catalysts are prepared via a caustic leaching process where the NiAl alloy powder (typically 50-50 at.%) is immersed in concentrated NaOH solution in order to leach away the aluminium present to leave a highly-porous nickel catalyst (often referred to as spongy nickel). 

L, M, Calhles and J. A. Apps. A Model of the Dump Leaching Process that Incorporates Oxygen... 

M. Desai and H. Schwaitzberg, Mathematical Modelling in Leaching Processes, in Linko et al. 

The solubility of methyl parathion is not sufficient to pose a problem in runoff water as determined by an empirical model of Wauchope and Leonard (1980). Some recent monitoring data, however, indicate that methyl parathion has been detected in surface waters (Senseman et al. 1997). In a study to determine the residue levels of pesticides in shallow groundwater of the United States, water samples from 1,012 wells and 22 springs were analyzed for methyl parathion. No methyl parathion was detected in any of the water samples (Kolpin et al. 1998). In a study of water from near-surface aquifers in the Midwest, no methyl parathion was detected in any of the water samples from 94 wells that were analyzed for pesticide levels (Kolpin et al. 1995). Leaching to groundwater does not appear to be a significant fate process. 

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