EXTRACTION AND LEACHING

Ruth, B. F. Chem. Eng. Prog. 44 (1948) 71. Semigraphical methods of solving leaching and extraction problems. 

In the latter case, it is advisable to use reference materials, if available, because the addition of an internal standard carries a risk that the degree and manner of binding between the compound and matrix are not accurately reproduced, leading to an overestimation of recovery. In the former case, however, the procedure is simple and problem-free from the analytical point of view. Recovery can be assessed for both leaching and extraction. 

Leaching and Extraction of Mineral Values from High... 

Leaching and Extraction of Mineral Values from High Concentration of Solids A uranium plant had 10 large slurry tanks for leaching and extraction (approximately 14 m in diameter and 14 m high). They had about 14,000-m capacity. 

Leaching and extraction tests are used widely to assess trace element mobility and phytoavailability, as reviewed by Krishnamurti and Naidu hi Chapter 11. 

Leaching and extraction tests are widely used for assessing trace element mobility and phytoavailability. As measurements in these protocols are made in equilibrium conditions, only thermodynamic information is obtained. However, kinetic extraction—desorption studies are a more correct approximation to the distribution of species in natural media. The desorption rate constants of the trace elements in sediments and soils can be related to their mobility and toxicity. Detailed studies are needed in this area. 

Science of the Total Environment (1996) Special Issue on Leaching and Extraction Tests for Environmental Risk Assessment. Volume 178. 

The presence of CO2 influences the pH of an aqueous phase, due to formation mid dissociation of carbonic acid. The resulting pH is equal to values of about 2.9 at 200 bar and 40°C (9). The dissolution of metals in water determines die extent of leaching and extraction. To study the pH... 

The term spedation will be defined here both in an operational and in a more descriptive way (Bernhard et al. 1986). Operational means the use of appropriate analytical separation and detection methods (e.g. filtration, chemical leaching and extraction, chromatographic fractionation, atomic absorption) designed to simulate conditions, which may favor the "extractability" of a particular metal form, association, or binding substrate. 

The delivered packages of process chemicals have trended to larger sizes and recyclable containers due to purity, cost, and safety reasons. ] Typically, the most common recyclable containers have a capacity of 200 liters with the added advantage of improved purity after early uses because of leaching during the initial service.(Note In this chapter the terms leaching and extraction are used as synonyms. In the microelectronics industry, the term leaching is specific to extraction... 

Leaching and extraction tests are designed to reach one of three end points ... 

El-Nadi, Y. A., Daoud, J. A. Aly, H. F. (2005). Modified leaching and extraction of uranium from hydrous oxide cake of Egyptian monazite. International Journal of Mineral Processing, 76,1-2,101-110, ISSN 0301-7516... 

---