Leaching method

Batch leaching tests are designed to determine rates of desorption and equilibrium sorption relationships imder conditions of high mixing, high surface areas of the construction material, and continuous surface renewal [1-4,240- 

Batch - The short-term (24-hour) leaching test also is conducted to pro- 

Flat plate - The flat plate tests determine the leaching rates from a defined leaching surface where mass transfer across a solid/liquid boundary controls 

Column - The column experiment is used to simulate the reference environ-leaching ment where the crushed test material (by itself or mixed with an 

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Pressure-acid leaching was used to extract cobalt from Blackbird mine ores before its closing in 1974. The result was a very fine cobalt powder which was subjected to a seeding process to produce cobalt granules. Leaching methods are also used in the refinement of lateritic ores. 

The cylindrical porous scaffolds based on TMC-DLLA copolymers were prepared by salt-leaching method. Two-ply porous nerve guides were prepared by a combination of dip-coating (inner layer) and fiber-winding (outer layer) techniques. 

In later work, PEO and PCL PUs were blended by simple mixing to form three-dimensional sponges using solvent cast/particulate leaching methods. 

In the first test phase, several weak leach methods were tested. Samples were collected from the small hand-dug test pits... 

The test of weak leach methods shows that glacigenic till and stratified sediments are usable material for mobile metal ion tracing. The thickness of overburden is not an essential factor for affecting the mobile ion concentrations in the upper soil horizon. However, the influence of complex till stratigraphy is not clear for ion mobilization from the bedrock source of surface. 

Use of weak leach methods shows that mobile ion concentrations in the upper soil horizons can be used for tracing mineralization or mineralized structures in... 

See also Kinetic measurements first-order irreversible, 25 286-287 Chemical leaching methods, for graphite, 12 782-783... 

Similar applications have been described for catalysts containing aluminum-deficient Y zeolites prepared by the steam/EDTA-leaching method, e.g. (32). 

PHASE SEPARATION/LEACHING METHODS AND CLASS MEMBRANES... 

Porous glass membranes prepared by leaching methods can be obtained with pore size between 2 and 200 nm. The internal surface is active and can be... 

Name / location Leaching method Capacity (tons / year) Startup... 

The subsamples were split and sent to different laboratories to be subjected to ten commonly-used and proprietary leach/digestion techniques (a) aqua regia partial digestion method at Acme Analytical Laboratories (b) sodium pyrophosphate and cold hydroxylamine leaches at ALS Chemex (c) enzyme and TerraSol leach methods at Skyline Labs (d) Bioleach and soil gas hydrocarbon analyses at Activation Laboratories (e) Mobile metal ion (MMI) extraction at SGS Minerals (f) 4-acid near-total and sodium peroxide sinter total digestions (under the uses contract) at SGS Minerals and (g) de-ionized water leach at the USGS laboratories. 

Based on the results of this matrix evaluation, cold hydroxylamine leach and enzyme leach methods were chosen for use in subsequent field seasons. 

Fig. 3. Distribution of Mo in soil samples analyzed by the enzyme leach method.

Fig. 4a, b. Scanning electron photomicrographs of amorphous poly(L-lactic acid) foams a 92% porosity and 30 pm median pore diameter b and 91% porosity and 94 pm median pore diameter. Prepared by a solvent-casting and particulate-leaching method [32] using 90 wt% sieved sodium chloride particles of size range between 0-53 pm and 106-150 pm, respectively... 

Alkali leach methods axe exemplified by the Bayer process for the preparation of pure a-A C for electrolysis (Section 17.5) from the mineral bauxite. Bauxite consists mainly of a-AlO(OH) (diaspore) and/or 7-A10(0H) (boehmite), the difference between these being essentially that the oxygen atoms form hep and ccp arrays, respectively. The chief contaminants are silica, some clay minerals, and iron(III) oxides/hydroxides, which impart a red-brown color to the mineral. Aluminum (III) is much more soluble than iron(III) or aluminosilicates in alkali, so that it can be leached out with aqueous NaOH (initially 10-15 mol L 1) at 165 °C under approximately 0.6 MPa pressure, leaving a red mud of iron (and other transition metal) oxides/hydroxides and aluminosilicates ... 

Generally, the leaching rates of puddle glass determined by the one-pass dynamic leaching method decrease with time in a similar fashion to those determined on synthetic glasses using various static methods. 

Meguro,Y. Iso, S. Yoshida,Z. Tomioka, O. Enokida,Y. Yamamoto,I.Decontamination of uranium oxides from solid wastes by supercritical C02 fluid leaching method using HN03-TBP complex as a reactant, J. Supercrit. Fluids 31 (2004) 141-147. 

The significance of these two strontium nuclides warrants reliable procedures for their analysis. Leaching methods [ 11,12,18] for the determination of radiostrontium in soil are applied to large-size samples for higher sensitivity but they assume that the strontium can be easily solubilised. This assumption is not needed in the procedure described, since the sample is decomposed completely. Also, the procedure can be used to analyze leached residues to check the completeness, and thus the reliability, of leaching procedures when higher sensitivities are needed. 

While different kinds of leaching simulation tests (e.g., involving columns, lysimeters) have been described in the literature (Kylefors et al., 2003), WASTOXHAS leaching methods were selected in order to ... 

In the case of solid environmental materials such as soils, sediments or indeed suspended particulates the use of selective chemical leaching methods can provide some basic information regarding the nature of the radionuclide species bound to the solid matrix. A typical sequential leaching might follow a procedure similar to that suggested for the study of trace metal binding to sediments by Gupta and Chen (1975) as shown in Fig. 13.2. 

Muller, P.J., and Schneider, R. (1993) An automated leaching method for the determination of opal in sediments and particulate matter. Deep-Sea Res. 40, 425 144. 

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