Wet sieving method

Wet sieving method of sieving coal that uses water as a medium for facilitating segregation of a sample into particle size (ASTM D-4749). 

Wet sieving is recommended whenever it is possible. Instructions for sampling with wet sieving method are presented in section 3.2.3.1. If it is not possible to wet sieve the stream sediment sample in the field, the collected stream sediment material should be dry sieved. Instructions for sampling and dry sieving are given in section 3.2.3.2. 

The third shortcoming centers around the need for a good method for the determination of stable aggregates. The wet-sieve method, now commonly used, is generally recognized to be far from satisfactory. This is illustrated by the experiments of Harris et al. (1963), discussed below and shown in Fig.16.1. If a method had been used that measured true stable aggregates, as occur in nature, the values obtained would doubtless have been zero, or near zero, instead of values ranging up to 100%.. 

Duj effective opening size which corresponds to the sand diameter of the fraction of which 10%, determined by the wet sieve method, passes through the geotextile. 

In order to limit particle breakage and aggregations during sieving the use of the wet sieving method as deseribed in the BS 1377, Part 2 is recommended. 

Particle Size. Wet sieve analyses are commonly used in the 20 )J.m (using microsieves) to 150 )J.m size range. Sizes in the 1—10 )J.m range are analyzed by light-transmission Hquid-phase sedimentation, laser beam diffraction, or potentiometric variation methods. Electron microscopy is the only rehable procedure for characterizing submicrometer particles. Scanning electron microscopy is useful for characterizing particle shape, and the relation of particle shape to slurry stabiUty. 

Soil samples were wet sieved into (a) 2-4 mm, (b) 1-2 mm, (c) 0.5-1 mm, (d) 250-500 i m, (e) 125-250 am, (f) 63-125 j,m and (g) <63 j.m fractions. A ferruginous/magnetic fraction (m) was also prepared from the 2-4 mm fraction. Soil fractions were crushed, digested with HNO3/HCI/HF/HCIO4 and then analysed by Inductively Coupled Plasma Optical Emission Spectrometry (ICP-OES) for Al, Ca, Cu, Fe, K, Mn, Na, P, S and Zn. Inductively Coupled Plasma Mass Spectrometry (ICP-MS) was used to determine Ag, As, Cd, Pb and Sb because of the lower detection limits by this method. The mineralogy of selected samples was determined by qualitative X-ray diffractometry. 

Wet Sieving by a Mechanical Flushing Procedure. The sieve residue is the portion of coarse particles that cannot be washed through a specified test sieve with water. The result depends on the mesh size of the sieve. For standards, see Table 1 ( Residue on sieve Mechanical method ). Apparatus Mocker s apparatus. 

Dry sieveing is an alternative method if wet sieving (Section 3.2.3.1) cannot be used, as is the case of seasonal streams in Mediterranean countries. 

The procedure for the selection of sample sites, recording their location on the field map, completion of field observation sheets, wearing of rubber gloves, etc. are the same as for the wet sieving sampling method (refer to Section 3.2.3.1). 

Percent chrysotile asbestos in bulk samples may be measured by X-ray powder diffraction (NIOSH Method 9000, 1984) sample dust grinded under liquid N2 wet sieved through 10-mm sieve sieved material treated with 2-propanol agitated in an ultrasonic bath filtered on a silver filter measured by XRD, using a Cu target X-ray tube. 

Several manual methods of wet sieving using micromesh sieves have been described. Mullion [84] uses an 80 kHz, 40 W ultrasonic bath in which the micromesh sieve rests on a support, which, in turn, rests on a beaker in the bath. Sieving intervals are 5 min. with an initial load of 1 g. and the operation is deemed complete when no further powder can be seen passing through the sieve. 

Several writers have proposed automated wet sieving procedures [92,93]. In most of these methods, a stack of sieves is filled with a liquid and the... 

ASTM C285-88 (Re-approved 1994) Standard test method for sieve analysis of wet milled and dry milled porcelain enamel, for determination of the fineness of frit in wet-or dry-milled porcelain enamels and other ceramic coatings on metals by use of the number 200 or No 325 mesh, 212 ASTM C925-79 (Re-approved 1995) Standard test method for precision electroformed wet sieve analysis of non-plastic ceramic powders, for particle size distribution determination ofpulverized alumina and quartz for particle sizes from 45 pm to 5 pm by wet sieving, 212, 230... 

The different methods of particle size analysis can be grouped into several categories size range analyses (sieve methods), wet or dry methods, and manual or automatic methods (laser-light). All these methods are described elsewhere. 

There are many methods for the desulfurization of nature gas, which can be classified into dry desulfurization, wet desulfurization, and catalytic adsorption. In the dry desulfurization, some solid sorbents, such as iron oxide, zinc oxide, activated carbon (AC), zeolites, and molecular sieves, are used. In wet desulfurization method, liquid-phase chemical/physical solvent absorption systems are usually used for scrubbing H2S amine-based processes are subject to equipment corrosion, foaming, amine-solution degradation, and evaporation, and require extensive wastewater treatment. As a result, this sulfur removal technology is complex and capital intensive,44 although the processes are still employed widely in the industry. The desulfurization of coal gasification gas will be reviewed in detail in Section 5.5. In the catalytic-adsorption method, the sulfur compounds are transformed into H2S by catalytic HDS or into elemental sulfur or SOx by selective catalytic oxidation (SCO), and then, the reformed H2S and SOx are removed by the subsequent adsorption. 

Y = percent of soil particles <0.25 mm in diameter obtained by wet sieve aggregate analysis method. 

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