Slurry Filter Characterization

FIGURE 18.15 Test setup for CMP slurry handling and filter characterization. Experiments can be performed emplo5hng an air operated diaphragm (AOD) pump or a magnetically levitated centrifugal (MLC) pump. 

weight gain and ESEM, and electron dispersive spectra (EDS) for species detection, and (vi) filtration subsystem development and optimization. 

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Ultraviolet spectrophotometry (DuPont 400 SO2 analyzer) was used to monitor the gas phase SO2 concentrations and SO2 removal efficiencies. The pH of scrubbing liquor in each reactor was measured hourly during pilot testing. Solid dewatering properties were characterized by hold tank slurry settling rate and filter cake insoluble solids concentration. Detailed descriptions of the test facilities and analytical procedures were reported earlier(S). 

Solid [ -l,3bis(trimethylsilyl)cyclopentadienyl]lithium (LiCp", 7.26g, 33.6 mmol, prepared as in Section 33A) is added via an addition tube to a stirred, cooled (0°C) slurry of anhydrous thorium(IV) chloride (Cerac) (6.27 g, 16.8 mmol) in diethyl ether (250 mL). The mixture is stirred at 25 °C for 15 h. Volatile substances are removed at 25 °C and 10 torr. The resultant off-white foam is extracted into warm (50 °C) hexane ( 150mL), and the extract is filtered. The filtrate is concentrated (to 75 mL), then cooled to — 30°C to yield colorless crystals of [ThCp"2Cl2] (1). Yield 4.45 g (40%). A further crop of crystals is obtained from the mother liquor (total yield, 60%). For its characterization, see Table I. 

Unfortunately the use of such a relation other than illustrating first principles is extremely limited in industrial applications because both the specific area of the particles Sq and the porosity 8 are extremely difficult to characterize when dealing with agglomerated solids that are also compressible. A more useful analysis can be made to characterize the filterability of a slurry by the use of the filtration equation as defined by equation (2) below, that shows how the filtration rate is affected by the filter operating parameters (pressure drop AP, filtration area A, filter medium resistance and also slurry related parameters (viscosity p, solids concentration w, specific cake resistance rj ... 

Purification and Characterization, Purify the crude product by column chromatography. In a 1 X 10-cm buret, place 2.0 g of activated silica gel (100 mesh) packed wet (slurry) with methylene chloride ( ). Dissolve the product in about 1.0 mL of hexane and transfer the solution by Pasteur pipet to the column. Elute the material from the column using approximately 10 mL of 1 1 methylene chloride/hexane solvent. Collect the eluate in a tared 25-mL filter flask. 

Centrifugal filters are usually characterized as basket and screen centrifuges. All are capable of filtration, washing, and dewatering, in ttiat sequence. Table 3-11 shows ranges of application of centrifugal filters. The most important variables are the concentration of the feed slurry and the size range of the solid particles. 

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