Carbon-in-column

The ability of activated carbon to absorb gold and silver from solution has been commercially exploited since the beginning of the 1970s [46,47] and the techniques used can be classified in (i) carbon in pulp (CIP) (ii) carbon in leach (CIL) and (iii) carbon in column (CIC) [46,47]. 

The dark-colored clarified liquor is presure-filtered and concentrated to 60 percent solids in multiple-effect evaporators. The concentrated liquor is decolorized with granular carbon in columns 12 ft in diameter and 30 ft high in a countercurrent manner that is, liquor flows upward in the columns, while a portion of the carbon is removed from the bottom periodically. Carbon is used at a rate of 2.5 percent of dry solid processed, and approximately 5 percent of carbon is lost during revivification.91 In some cases, granular carbon has been replaced by synthetic polymeric adsorbents to decolorize the syrup. Low ash syrups usually are deionized with ion-exchange resins. The processed liquor is evaporated to a final solids content of 75-85 percent in a single-effect evaporator. 

CIC [Carbon In Column] A general name for hydrometallurgical extraction processes using activated carbon as the adsorbent, contained in a series of cylindrical tanks. 

Yq = adsorption capacity at breakthrough, lb adsorbate/lb adsorbent me = mass of carbon in column, lb... 

The table below provides information about azeotropes for 808 selected binary systems. Compounds are listed in the modified HUl order, with carbon-containing compounds following those compounds not containing carbon. In columns 1 and 2 are the molecular formulas of components 1 and 2 written in the HiU convention. In column 3 the names of the components are given, either a systematic lUPAC name or a name in ubiquitous use. Columns 4, 5, and 6 contain the azeotropic coordinates of the mixtures temperature T az, pressure Paz< and vapor-phase composition The explanation of the type of azeotrope (column 7) is given by the following codes ... 

M% apprHinatthr, second sugar char liquor, pH 4-S (under surface of carbon in column) Sugar F 70 42 - XX 0.0002bd <0.0001 ... 

The factor represents the fraction by weight of the element sought (Column i) in the final compound weighed (Column 2), e.g., the weight of carbon in x g. of carbon dioxide is therefore 0 2y2yx g. 

The carbon monoxide product is removed from the top of the column and warmed against recycled high pressure product. The warm low pressure stream is compressed, and the bulk of it is recycled to the system for process use as a reboder medium and as the reflux to the carbon monoxide column the balance is removed as product. The main impurity in the stream is nitrogen from the feed gas. Carbon monoxide purities of 99.8% are commonly obtained from nitrogen-free feedstocks. 

Adsorption. Adsorption (qv) is an effective means of lowering the concentration of dissolved organics in effluent. Activated carbon is the most widely used and effective adsorbent for dyes (4) and, it has been extensively studied in the waste treatment of the different classes of dyes, ie, acid, direct, basic, reactive, disperse, etc (5—22). Commercial activated carbon can be prepared from lignite and bituminous coal, wood, pulp mill residue, coconut shell, and blood and have a surface area ranging from 500—1400 m /g (23). The feasibiUty of adsorption on carbon for the removal of dissolved organic pollutants has been demonstrated by adsorption isotherms (24) (see Carbon, activated carbon). Several pilot-plant and commercial-scale systems using activated carbon adsorption columns have been developed (25—27). 

Many operating data for carbonate plants are cited by Kohl and Riesenfeld (Gn.s Purification, Gulf, 1985) but not including tower heights. Pilot plant tests, however, are reported on 0.10- and 0.15-m (4- and 6-in) columns packed to depths of 9.14 m (30 ft) of Raschig rings hy Benson et al. (Chem. Eng. Prog., 50, 356 [1954]). 

Graded Adsorbents and Solvents. Materials used in columns for adsorption chromatography are grouped in Table 12 in an approximate order of effectiveness. Other adsorbents sometimes used include barium carbonate, calcium sulfate, calcium phosphate, charcoal (usually mixed with Kieselguhr or other form of diatomaceous earth, for example, the filter aid Celite) and cellulose. The alumina can be prepared in several grades of activity (see below). 

Tsutsumi, A., Nieh, J.Y. and Fan, L.S., 1991. Role of the bubble wake in fine particle production of calcium carbonate in bubble column systems. Industrial and Engineering Chemistry Research, 30, 2328-2333. 

A solution of 100 g of sodium bisulfite in 200 ml of water is added, and the stirring is continued for 10 hours with exclusion of air. A thick precipitate separates after a few minutes. The bisulfite compound is collected by suction filtration, washed with ether until colorless, and then decomposed in a flask with a lukewarm solution of 125 g of sodium carbonate in 150 ml of water. The ketone layer is separated, and the aqueous layer is extracted four times with 30-ml portions of ether. The combined organic layers are dried over anhydrous magnesium sulfate, the ether is removed at atmospheric pressure, and the residual oil is fractionated under reduced pressure through a short column. The cycloheptanone, bp 64-65°/ 2 mm, is obtained in about 40% yield. 

Various wastes available as carbon substrates for SCP productions are listed in column A. Match each waste with a suitable organism (perhaps more than one) from column B. For each organism select the most appropriate production system from column C. 

Ref 28) and by the passage of Me chloride into hot aq Na nitrite and Na carbonate in an efficient column, yield 60% (Ref 28), Comm NMe was purified for conductivity and other measurements by the following procedure The NMe was distd, dried over anhyd Ca chloride, and redistd. During the final distn the distillate was passed thru a conductivity cell and the fractions with the lowest conductivity saved. 

Glaser and Lichtenstein (G3) measured the liquid residence-time distribution for cocurrent downward flow of gas and liquid in columns of -in., 2-in., and 1-ft diameter packed with porous or nonporous -pg-in. or -in. cylindrical packings. The fluid media were an aqueous calcium chloride solution and air in one series of experiments and kerosene and hydrogen in another. Pulses of radioactive tracer (carbon-12, phosphorous-32, or rubi-dium-86) were injected outside the column, and the effluent concentration measured by Geiger counter. Axial dispersion was characterized by variability (defined as the standard deviation of residence time divided by the average residence time), and corrections for end effects were included in the analysis. The experiments indicate no effect of bed diameter upon variability. For a packed bed of porous particles, variability was found to consist of three components (1) Variability due to bulk flow through the bed... 

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