Silver continuous removal process

If the dissociation constant of the acid HA is very small, the anion A- will be removed from the solution to form the undissociated acid HA. Consequently more of the salt will pass into solution to replace the anions removed in this way, and this process will continue until equilibrium is established (i.e. until [M + ] x [A-] has become equal to the solubility product of MA) or, if sufficient hydrochloric acid is present, until the sparingly soluble salt has dissolved completely. Similar reasoning may be applied to salts of acids, such as phosphoric(V) acid (K1 = 7.5 x 10-3 mol L-1 K2 = 6.2 x 10-8 mol L-1 K3 = 5 x 10 13 mol L-1), oxalic acid (Kx = 5.9 x 10-2 mol L-K2 = 6.4 x 10-5molL-1), and arsenic)V) acid. Thus the solubility of, say, silver phosphate)V) in dilute nitric acid is due to the removal of the PO ion as... 

On the Continent, the process of refining is conducted without the use of a cupel, properly so called. No bone-ash is employed. The test, if it may be turned so, Is the bed of the furnace itself, which consists of a kind of marl, firmly beaten down into a circular cavity, sloping from the sides to the centre, and allowed to dry. The roof of the furnace, which consists of a flat dome of bricks, built in a strong circular hoop of bar-iron, is movable by means of a crane. Several tons of lead are introduced at once, and after the roof has been replaced, the blast is transmitted through one or more apertures in one side of the furnace the whole mass of motal is then worked off continuously, without any addition, till the lead is ontirely removed, and the alloy of gold and silver is left fine. 

Even for palladium, contact times of at least 1 h are needed for these reactions to proceed substantially to completion, and the dialkyl sulfide extraction process is operated in a batch, rather than continuous, mode to accommodate this requirement. Gold(III), unless removed previously, is also extracted by dialkyl sulfides in the form of the complex AuC13(R2S), and silver(I) can be extracted from nitrate solutions as the complex AgN03(R2S)2.228... 

The pig lead contains about 2 per cent, of silver, and there are three processes for its desilverization, the final stage of each being cupellation. In the almost obsolete PaUinson process the lead is melted and then allowed to crystallize. The first fractions consist of almost pure lead, and the crystals are removed by means of perforated ladles. The crystallization is continued until the residual lead contains about 1 per cent, of silver. In the Rozan process the molten metal is agitated by revolving paddles or jets of steam, and the concentration continued up to 2 per cent. In the Parke process the silver is extracted from the... 

This study is on the development of high-purity isobutane production from isobutane-enriched stream by gaseous adsorption technology. Isobutane purification from Ci mixture, in which not only isobutane, but also n-butane and several kinds of Ct olefins in small or in trace are involved, is very difficult by a traditional distillation method because of their close relative volatilities between constituting components. The continuous layered 3-bed process in which was comprised of six steps as follows pressurization-1 by the cocurrent effluent gas from the other bed, pressurization-2 by isobutane (noduct, adsorption, cocurrent depressurization, countercurrent blowdown, and low pressure purge by isobutane product, was applied. From the experiment, isobutane product with over 99.9% purity and with the trace levels of olefin components could be obtained at ambient temperature. Silver impregnated cliq prefers to CMS for the removal of Ci olefins... 

As previously pointed out a practical application has been found for isopropyl nitrate. It was originally bebeved 111") that the substance could only be made from iso-propyl iodide and silver nitrate. Direct nitration was found to yield mainly acetone due to the oxidation of the secondary alcoholic group. However a process of continuous nitration of iso-propyl alcohol in the presence of urea has been described by Imperial Chemical Industries patents [36]. isopropyl alcohol and urea were introduced into nitric acid (over 40% HNOj) at its boiling temperature and a current of air stirred and removed unstable products. According to Desscigne (118) the method gave ca. S0% yield. He used nitric acid of over 50% HNO3 at 108-1 lO C. 

Two different techniques for silver elec-trorefining are employed, the Mobius and Balbach-Thum cells. The main difference between them is that the electrodes are arranged vertically in the Mobius cell and horizontally in the Balbach-Thum cell (Fig. 22). In the Mobius cell cast, crude silver anodes are suspended in anode bags that collect anode slime. The spent anodes are replaced continuously by new anodes. The method uses stationary or rotating stainless steel cathodes. Deposited silver forms dendritic crystals on the cathode and these are removed manually or continuously by automatic scrapers. The Mobius electrolysis process is most suitable for crude silver containing >90% Ag. With high copper content, the electrolyte must be regenerated very often, and with... 

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