Refining kettles

The pyrometaHurgical processes, ie, furnace-kettle refining, are based on (/) the higher oxidation potentials of the impurities such as antimony, arsenic, and tin, ia comparison to that of lead and (2) the formation of iasoluble iatermetaUic compounds by reaction of metallic reagents such as 2iac with the impurities, gold, silver and copper, and calcium and magnesium with bismuth (Fig. 12). 

The lead contains residual calcium and magnesium that must be removed by chlorination or treatment with caustic and niter. The molten lead is pumped or laundered to the casting kettles in which it is again treated with caustic and niter prior to mol ding, After a final drossing, the refined lead is cast into 45-kg pigs or 1- and 2-t blocks. 

Poling kettle, in tin refining, 24 788 Polioencephalomalacia, 10 867 Poliomyelitis vaccine, 5 345t 25 488 Polio virus, 22 10, 11 Polished metals, and object mode perceptions, 7 306t Pohshes, colloids, 7 273t Pohshing, of staple-fiber non woven fabrics, 27 515... 

Refining kettles S02, particulates Local exhaust system, cooling device, baghouse or precipitator... 

The flakes are heated to over 190°F (87.8°C) in the upper kettle. Flakes with high phosphatide content may benefit from being cooked at slightly lower temperatures to avoid elevating refining losses. The temperature of the flakes is raised to 230-270°F (110-132.2°C) in the lower kettles. The seeds are cooked for up to 120 minutes and, depending on the size of the cooker, 81-136 metric tons (90-150 short tons) of meats may be cooked in a 24-hour period. 

Fats and oils can be saponified via the full-boiled process. The saponification process can be briefly described as follows. A refined blend of fats and oils is charged into a kettle and a predetermined amount of soap lye with sufficient concentrations of caustic soda, and salt is added. The mixture is boiled vigorously, using closed steam coils, until saponihcation is almost complete. The amount of caustic soda added is deliberately made less than the stoichiometric requirement, to ensure that the spent soap lye containing the glycerine has minimum alkalinity. The caustic soda in the spent soap lye is neutralized during subsequent treatment of the latter. 

Secondary producers often employ the same kettles for alloy formation as are used in the refining process. This is because the equipment needed to alloy certain elements is common to both processes. High-speed stirring and correct fume... 

The electrolyte for the two electrodes in the PLACID electrolytic cell is dilferent and is separated by a membrane that is permeable only to protons (H" "). On the cathode, lead chloride is stripped of its lead atom to leave chloride ions which, in turn, combine with protons passing through the membrane from the anode to reproduce hydrochloric acid. The latter is returned to the leaching bath for re-use. The electrolysis deposits lead as dendrites (spongy form of lead). The dendrites are shaken off the cathode, collected, and removed from the bath on a semi-submersed conveyor belt. The dendrites are pressed to expel excess electrolyte, and form platelets of pure lead that can be melted in a conventional refining kettle and cast into ingots of 99.99% purity. 

With this method, the refining process takes place in open kettles, usually quite large, heated by a direct flame underneath. Plants producing lead from spent batteries prefer this process because the investment and direct costs are lower and there is a small quantity of secondary metals. Refining can be performed either continuously or in batches, according to the production requirement of the plant. 

The importance of S bonding has been discussed, and refined values of the spin-spin coupling constant have been given by Jotham and Kettle (374). Table LIV summarizes the available ESR data. An interesting molecule is cupric cyanoacetate, which forms a polymeric species... 

Refinery Betts Refinery Betts Refinery Pyrometillu ical Refining B Rdinery Kettle Decopperization... 

The refinery can process and cast three to five 250-ton kettles of lead per day. A typical analysis of the refined, but unalloyed (corroding grade), lead is given in Table m. The alloys produced in the refinery are typical of the alloys required in modem battery production and a wide variety of specialty lead products. 

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