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U.S. Department of Labor
Domeniu: Government; Labor
Number of terms: 77176
Number of blossaries: 0
Company Profile:
A professional who tends battery of tanks that precipitate aluminum hydroxide from rich liquor. Respnsibilities include: * Schedules filling, seeding, and emptying of precipitator tanks. * Opens feedline valves to fill tanks to designated levels with liquor and alumina seed slurry. * Adjusts valves to regulate rate of filling precipitators and to maintain specified level in green-liquor tanks. * Opens feedline valves to admit measured quantities of aluminum hydrate seed particles into precipitators. * Turns valves to agitate mixture with compressed air. * Turns valves to control flow of liquor to tanks of secondary thickness. * Weighs sample of mixture in flask on platform scale. * Reads charts and graphs to determine amount of slurry or liquor required to obtain specified consistency. * Signals bottom-precipitator operator to pump mixture from tanks. * Records sequence of operations on forms. * May lubricate valves and adjust packing glands to prevent leaks.
Industry:Professional careers
A professional who controls temperature, chemical composition, and level of cryolite baths in reduction pots to smelt aluminum oxide into aluminum. Respnsibilities include: * Breaks off sample piece of crust formed on bath surface, and grinds it into powder, using roll crusher. * Routes sample to laboratory for analysis. * Dips out sample of solution and pours it into containers, using ladle. * Drops chemicals into sample and notes resultant color. * Adds specified amounts of chemicals and alloys to bath, according to color shade of sample, to maintain solution at specified level and composition. * Measures current flow and voltage between electrical connections on pots, using meters, and computes voltage drop between connections. * Measures temperature of bath, heat exchangers, and heat-control pipes, using pyrometer, and turns rheostat to regulate temperature. * Verifies specified distance between electrodes, using measuring rod. * Measures depth of bath, and computes amount of aluminum available for tapping. * Records tests made, amount of chemicals and alloys added to bath, and amount of aluminum tapped from pots.
Industry:Professional careers
A professional who operates machines to recover cryolite from scrap potlining. Respnsibilities include: * Sets mill gauge to specified feed rate and adjusts air volume, according to screen analysis from laboratory. * Sets hearth rheostats and heat controller to specified temperature, and turns valves to adjust rate of flow of steam and oil to burners. * Starts system of conveyors, grinder, roaster, mixer equipment, cooling and exhaust fans, and burners. * Moves levers to regulate flow of materials, and adjusts valve to control volume of liquor. * Turns valve to drain spent liquor and lime hydrate to causticizer tanks. * Makes titration test, records results, and sends samples to laboratory. * Observes gauges, indicators, thermometers, and controls to ensure conformity to specifications.
Industry:Professional careers
A professional who operates battery of electrical precipitators to collect metallic dust particles from fumes of smelting ore. Respnsibilities include: * Observes ammeters and voltmeters and moves panel controls to regulate flow of electric current to precipitators according to type of ore being smelted, or according to amount of draft, moisture content of dust, and color of stack emission. * Switches off electric current. * Replaces broken wire in precipitators, using pliers. * May turn valves to spray acid and water into chambers to oxidize dust particles. * May pull levers to actuate airhammers that knock dust from electrodes.
Industry:Professional careers
A professional who operates battery of electrical precipitators to collect metallic dust particles from fumes of smelting ore. Respnsibilities include: * Observes ammeters and voltmeters and moves panel controls to regulate flow of electric current to precipitators according to type of ore being smelted, or according to amount of draft, moisture content of dust, and color of stack emission. * Switches off electric current. * Replaces broken wire in precipitators, using pliers. * May turn valves to spray acid and water into chambers to oxidize dust particles. * May pull levers to actuate airhammers that knock dust from electrodes.
Industry:Professional careers
A professional who tends equipment that removes reagent from molybdenum ore concentrate. Respnsibilities include: * Installs different-size orifices to regulate flow of solids and liquids into vats. * Adjusts steam valve to maintain concentrate at specified steaming point. * Draws sample to determine alkalinity of concentrate, using titration test. * Regulates flow of lime solution into vats according to alkalinity test readings to neutralize acids. * Weighs sample and compares it with standard chart to determine percentage of solids in concentrate. * Inserts airhose into vats to clear clogged outlets.
Industry:Professional careers
A professional who tends thickeners that separate waste solids from ore solutions or water, preparatory to recovery of metal or disposal of waste. Respnsibilities include: * Turns valves to regulate flow of mixture into thickeners. * Inserts indicator into mixture to measure sludge level. * Observes operation of equipment, overflow of concentrated metal solution, and flow of sludge from tank. * Breaks up sedimentation in troughs with wooden paddle. * Prepares sample of sludge for chemical analysis by weighing sample, adding acid to facilitate settling of solids, and reducing amount of sample to desired proportion in splitter. * May titrate sample and compare resultant color with standard chart to test overflow solution for metallic content. * May add chemicals to soften water in tanks. * May fill out forms for scale readings and details of malfunctions. * May be designated according to kind of materials separated as Red-Mud Thickener Operator * Tailing-Thickener Operator.
Industry:Professional careers
A professional who operates classifier units to separate coarse and fine precipitated alumina particles from liquor. Respnsibilities include: * Regulates valves on settling trays of hydroseparators to draw fine particles from top and coarse particles from bottom of trays. * Adjusts valves to wash liquor from coarse particles in classifier unit. * Pumps fine hydrate from underflow of tray thickeners to storage tank for use in precipitating more alumina, and pumps coarse particles to storage tanks to await further processing. * Lubricates valves and adjusts packing glands to prevent leaks. * May open and close valves and start and stop pumps to circulate cleaning solutions through process lines. * May keep log of operations.
Industry:Professional careers
A professional who tends dewatering machines that filter moist solid aluminum hydroxide from coarse slurry. Respnsibilities include: * Turns valves to regulate flow of slurry and wash water to dewaterers and to admit solids to kilns, according to temperature readings, alumina-quality reports, and discharge rates given by kiln operator. * Adjusts valves to maintain supply of water for vacuum pumps, wash water, and water-cooled bearings. * Regulates valves in cooperation with other operators to obtain balancing levels in filtrate tanks, hydrate storage tanks, and hydrate storage overflow tanks. * Lubricates valves and adjusts packing glands to prevent leaks. * Changes automatic recording charts in machines. * Records tank levels and density readings of hydrate in log. * May tend dust-recovery system.
Industry:Professional careers
A professional who tends dewatering machines that filter moist solid aluminum hydroxide from coarse slurry. Respnsibilities include: * Turns valves to regulate flow of slurry and wash water to dewaterers and to admit solids to kilns, according to temperature readings, alumina-quality reports, and discharge rates given by kiln operator. * Adjusts valves to maintain supply of water for vacuum pumps, wash water, and water-cooled bearings. * Regulates valves in cooperation with other operators to obtain balancing levels in filtrate tanks, hydrate storage tanks, and hydrate storage overflow tanks. * Lubricates valves and adjusts packing glands to prevent leaks. * Changes automatic recording charts in machines. * Records tank levels and density readings of hydrate in log. * May tend dust-recovery system.
Industry:Professional careers