Fill in for absent Operators and ensure safety guidelines are followed.
Controls premixer and reaction vessels to produce orthophosphate liquor by reaction of phosphoric acid with soda ash: Sets timing device on weigh tank to effect prescribed feed rate of soda ash to premixer. Starts premixer, pumps, exhaust fans, screw conveyors, and bucket elevator in required sequence. Observes flowmeters and turns valves to regulate flow of phosphoric acid and water to premixer as specified. Swings discharge spout over reaction vessel, and starts agitator in vessel to admit and mix product. Turns valve to regulate flow of steam through vessel heating coils to attain reaction, observing thermometer to verify required temperature. Lowers dipstick into tank to obtain sample for laboratory testing. Turns valves to add measured amounts of chemicals, as indicated by laboratory reports, to regulate chemical properties of mixture to specifications. Turns valves and starts pump to transfer finished mixture to spray drier feed tanks.