Contact cooling water

Homogenizing, annealing, and aging are dry processes whereas solution heat treatment typically involves significant quantities of contact cooling water. 

Contact cooling water is any wastewater that contacts the aluminum workpiece or the raw materials used in forming aluminum. 

Direct chill casting is the pouring of molten aluminum into a water-cooled mold. Contact cooling water is sprayed onto the aluminum as it is dropped into the mold, and the aluminum ingot falls into a water bath at the end of the casting process. 

Generally, water is used in this plant to cool, leach, filter wash, scrub, heat, and washdown. The unreacted ore is slurred and sent, along with chromium and other impurities originally present in the ore, to the treatment plant. The boiler blowdown, which is sometimes contaminated with chromium escaping from the process area, adds to the volume of wastewater coming from the plant. The non-contact cooling water from the plant contains dissolved sulfate, chloride, and chromate thus it is sent to a wastewater treatment plant. The scrubber water may be used to slurry the ore or discharged. 

Cooling water constitutes a major portion of the total in-plant wastes in fertilizer manufacturing and it includes water coming into direct contact with the gases processed (largest percentage) and water that has no such contact. The latter stream can be readily used in a closed-cycle system, but sometimes the direct contact cooling water is also recycled (after treatment to... 

NATIONAL (cont.) solution heat treatment contact cooling water 13.10 6.518 ... 

The formula mixture is finally forced (extruded) through a set of dies where it is drawn into long, thin strands.These strands are pulled through contact cooling water for a few seconds, which causes the resin to set before it enters a pelletizer. The pelletizer is a sharp fan or chopper that rotates at a specific speed coordinated with the strand feed rate to slice the strands into pellets of the desired size. The pellets are then automatically screened, and pellet product of the correct specification size range is dropped into the desired packing container. Rejected pellets and particle product are returned as feedstock to the front of the extrusion process for reprocessing. 

The sulfuric acid used to dry the chlorine is also sometimes a source of ammonia compounds. Finally, the plant utilities are likely sources. Plant water that has not been thoroughly purified has many opportunities to enter the process. Examples of these opportunities are the use of impure water to prepare treatment chemical solutions, flushing water on rotating machinery seals, water recycle from waste-minimization systems, and direct-contact cooling water. Steam and its condensate are also potential sources. The culprits here usually are the amines used as corrosion inhibitors in the steam system (Section 12.3.2). 

Uses Scale Inhibitor for boiler water (food contact), cooling water, pulp/paper processing dispersant for calcium carbonate, preventing scale buildup food-contact paper/paperboard... 

Uses Scale inhibitor and dispersant for water treatment, boiler water (food contact), cooling water, pulp/papermaking systems food-contact paper/paperboard Features Resist, to chlorine and compat. with most microbiological control agents Regulatory FDA 21CFR 173.310,176.170,176.180 Properties Cl. to si. hazy liq. m.w. 3300-3900 sp.gr. 1.20-1.25 dens. 10.0-10.4 lb/ gal vise. 500-2000 cps pH 3.0-3.5... 

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