A number of safety practices should be followed during alkaline precleaning and acid-pickling operations. Employees handling chemicals should wash their hands and faces, both before eating and before leaving at the end of a shift. Only authorized employees familiar with chemical handling safety rules should be permitted to add the chemicals to pickling tanks. Face shields, chemical safety goggles, rubber gloves, and rubber aprons should be worn by employees who clean or repair tanks or make additions of chemicals. Hard hats and safety shoes also should be worn. If splashed or spilled chemicals contact body parts, then employees should wash immediately and thoroughly with cool water and report promptly to an emergency facility for treatment. An emergency shower with quick-opening valves that stay open should be available, as should eye-wash fountains. Any changes in working procedures or any unusual occurrences relating to the use of chemicals should be brought to the attention of supervisory personnel.

Safe practices in the use of alkaline and acid solutions should be followed. Alkalis should be added to water slowly, using a hopper or shovel. Adequate agitation should be provided after an alkali has been added, to ensure that the chemicals dissolve. To prevent eruption of the solution caused by rapid dissolving of the alkali, the temperature of the solution should not exceed 66 °C (150 °F) during additions. Acids should always be added to water, rather than water added to concentrated acid. When preparing a new solution, acid should be added to cold water, and the solution should not be heated until the acid has been added. Additions of acid to hot pickling solutions should be made with extreme caution. Materials should be carefully immersed in and withdrawn from acid solutions to avoid splashing. Adequate ventilation also should be provided in the vicinity of a pickling operation.

Classification and Selection of Finishing Processes

K. Subramanian, World Grinding Technology Center, Norton Company

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