Employees are first to get it Take, for example, hydrofluoric acid, which is the chemical most frequently used in etching chips and which is known in environmentalist circles as "the bone dissolver." Most firms use the calcium ions in calcium carbonate or calcium chloride to neutralize the hydrofluoric acid in the water that was used to wash the chips. This creates calcium fluoride which precipitates out of the solution.
以業者最常用來蝕刻、被環保人士稱為化骨水的氫氟酸為例，廠商多半以石灰與氯化鈣中的鈣離子去中和含有氫氟酸的清洗廢水，產生氟化鈣沈澱物。