A gram of the substance is weighed into a porcelain crucible of 150 c.c. capacity, 50 c.c. of dilute nitric acid are added, and evaporated to dryness on the water bath. The nitric acid is removed with sulphuric acid. This treatment changes the lead sulphide that may be present to lead sulphate, which with the silica is removed by filtration.
Proceedings of the Iowa Academy of Science
©1909 Iowa Academy of Science, Inc.
"The Analysis of Smaltite with Special Reference to the Estimation of Arsenic and Cobalt,"
Proceedings of the Iowa Academy of Science, 16(1), 143-144.
Available at: https://scholarworks.uni.edu/pias/vol16/iss1/16