Gravimetric analysis precipitation process

One method for determining the amount of a given substance present in a solution is to form a precipitate that includes the substance. The precipitate is then filtered, dried, and weighed. This process, called gravimetric analysis, is illustrated in Example 4.9. 

Gravimetric analysis is one of the rhost accurate and precise methods of macro-quantitative analysis. In this process the analyte is selectively converted to an insoluble form. The separated precipitate is dried or ignited, possibly to another form, and is accurately weighed. From the weight of the precipitate and a knowledge of its chemical composition, we can calculate the weight of analyte in the desired form. 

Precipitation. Sulfate can be precipitated by either the barium or calcium ion, and both are used commercially. Turning first to barium, we note that the solubility of BaS04 is so low that its precipitation is the standard gravimetric technique for analysis for the sulfate ion. In a brine loop, the precipitation step could be located anywhere, but it is most convenient to combine it with the precipitation of metals in the brine treatment tanks (Section 7.S.2.2) and not to add another step to the process. 

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