Carbonate Solubility in Open and Closed Systems

Calcium Carbonate Solubility in Open and Closed Systems 

Many of the concepts presented in Chapter 5 and in the previous sections of this chapter can be incorporated into calculations concerning calcium carbonate, CaC03(s). Calcium ion forms weak soluble complexes with carbonates, such as CaC03 and CaHC03, and with hydroxides, such as CaOH+ as well as forming the sparingly soluble solid, CaCOsfs). 

Recht and M. Ghassemi, Kinetics and Mechanism of Precipitation and Nature of the Precipitate Obtained in Phosphate Removal from Wastewater Using Aluminum(III) and Iron(III) Salts, Report No. 17010EKI 04/70, U.S. Dept, of Interior, Federal Water Quality Adm., Cincinnati, 1970. 

Pure calcium carbonate exists in two distinct crystalline forms. These are the trigonal solid calcite which in its pure forms has a solubility product of 10 and the orthorhombic solid, aragonite, which in pure state has Kso = both at 25 C. When CaCOstsj precipitation takes place 

In this section we will consider various situations that involve equilibria with CaCOais). The following three cases can serve as models for the behavior of natural systems in which CaCOatsj participates. 

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