PHASE PHENOMENA IN CALCITE-SEAWATER SYSTEM 



193 



UNREACTED SOLUTION 



REACTED SOLUTION 

 HPMV 



DO 



GAUGE 



D 



HP 



RELIEF 



OUTLET 



REACTOR 



HAMILTON TWO-WAY VALVE 



HIGH-PRESSURE 

 METERING 

 VALVE (HPMV) 



^N 2 



C0 2 AND N 2 



-^DECOMPOSITION 

 FLASK 



-RGI 



FLOWMETER 



CHROMATRONIX 

 TEE 



SAMPLE 

 IN 



PRECISION 

 PUMP- 



s 



Fig. 1 Pressure system for calcite dissolution. 



than 0.5% per day, the calibration being against the flowmeter connected to the 

 manifold. 



Standard carbonate solutions were prepared by adding appropriate amounts 

 of K2CO3 to each of six vessels containing known amounts of C0 2 -free water. 

 The K 2 C0 3 concentrations were adjusted to span the expected total C0 2 values 

 for Sargasso Sea water. The carbonate standards were protected against 

 atmospheric C0 2 by fitting them with tubes filled with Ascarite. In use, the 

 standard solutions were pumped to the decomposition flask in the same manner 

 as the seawater. A linear relation was obtained between analyzer output in 

 counts per second and total C0 2 in the standards. Seawater or standard 

 solutions sent to the decomposition flask entered a solution with a pH of 

 approximately 0.4 and thus had all their carbonate-system components 

 converted to C0 2 . Liberated C0 2 was swept from this acidic solution by a 

 controlled flow of pure nitrogen entering the solution through a fritted tube. 

 The resultant mixture of nitrogen and C0 2 then flowed to the C0 2 analyzer 

 (Beekman Model 15) 



The experiments were designed to investigate the dissolution of nearly pure 

 calcite in seawater under pressures typical of the deep sea. Representative 

 seawater for these experiments was collected from 2000 m in the Sargasso Sea, 



