Abstract

S. Raharjo¹, S. Muryanto², J. Jamari³ and A. P.Bayuseno^3,*

DOI : http://dx.doi.org/10.13005/ojc/320637

This paper presents results of investigation of scaling of calcium sulfate (CaSO₄) on metallic pipes. In this study, the optimizing variables; namely temperature (50-60⁰C), concentration of Ca²⁺ (2000-3000 ppm), citric acid concentration (10-20 ppm) were set-up to provide the optimum yield of the mass scales. The mineral scale detected using XRD is mainly gypsum, and the scale has a plate like morphology under SEM examination. SRM (surface response methodology) prediction provided that the temperature is a significant factor, while the Ca²⁺ concentration and the citrate are insignificant variables determining the optimal condition of the mass scale yields. An optimized mass scale response of 119.99 mg was obtained at a temperature of 56.36 ^OC, concentration Ca²⁺ of 2649.21 ppm and citric acid concentration of 12.11 ppm, respectively. The addition of citric acid did not modify the crystal morphology, but may control the size of crystals.

Calcium sulfate; Surface response methodology (SRM); XRD/SEM analysis; Gypsum

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