Optimization of dissolution of ulexite by pure CO2 gas in aqueous medium under pressure and production of sodium pentaborate

Abstract

The obtain of the boron compounds from Ulexite which is one of the most important ores of Turkey is important. In this study, optimization of dissolution of ulexite by pure CO₂ was investigated in aqueous media under pressure in according to Taguchi method. Temperature, particle size, solid-to-liquid ratio, reaction time and pressure were chosen as parameters for the studies carried out in a high pressure-high temperature reactor. After dissolution experiments, optimum conditions for the dissolution of ulexite were found as 75 g/300 g water (A₁) for solid-to-liquid ratio, 15 bar (B₃) for CO₂ pressure, 80 ℃ (C1) for temperature, 60 min (D₃) for time and -150µm (E₁) for particle size. The solutions obtained under optimum conditions were dried using a spray drier. Further, after the solution was concentrated, it was crystalized by cooling, and the crystals were filtered and dried. Chemical analyzes exhibited that the products obtained in both cases are sodium pentaborate (Na₂B₁₀O₁₆₎ with different water contents. 

Keywords

• Ulexite,carbon dioxide,sodium pentaborate,Taguchi method

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