Production and characterization of synthetic aragonite prepared from dolomite by eco-friendly leaching–carbonation process

Abstract

Dolomite is an alternative material for producing precipitated calcium carbonate (PCC) particles, which have widespread industrial applications depending on their morphology and particle sizes. These properties are readily controlled by the production conditions such as reaction time, temperature, stirring speed, and CO2 flow rate. In this paper, we investigate the influences of these experimental conditions on the production of synthetic aragonite crystals from dolomite using a leaching carbonation process. The proposed process is believed so be more eco-friendly than other methods suggested in the literature because the CO2 released from the dolomite during the leaching stage is stored for use in the carbonation stage. The experimental results indicate that the morphology of the produced PCC is influenced not only by the reaction time and temperature, but also the stirring speed and CO2 flow rate. The required reaction time decreases with an increase in the CO2 flow rates. However, calcite forms along with the aragonite crystals at higher CO2 flow rates. We successfully synthesized pure aragonite crystals in the reaction temperature range of 40–70°C at a fixed CO2 flow rate of 3.00l/min, and at a stirring speed of 750rpm. The d90 values of the aragonite crystals at various temperatures ranged from 18.47 to 25.99μm. We fit the experimental results by a single-term exponential model.Additionally, we obtained a Mg-rich solution and CO2 gas as by-products, which are in high demand.