Determining the best conditions for acid leaching of dolomite

Abstract

Acid leaching of dolomite with sulfuric acid is a chemical process to obtain
magnesium sulfate, where the acid dissolves magnesium carbonate and can
precipitate calcium sulfate from calcium carbonate. Acid concentration, time,
temperature, and stirring speed are the key variables for the study of this
process. The objective of this work is to determine the optimal conditions for the
acid leaching of dolomite. A Plackett-Burman experimental design was applied
to identify the most influential variables, followed by a Box-Hunter design to find
the optimal reaction conditions. The model identified that time, stirring speed,
and the concentration-temperature-time interaction are the significant factors for
dolomite leaching, while sulfuric acid concentration and temperature can be
kept constant. The wide variation in magnesium concentration (780– 4 257
mg/L) confirms the sensitivity of the process. The model allows predicting and
optimizing the extraction, determining that the optimal conditions are 300 rpm
for 30 minutes with high acid concentration and temperature, thus maximizing
the yield.