Abstract: The present invention relates to a method for continuously preparing mineral particles by means of the thermolysis of mineral precursors in an aqueous medium, comprising contacting: a reactive flow, including mineral precursors at a temperature lower than the conversion temperature thereof; and a coolant flow that is countercurrent to said reactive flow and contains water at a temperature that is sufficient to bring the precursors to a temperature higher than the conversion temperature thereof, the mixture flow that results from said reactive flow and said coolant flow then being conveyed into a tubular reactor, inside of which particles are formed by gradually converting the precursors, and where the reactive flow and the coolant flow are placed in contact with each other inside a mixing chamber, inside of which the reactive flow and the coolant flow are fed by supply pipes having outlet cross-sections that are smaller than the maximum cross-section of said mixing chamber.