A vortex chamber device comprising: a reactor comprising at least one chamber having a substantially circular cross-section; a device for feeding at least one fluid that is gaseous or liquid into the chamber; a device for removing said one or more fluids from the chamber; a device for feeding powder particles or a powder particles precursor to said chamber; wherein said fluid removing device comprises at least one discharge opening for removing said at least one fluid from the chamber. The invention also provides a method for treating powder particles or a powder particles precursor.