To meet the global challenge of declining ore grades and increasing price of energy a novel hydrostatic pressure reactor for the metals processing industry have been developed. The new type of reactor is energy efficient and can utilize low-grade raw materials that are currently not economically feasible.


At Outotec, a revolutionary new type of reactor for the metals processing industry was developed for utilising low-grade raw materials that are currently not economically feasible. A novel tower-like reactor utilizes hydrostatic pressure offering high volume of effective fluid volume and very low energy consumption of mixing compared to conventional solutions. In addition, metallurgical performance, evaluated through calculations and experimental tests in pilot scale, is better compared to conventional solutions.

Test reactor

The studied equipment construction design was a hybrid concrete/fibre-reinforcement plastics structure. The support of FIMECC LIGHT programme was essential in structure and material design of the hydrostatic pressure reactor. The reactor is exposed to harsh conditions, such as erosion and corrosion from inside and external loads (e.g. wind loads, snow loads) from outside. In addition the combined effect of sulfuric acid environment, temperature and stress can cause strength loss in building materials. The reactor’s construction methods and materials were investigated in co-operation with Aalto University. The relevant properties, such as long-term strength of fibre-reinforcement plastic materials and wear resistance, were thoroughly investigated by Aalto University and by Tampere University of Technology. The multidisciplinary development approach enabled the acquisition of a sound basis for the techno-economical evaluation of the novel reactor concept.


Declining ore grades and increasing price of energy are global megatrends in metallurgical industry. These global megatrends set new requirements for process equipment in terms of size and energy efficiency. Atmospheric reactor size, however, cannot be feasibly increased infinitely with the conventional design. Efficient gas dispersion requires sufficient mixing power intensity. With conventional design mechanical loads of agitator, tip speed of impeller blade, mixer motor and gear all increase along with reactor size, which causes severe wear issues. Thus there is a growing need for novel solutions in the field of hydrometallurgical equipment. The hydrostatic pressure reactor is one revolutionary idea for the future.


Long-term research activities enabled the development, testing and validation of revolutionary ideas regarding to hydrostatic pressure reactor. In the metallurgical industry time span from idea to completely new process is long. Some ideas are and will be incorporated into existing products to provide faster time-to-market. In addition, scientific approach allowed to gather high-quality data that can be utilized in future product development.


Mari Lindgren, Outotec


Outotec, Tampere University of Technology, Aalto University