Abstract: The present invention describes a process for the treatment of a residual product for the production of a biochar, said process comprising: —providing a residual product material comprising at least phosphorous; said process also involving —performing a thermal treatment of the residual product material in a temperature of 800-1100° C. in at least a low oxygen containing environment, for the for the separation of volatiles in a stream also comprising at least cadmium (Cd), if present, and for the production of a nutrient-rich biochar comprising phosphorous.

Abstract: The present invention describes a process for the treatment of a precipitate starting material comprising magnesium ammonium phosphate, magnesium potassium phosphate or potassium phosphate, or any derivate thereof, or a mixture thereof, said process comprising dewatering of the precipitate starting material, wherein the dewatering is performed by use of a hydrocyclone followed by the removal of excess water by filtration, and wherein the product obtained is a powder product. Furthermore, the present invention also discloses a powder product comprising particles of magnesium ammonium phosphate and/or magnesium potassium phosphate, wherein at least 75% of the particles have a particle size of maximum 10 ?m and wherein at least 50% of the particles have a particle size in the range of 4-10 ?m.