Low-grade phosphate rock from Sra Ouertane (Tunisia) was beneficiated using a thermal treatment consisting of calcination, quenching, and disliming. Untreated phosphate rock samples (group 1), calcined phosphate rock samples (group 2), as well as calcined, quenched, and dislimed (group 3) phosphate rock samples, were investigated using inductively-coupled plasma atomic emission spectroscopy (ICP-AES), inductively-coupled plasma mass spectrometry (ICP-MS), thermogravimetric analysis (TGA), and X-ray powder diffraction (XRD). Besides, the particle size distribution of the aforementioned three groups was determined. The proposed thermal treatment successfully increased the P₂O₅ content of the untreated phosphate rock from 20.01 wt% (group 1) to 24.24 wt% (group 2) after calcination and, finally, 27.24 wt% (group 3) after calcination, quenching, and disliming. It was further found that the concentration of relevant accompanying rare earth elements (Ce, La, Nd, Pr, Sm, and Y) was increased and that the concentration of Cd could be significantly reduced from 30 mg/kg to 14 mg/kg with the proposed treatment. The resulting phosphate concentrate showed relatively high concentrations in metal oxides: Ʃ MgO, Fe₂O₃, Al₂O₃ = 3.63 wt% and silica (9.81 wt%) so that it did not meet the merchant grade specifications of a minimum P₂O₅ content of 30 wt% yet. Removal of these elements could be achieved using additional appropriate separation techniques.

A number of primary ores such as phosphate rock, gold-, copper- and rare earth ores contain considerable amounts of accompanying uranium and other critical materials. Energy neutral mineral processing is the extraction of unconventional uranium during primary ore processing to use it, after enrichment and fuel production, to generate greenhouse gas lean energy in a nuclear reactor. Energy neutrality is reached if the energy produced from the extracted uranium is equal to or larger than the energy required for primary ore processing, uranium extraction, -conversion, -enrichment and -fuel production. This work discusses the sustainability of energy neutral mineral processing and provides an overview of the current progress of a multinational research project on that topic conducted under the umbrella of the International Atomic Energy Agency.

Phosphogypsum (PG) was used as substrate for the multiplication of eight ornamental species; six by cuttings and two by sowing. The results obtained showed a high rooting or percent germination for the six plants: Ficus benjamina, Pelargonium × Hortorum, Washingtonia filifera, Eucalyptus camaldulensis, Hibiscus rosa sinensis and Acalypha wilkesiana. For a percentage of 50% PG, only F. benjamina, H. rosa sinensis and W. filifera showed high percentage rooting. Plant vigour (height and biomass) depends on both species and treatment. Two species showed high sensitivity to PG during the propagation by cuttings, Nerium oleander and Myoporum laetum. We observed high variation in substrate characteristics; with 50% PG, pH was increased from 2.84 to 6.22, and electrical conductivity (EC) and gypsum concentration were reduced from 15.56 to 4.23 mS/cm from 36.23 to 11.82%, respectively. The results showed the possibility of using PG in nurseries for the multiplication and fertilization of several forest and ornamental plant species by cuttings and sowing.