received by the International Bureau on 2 March 2016 (02.03.2016)

1. Improved ( semi ) continuous method of recovering phosphorous from an aqueous solution comprising the steps of providing the aqueous solution comprising soluble phosphorous ,

adding a composition, the composition comprising as mixed ingredients

5-40% CaO (w/w, relative to a total weight of the composition) ,

10-40% clay mineral,

and 20-60% CaC0₃,

wherein 0.5-2 mole CaO/mole soluble P is added,

and recovering the phosphorous,

wherein the composition is not a calcium silicate hydrate (CSH) .

2. Method according to claim 1, wherein the solution is an acidic solution, the acid aqueous solution having a pH of 1-6, wherein the pH is increased to 5.5-8 by adding the composition, or wherein the solution is a basic solution.

3. Method according to claim 1 or 2, wherein an amount of soluble phosphorous present is in a range of 1-50 ppm (mg/1) , or in a range of 100-1000 ppm (mg/1) , or in a range of 10-250 g/1.

4. Method according to any of claims 1-3, wherein the clay mineral is selected from a natural or artificial clay, the clay preferably being a monovalent cation clay, comprising one or more of H+, Na+, K+, Li+, such as a TOT- clay (or 2:1 clay) or T-0 clay (1:1 clay), such as a kaolin clay, such as kaolinite, dickite, halloysite and nacrite, a smectite clay, such as bentonite, montmorillonite, nontronite and saponite, an illite clay, a chlorite clay, a silicate mineral, such as mica, such as biotite, lepidolite, musco- vite, phlogopite, zinnwaldite, clintonite, and allophane.

5. Method according to any of claims 1-4, wherein the composition comprises

20-30% CaO (w/w) , such as from 25-28%

(w/w) ,

20-35% (meta) kaolin, that may or may not be in the dehydrated form of meta-kaolin, preferably from 25-30% (meta) kaolin (w/w) ,

and 25-50% CaC0₃ (w/w) , such as from 35-45%

(w/w) , and

wherein 0.8-1.2 mole CaO/mole soluble P is added.

6. Method according to any of claims 1-5, wherein the composition is obtained by thermal conversion of a material chosen from paper waste and residue from the paper production .

7. Method according to claim 6, wherein the paper waste or residue from the paper production is thermally treated in a fluidized bed installation having a freeboard in the presence of oxygenous gas, and wherein the fluidized bed is operated at a temperature between 720 °C and 850 °C, and wherein the temperature of the freeboard is 850 °C or below 850 °C, and wherein the fluidized bed is preferably provided with means to promote heat transfer.

8. Method according to any of claims 1-7, wherein the aqueous solution is selected from waste water, treated waste water, sludge, organic acid digest solution, acid digest solution, animal manure, such as pig manure, cow manure, and combinations thereof, and/or

wherein the solution comprises 0.01-6 wt . % solids, and/or

wherein the solution comprises impurities, such as heavy metals, organic matter, and humus.

9. Method according to any of claims 2-8, wherein the pH is increased to 6-7, preferably to 6.2-6.7.

10. Method according to any of the preceding claims, wherein in the composition comprising CaO, the clay mineral, and CaCC>3 are homogeneously distributed.

11. Method according to any of the preceding claims, wherein the composition has a BET surface area of 5-100 m²/gr, such as 10-30 m²/gr.

12. Use of a method according to any of claims 1-11, for forming brushite (CaHPC>4.2H₂0) , wherein the brushite precipitates, and wherein the precipitate is recovered and optionally dried.

13. Product obtained by a. method according to any of claims 1-12, comprising 40-70% brushite (CaHP0₄.2H₂0) , 10-30% calcite (CaC0₃) , 1-10% meta-kaoline (Al₂Si₂0₇) , on an at^¬ om/atom basis, and preferably < 1000 ppm (mg/kg) heavy metals (As, Cd, Cr, Co, Cu, Pb, Hg, Mb, Ni, Se, and Zn) .

14. Use of a product according to claim 13, as a fertilizer.