BODY COMPRISING AN OXIDE OF LANTHANIDE SUPPORTED ON A SULPHUR CONTAINING CARBON BASED PARTICLE AND A METHOD OF PREPARATION THEREOF

Abstract

The invention is directed to a body comprising oxides of lanthanides, in particular holmium oxide (Ho.sub.2O.sub.3), which are supported on a sulphur containing carbon based particle and to a process for producing said body.

Claims

1. Body comprising an oxide of lanthanide, supported on a sulphur containing carbon based particle, wherein said body comprises lanthanide to sulphur in an atomic ratio ranging from 1:0.01 to 1:10 when said lanthanide is selected from the group consisting of La, Pr, Nd, Pm, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, and Lu, or in an atomic ratio ranging from 1:0.06 to 1:10 when said lanthanide is Ce.

2. Body according to claim 1, wherein said body comprises lanthanide and sulphur in a total amount of at least 5 wt. % and at most 90 wt. %, calculated as the total amount of elemental lanthanide and elemental sulphur based on the weight of said body.

3. Body according to claim 1, wherein said body comprises lanthanide and sulphur in a total amount of at least 10 wt. %.

4. Body according to claim 1, wherein said body comprises lanthanide and sulphur in a total amount of at most 80 wt. %.

5. Body according to claim 1, wherein the body comprises elemental carbon in an amount of 5-80 wt. %, based on the weight of said body.

6. Body according to claim 5, wherein the elemental carbon is in the form of amorphous carbon, graphitic carbon and combinations therefore.

7. Body according to claim 1, wherein said carbon based particle further comprises a carbon source material selected from the group consisting of a polymeric matrix; cellulose; cellulose-like material; carbohydrate; active carbon; and combinations thereof.

8. Body according to claim 7, wherein said carbon source material further comprises at least one sulphur group.

9. Body according to claim 1, wherein said lanthanide at least partially comprises a radioactive isotope of said lanthanide.

10. Body according to claim 1, wherein said lanthanide is holmium.

11. Body according to claim 1, having a diameter of 0.01 to 500 m.

12. Body according to claim 1, having a diameter of 1 to 100 m.

13. Body according to claim 1, wherein said body has a sphericity of more than 0.75.

14. Body according to claim 1, wherein said body has a density of >0.8 g/ml to 8.0 g/ml.

15. Body according to claim 1, wherein said body further comprises on its surface one or more functional groups.

16. Body according to claim 15, wherein said one or more functional groups comprise hydrophilic groups and/or active groups.

17. Body according to claim 1, wherein the oxide of lanthanide of the body, is at least partly coated by a layer of an element or an oxide of an element, wherein said element is selected from the group consisting of silicon, titanium, zirconium, hafnium, cerium, aluminium, niobium, tantalum and combinations thereof.

18. Body according to claim 1, wherein said body further comprises other elements selected from the group consisting of iron gadolinium, manganese, phosphorous, iodine, iridium, rhenium and combinations thereof.

19. Process for producing a body which process comprises the steps of: contacting a carbon source material, wherein said carbon source material comprises at least one sulphur group, with an aqueous solution of a salt of a lanthanide, thereby producing a modified carbon source material; drying the modified carbon source material; and subjecting said dried modified carbon source material to pyrolysis under inert conditions.

20. Process for producing a body according to claim 19, wherein said contacting is by ion exchange, impregnation, and/or deposition precipitation.

21. Process for producing a body according to claim 19, wherein said carbon source material is selected from the group consisting of a polymeric matrix; cellulose; cellulose-like material; carbohydrate; active carbon; and combinations thereof.

22. Process for producing a body according to claim 19, wherein the carbon source material comprises at least one sulphur group on the surface of said carbon source material selected from the group consisting of sulphonic acid, sulphoxide, sulphate, sulphite, sulphone, sulphinic acid, thiol, thioether, thioester, thioacetal, thione, thiophene, thial, sulphide, disulphide, polysulphide and sulphoalkyl groups, and combinations thereof.

23. Process for producing a body according to claim 19, wherein the carbon source material comprises at least one sulphonic acid group on the surface of said carbon source material.

24. Process for producing a body according to claim 19, wherein the process comprises loading the carbon source material with a precursor of other elements selected from the group consisting of iron, gadolinium, manganese, phosphorous, iodine, iridium, rhenium and combinations thereof.

25. Process for producing a body according to claim 19, wherein the process further comprises functionalising the body, wherein the body is functionalised with a hydrophilic group and/or an active group.

26. Process for producing a body according to claim 19, wherein the process further comprises at least partly coating the carbon source material either prior to or after contacting the carbon source material with an aqueous solution of a salt of a lanthanide; or the body, in particular the oxide of lanthanide of the body; by a layer of an element or an oxide of an element, wherein said element is selected from the group consisting of silicon, titanium, zirconium, hafnium, cerium, aluminium, niobium, tantalum and combinations thereof.

27. Process for producing a body according to claim 19, wherein said process is followed by a step in which carbon is partly removed from the coated or uncoated body; or, from the coated or uncoated carbon source material prior to the pyrolysis step.

28. Process for producing a body according to claim 27, wherein said carbon source material further comprises a salt of a lanthanide.

29. Process according to claim 1, wherein the oxide of lanthanide is in the form of particles.

Description

EXAMPLES

Example 1

[0092] 30 grams of washed and dried ion exchange resin (Dowex 50WX4 H+ (i.e. a styrene-divinylbenzene polymer matrix functionalised with a sulphonic acid group), Fluka, 200-400 mesh) spherically shaped particles, having a diameter between 34 and 74 micron, was added to 330 grams demi-1120 and stirred at 750 rpm in a glass beaker. To this slurry 17.5 g of holmium nitrate pentahydrate (Ho(NO.sub.3).sub.3.5H.sub.2O, Sigma-Aldrich, 99.9% purity) was added and the mixture was stirred overnight, which resulted in the holmium cations being introduced into the ion exchange resin by ion exchange. Next, the slightly brownish particles were filtered and washed with 300 ml H.sub.2O and 200 ml isopropanol (technical grade, VWR. Drying was performed in an oven with 18.1 g of the holmium loaded ion exchanged resin material under a nitrogen flow of 62 nl/h and was heated to 120 C. for 16 hours overnight. Subsequently, the material was heated to 200 C. with 2 C./min for 2 hours while shaking the reactor several times to keep the material fluidised and dried to a constant weight. The dried material was then pyrolysed by heating to 800 C. (ramp 2 C./min., hold 1 hour) under a nitrogen flow of 16.0 nl/h with fluidisation (i.e. the volume of the bed is increased with a factor 2-3 without blowing particles out of the reactor), which produced a black powder. After the pyrolysis step was completed, the pyrolysed material was allowed to cool to room temperature while being kept under a N.sub.2 flow.

[0093] Finally the pyrolysed material was treated with an excess demi-water with a few droplets of surfactant (Dreft soap for dish washing, which comprises a mixture of 5-15% of anionic surfactants and <5% nonionic surfactants). The suspension was treated in an ultrasonic bath for 60 minutes and subsequently filtered, washed with 500 ml of demi-water and finally with 100 ml i-propanol. The pyrolysed material was dried in an oven at 110 C. for 6 hours and finally the pyrolysed material was sieved over a 100 micron sieve to remove the larger particles. Yield: 11.6 grams of black powder. FIG. 1 shows a SEM image of the obtained material.

Example 2

Comparative, in Accordance with WO-A-2013/144879

[0094] 100.1 grams of a sieve fraction (particles smaller than 70 m) of cellulose spheres (Cellets 90, HARKE Pharma, size 60-125 m) were placed in a 1000 ml round bottom flask and were loaded with holmium nitrate via vacuum impregnation. To this end the cellulose spheres were impregnated via vacuum impregnation with an aqueous solution of holmium nitrate pentahydrate (19 g Ho(NO.sub.3).sub.3.5H.sub.2O, Sigma-Aldrich, 99.9% purity, in 50 ml H.sub.2O) in 5 minutes via a nozzle. The impregnated cellulose spheres were then dried at room temperature After 2 hours the flask was heated in an oil bath of 40 C. and further drying was done for another 7 hours to constant weight. This yielded 119 gram light pinkish powder. The resulting material was sieved over a 100 m sieve and yielded 100 grams of a light pinkish powder. 30 g of this material was then heated in a further drying step in a nitrogen flow of 21 ml/h while heating to 110 C. for 25 hours. Subsequently, the material was heated to 300 C. (ramp 2 C./min, isotherm 1 hour) and then to 800 C. (ramp 2 C./min, isotherm 1 hour) in a pyrolysis step, which resulted in a black powder. After the pyrolysis step was completed, the material was allowed to cool to room temperature while the kept under a N.sub.2 flow.

[0095] Finally the pyrolysed material was were treated with an excess demi-water with a few droplets of surfactant (Dreft soap for dish washing, which comprises a mixture of 5-15% of anionic surfactants and <5% non-ionic surfactants). The suspension was treated in an ultrasonic bath for 60 minutes and subsequently filtered, washed with 500 ml of demi-water and finally with 100 ml i-propanol. The pyrolysed material was dried in an oven at 110 C. for 6 hours and finally the pyrolysed material was sieved over a 100 micron sieve to remove the larger particles. Yield: 7.70 grams of black powder.

Example 3

Comparative

[0096] 30 grams of washed and dried ion exchange resin (Dowex 50WX4 H+ (i.e. a styrene-divinylbenzene polymer matrix functionalised with a sulphonic acid group), Fluka, 200-400 mesh) was added to 330 grams demi-1120 and stirred at 750 rpm in a glass beaker. To this slurry 17.5 g of holmium nitrate pentahydrate (Ho(NO.sub.3).sub.3.5H.sub.2O, Sigma-Aldrich, 99.9% purity) was added and the mixture was stirred overnight, which resulted in the holmium cations being introduced into the ion exchange resin by ion exchange. Next, the slightly brownish particles were filtered and washed with 300 ml H.sub.2O and 200 ml isopropanol (technical grade, VWR). 5 grams of this material were slurried in a 300 ml solution of Na.sub.3PO.sub.4 (3.75 g Na.sub.3PO.sub.4, Sigma-Aldrich, 98% purity in 300 ml demi-water) and stirred at room temperature. After 3 hours the slurry was filtered and washed with 750 ml demi-water. Finally, the material was dried at 70 C. overnight yielding 5.37 grams of material.

Analysis

[0097] ICP analyses were performed on samples of Examples 1-3 using a Thermo-Scientific iCAP 7000 series. Sample preparation was carried out by dissolving the particles in a concentrated HNO.sub.3 solution (Lps, 65% Pro Analysis (P.A.) in a microwave at 230 C. The holmium content of the solutions (10 wt. % HNO.sub.3 matrix) were then measured at 345 and 389 nm after calibration.

[0098] Carbon, nitrogen and sulphur (C, N, S) analyses of samples of Examples 1-3 was performed on a EuroVector Euro EA elemental analyser with additional vanadium pentoxide added to the samples to assure complete oxidation of the samples.

[0099] Powder X-ray diffraction (XRD) patterns of samples of Examples 1-3 were obtained with a Bruker D8 ADVANCE (Detector: SOL'X, Anode: Copper, wavelength: 1.542 , Primary Soller slit: 4, Secondary Soller slit: 4, Detector slit: 0.2 mm, Spinner: 15 RPM, Divergence slit: variable V20, Antiscatter slit: variable V20, Start: 10 2 theta, Stop: 100 2 theta, Stepsize: 0.05 2 theta, Time/step: 8 sec, Sample preparation: Front loading).

[0100] The analysis results of Examples 1-3 are shown in Table 1 below.

TABLE-US-00001 TABLE 1 Holmium Carbon Nitrogen Sulphur Example content content content content No. (wt. %) (wt. %) (wt. %) (wt. %) XRD 1 22.3 55.6 0.2 9.5 Amorphous 2 21.1 68.7 0.6 <0.05 Amorphous 3 22.0 68.0 0.7 9.5 Amorphous

Leaching Test Under Neutral and Acidic Conditions

[0101] 1.00 gram of the material according to Examples 1-3 was immersed in a 25 ml demi-water (pH neutral i.e. pH=7), 3.1 wt. % HNO.sub.3 solution (pH was 0.55 at room temperature) and 10 wt. % HNO.sub.3 solution (pH was 0.11 at room temperature). After 2 h stirring at room temperature at 400 rpm, the material was filtered using a filtering apparatus with Whatman 589/5 filter paper. The holmium content of the filtrate was then analysed by ICP according to the method as described herein above. The results of the leaching experiments for Examples 1-3, with the measured amount of holmium content of the filtrate in ppm by weight are the non-bracketed values shown in Table 2 below. The values shown in brackets in Table 2 below is the holmium content of the filtrate in weight percent, based upon the total amount of holmium present in the 1.00 gram material of Examples 1-3, respectively.

TABLE-US-00002 TABLE 2 Ho content in ppm (wt. %) Solution Example 1 Example 2 Example 3 Demi-water pH = 7 <1 (< 0.01) <1 (<0.01) 15 (0.17) 3.1 wt. % HNO.sub.3 3.7 (0.04) 93 (1.10) 1526 (17.11) 10 wt. % HNO.sub.3 3.6 (0.04) 91 (1.08) 3796 (42.56)

Example 4

SiO.SUB.2 .Coating of Ion-Exchange Resin-Spheres

[0102] 10 grams of washed and dried ion exchange resin (Dowex 50WX4 H+ (i.e. a styrene-divinylbenzene polymer matrix functionalised with a sulphonic acid group), Fluka, 200-400 mesh) spherically shaped particles, having a diameter between 34 and 74 microns was dispersed in a mixture of ethanol and water (96 ml deionised water, 613 ml ethanol). After addition of a surfactant solution (4 ml, 3.8 wt. % Lutensol A05 in deionised water) the mixture was stirred for 30 minutes at room temperature and standard ambient pressure (i.e. 100 kPa). Afterwards, ammonia solution (3.2 ml, 32 wt. %) and an ethanolic tetraethyl orthosilicate solution were added (3.7 ml in 30 ml ethanol) together, which resulted in the hydrolysis/condensation reaction of the TEOS (tetraethyl orthosilicate) and the coating of the spheres with SiO.sub.2. After stirring for 18 h at room temperature and standard ambient pressure (i.e. 100 kPa) the material was separated, washed two times with water and ethanol (50 ml each). Finally, the material was dried in a drying oven at 60 C. for 24 hours yielding an off-white powder.

Example 5

Pyrolysed, SiO.SUB.2 .Coated Holmium Containing Spheres

[0103] 50.02 grams of material comparable to Example 4 was loaded with holmium by adding 18.65 grams of holmium nitrate pentahydrate (Ho(NO.sub.3).sub.3.5H.sub.2O, Sigma-Aldrich, 99.9% purity) to a 400 ml aqueous slurry of this material and stirring the slurry overnight. Next, the slightly brownish particles were filtered and washed with 500 ml demi-H.sub.2O and 500 ml isopropanol (technical grade, VWR), respectively. Drying was performed in an oven at 105 C. overnight. This yielded 53.85 grams of a slightly brownish powder. This holmium loaded, SiO.sub.2 coated material was heated in a pyrolysis step in a fluidised bed at 800 C. for 1 hour. After cooling and air stabilization, the black material was subsequently washed and dried. This yielded 29.77 grams of a black powder that contained 18.7 wt. % of holmium as determined by ICP analyses. C=49.1 wt. %, N=0.5 wt. %, S=7.9 wt. %. FIG. 2 shows a SEM image of the material and table 3 shows the elemental composition of the particles as found by SEM-EDS.

Example 6

Partial Calcination of Pyrolysed, SiO.SUB.2 .Coated Holmium Containing Spheres

[0104] 13.49 grams of a sieve fraction (<60 micron) of the holmium loaded, SiO.sub.2 coated material of Example 5 was heated in a fluidised bed at 455 C. for 10 hours in an air flow (31 nl/h). After cooling down the reactor, washing in water and isopropanol subsequently and drying in an oven at 110 C. overnight, 5.03 grams of a black material was isolated that contained 41.8 wt. % of holmium as determined by ICP analyses. Table 4 shows the elemental composition of the particles as found by SEM-EDS.

Example 7

SiO.SUB.2 .Coating of Holmium Containing Carbon Spheres

[0105] 1.0 gram of the material from Example 1 was dispersed in a mixture of ethanol and water (24 ml deionised water, 150 ml ethanol). After addition of a surfactant (72.5 mg, cetyltrimethylammoniumbromide, 95%, Sigma-Aldrich) the mixture was stirred for 60 minutes at room temperature and standard ambient pressure (i.e. 100 kPa). Afterwards, ammonia solution (0.3 g, 32 wt. %) and an ethanolic tetraethyl orthosilicate solution were added (1.5 ml in 2.5 ml ethanol). After stirring for 18 h at room temperature and standard ambient pressure (i.e. 100 kPa) the material was separated, washed two times with water and ethanol (50 ml each). Finally, the material was dried in a drying oven at 60 C. for 24 h. Yield: 1.3 gram of a black powder. SEM-EDS elemental analyses of the sample revealed the presence of SiO.sub.2 on the outside of the particles.

Example 8

Multiple Holmium Addition Steps

[0106] An aqueous solution of holmium nitrate (4.50 gram of Ho(NO.sub.3).sub.3.5H.sub.2O in 18.02 g demi-H.sub.2O) was added dropwisely to 20.85 grams of oven dried, holmium loaded ion exchange resin (Dowex 50WX4 H+) particles (similar to example 1 before pyrolysis). The resulting material was dried overnight at 110 C. The next day, 22.88 grams of the pinkish material was pyrolised at 800 C. under a nitrogen flow of 62 nl/h for 1 hour. After cooling and air stabilisation, 15.17 grams of a black powder was isolated that contained 33.8 wt. % of holmium by ICP analyses. C=41.2 wt. %, N=0.2 wt. %, S=10.9 wt. %.

Example 9

Monosized Holmium Loaded Carbonized Spheres

[0107] 67.12 g of a suspension of Source30 (GE Healthcare Life Sciences) was placed in a beaker glass and dried in an oven at 110 C. overnight which resulted in 10.65 grams of material. To this was added dropwise a solution of holmium nitrate (16.42 grams of Ho(NO.sub.3).sub.3.5H.sub.2O in 17.56 g demi-H.sub.2O). The wet material was placed in an oven and was dried at 110 C. overnight which resulted in a pinkish powder (23.63 grams). A portion of this powder (16.15 grams) was pyrolysed at 800 C. in a nitrogen flow for 1 hour. After cooling and air stabilisation, and subsequent washing with water and isopropanol, 6.11 grams of a black powder was isolated that contained 54.8 wt. % of holmium by ICP analyses. C=27.8 wt. %, N=0.7 wt. %, S=0.7 wt. %. FIG. 3 shows a SEM image of the material.

Example 10

Cellulose Based, Holmium Loaded Carbonized Particles

[0108] Material based on sulphur containing spherical cellulose was prepared according to a procedure similar to example 9, except now 40 ml of a suspension of Cellufine Max S-h (AMS Biotechnology) was used. Ho=21.4 wt. % (ICP analysis); C=64.0 wt. %, N=1.0 wt. %, S=0.8 wt. %. XRD indicated the material to be completely amorphous. FIG. 4 shows a SEM image of the material.

Example 11

Addition of Hydrophylic Surface Groups

[0109] To 1.0 gram of carbonized holmium containing spheres of example 1 was added a solution of concentrated H.sub.2SO.sub.4 (5 ml, 96%) at room temperature. The slurry was heated to 150 C. overnight without stirring. The next day, after cooling to room temperature, the black powder was washed with an excess of demi-water and was dried in an oven at 110 C. for 8 hours. This H.sub.2SO.sub.4 treated material appeared to be much more hydrophilic compared to the parent material of example 1, indicated by the distribution of the samples in a water-toluene biphasic system. This is demonstrated in FIG. 5, which shows the distribution of particles in a water-toluene biphasic system. Left: example 11; all material is in water phase; Right: example 1; all material is in toluene phase at the interface between water and toluene.

Example 12

SiO.SUB.2 .Coating of Resin Spheres, Alternative Procedure to Example 4

[0110] 10 grams of washed and dried ion exchange resin (Dowex 50WX4 H+ (i.e. a styrene-divinylbenzene polymer matrix functionalised with a sulphonic acid group), Fluka, 200-400 mesh) spherically shaped particles, having a diameter between 34 and 74 microns was dispersed in a mixture of ethanol and water (96 ml deionised water, 460 ml ethanol). After addition of cetyltrimethylammoniumbromide (75 mg, 95% purity, Sigma-Aldrich) the mixture was stirred for 1 hour at room temperature and standard ambient pressure (i.e. 100 kPa). Afterwards, ammonia solution (3.2 ml, 32 wt. %) was added and stirred for another 15 minutes. Subsequently, an ethanolic tetraethyl orthosilicate solution was added (6.3 ml in 75 ml ethanol) together, which resulted in the hydrolysis/condensation reaction of the TEOS (tetraethyl orthosilicate) and the coating of the spheres with SiO.sub.2. After stirring for 18 h at room temperature and standard ambient pressure (i.e. 100 kPa) the material was separated, washed two times with water and ethanol (50 ml each). Finally, the material was dried in a drying oven at 60 C. for 24 hours yielding an off-white powder. The material was analysed by SEM-EDS and the elemental composition is found in table 5.

Example 13

SiO.SUB.2 .Coating of Holmium Containing Resin Spheres

[0111] The ion-exchange resin was loaded with holmium according to the procedure in Example 1 (stopped after drying in oven). 10 grams this sample were dispersed in a mixture of ethanol and water (96 ml deionised water, 613 ml ethanol). After addition of a surfactant solution (4 ml, 3.8 wt. % Lutensol A05 in deionised water) the mixture was stirred for 30 minutes at room temperature and standard ambient pressure (i.e. 100 kPa). Afterwards, ammonia solution (3.8 ml, 32 wt. %) and an ethanolic tetraethyl orthosilicate solution were added (6.7 ml in 100 ml ethanol) together, which resulted in the hydrolysis/condensation reaction of the TEOS (tetraethyl orthosilicate) and the coating of the spheres with SiO.sub.2. After stirring for 18 h at room temperature and standard ambient pressure (i.e. 100 kPa) the material was separated, washed two times with water and ethanol (50 ml each). Finally, the material was dried in a drying oven at 60 C. for 24 hours yielding an off-white powder. After pyrolysis of this material at 800 C. in N.sub.2 a black powder could be isolated that was analysed by SEM-EDS. The elemental composition of the carbonised material can be found in table 6 and a SEM image of the material can be found in FIG. 6.

Example 14

Holmium Containing Resin Spheres Coated With PFA and SiO.SUB.2

[0112] The ion-exchange resin was loaded with holmium according to the procedure in Example 1 (stopped after drying in oven). 10 g of this sample were mixed with furfuryl alcohol (12 g, purity 98%, Sigma-Aldrich) and stirred for 3 hours. After separation, the spheres were washed with ethanol and immediately redispersed in a mixture of ethanol and water (96 ml deionised water, 460 ml ethanol). After addition of cetyltrimethylammoniumbromide (75 mg, 95% purity, Sigma-Aldrich) the mixture was stirred for 1 hour at room temperature and standard ambient pressure (i.e. 100 kPa). Afterwards, ammonia solution (3.2 ml, 32 wt. %) was added and stirred for another 15 minutes. Subsequently, an ethanolic tetraethyl orthosilicate solution was added (6.3 ml in 75 ml ethanol) together, which resulted in the hydrolysis/condensation reaction of the TEOS (tetraethyl orthosilicate) and the coating of the spheres with SiO.sub.2. After stirring for 18 h at room temperature and standard ambient pressure (i.e. 100 kPa) the material was separated, washed two times with water and ethanol (50 ml each). Finally, the material was dried in a drying oven at 60 C. for 24 hours yielding a greyish powder. After pyrolysis of this material at 800 C. in N.sub.2, a black powder could be isolated that was analysed by SEM. The elemental composition by SEM-EDS of the carbonised material can be found in table 7.

SEM Analysis

[0113] Examples 1, 5, 6, 9, 10, 12, 13 and 14 were analysed by SEM which was carried out with a Phenom ProX, Co. Phenom-World B.V. scanning electron microscope equipped with a specifically designed EDS detector to determine elemental composition. FIGS. 1, 2, 3, 4 and 6 show SEM images of examples 1, 5, 9, 10 and 13, respectively. Example 5, 6, 12, 13 and 14 were analysed using energy dispersive X-ray spectroscopy (EDS) to determine the elemental composition. The results of this analysis is shown in Tables 3, 4, 5, 6 and 7, respectively.

TABLE-US-00003 TABLE 3 SEM/EDS measurements of Example 5. Element Symbol Weight Conc. Atomic Conc. C 49.7 74.3 O 15.4 17.2 Si 3.3 2.1 S 6.5 3.7 Ho 25.1 2.7

TABLE-US-00004 TABLE 4 SEM/EDS measurements of Example 6. Element Symbol Weight Conc. Atomic Conc. C 14.7 30.0 O 33.8 51.9 Si 12.3 10.8 S 2.4 1.8 Ho 36.8 5.5

TABLE-US-00005 TABLE 5 SEM/EDS measurements of Example 12. Element Symbol Weight Conc. Atomic Conc. C 45.5 54.8 N 14.0 14.4 O 27.5 24.8 Si 2.1 1.1 S 10.9 4.9

TABLE-US-00006 TABLE 6 SEM/EDS measurements of Example 13. Element Symbol Weight Conc. Atomic Conc. C 42.4 61.8 Ho 19.7 2.1 O 26.9 29.4 Si 8.1 5.1 S 2.9 1.6

TABLE-US-00007 TABLE 7 SEM/EDS measurements of Example 14. Element Symbol Weight Conc. Atomic Conc. C 32.4 50.6 Ho 20.7 2.4 O 31.7 37.1 Si 11.6 7.8 S 3.7 2.2

Example 15

Neutron Activation

[0114] The material of Examples 1, 5, 6 and 9 was activated by neutron irradiation. For Examples 1 and 5 sieve fractions of <50 m were used. Irradiations were performed in the pneumatic rabbit system (PRS) in the reactor facilities in Delft, The Netherlands. The PRS (neutron flux of 5.10.sup.12 cm.sup.2s.sup.1) irradiations were carried out on samples of ca. 200 mg, which were packed in polyethylene vials. The irradiation time was 10 hours. The 10 hours irradiation resulted in an estimated relatively high activity depending on the holmium content

[0115] The raw data of the neutron activation and results of free holmium measurements are shown in Table 8. These data were collected using a Perkin-Elmer Wizard III Wallac, gamma-counter at the facility in Delft.

TABLE-US-00008 TABLE 8 Example Time Ho-166 Counts Ho-166 CPM Result (%) Ex. 1 600.05 342554.67 34897.75 100.0 Ex. 5 600.06 262926.33 26663.01 100.0 Ex. 6 600.02 388931 39786.87 100.0 Ex. 9 600.03 224128.33 22789.75 100.0 Ex. 1 600.04 405 40.5 0.0 Ex. 5 600.04 227 22.7 0.0 Ex. 6 600.04 12074 1208.29 0.6 Ex. 9 600.04 943 94.3 0.1

[0116] Material properties after 10 hours of neutron irradiation are summarised in Table 9, the activity of the material is shown in Table 10.

TABLE-US-00009 TABLE 9 size free weight holmium measurement visual holmium example (mg) content (%) mean (m) result result <1% Ex. 1 203.54 26.9 29.33 passed 0.023 Ex. 5 203.38 18.7 28.09 passed 0.017 Ex. 6 207.85 41.8 35.95 some 0.607 artefacts Ex. 9 203.04 54.8 61.94 passed 0.083

TABLE-US-00010 TABLE 10 measured reactor time pre-calculated activity example position irradiated (GBq) (GBq) e.o.b. GBq Ex. 1 BP3 10 hrs 14 14.3 +0.3 Ex. 5 BP3 10 hrs 9.7 9.1 0.6 Ex. 6 BP3 10 hrs 22.3 22.6 +0.3 Ex. 9 BP3 10 hrs 28.4 23.9 4.5 e.o.b. = end of bombardment.

[0117] FIG. 7 shows the particle size distribution of Example 1 material (sieve fraction of <50 m) after neutron activation as determined with Multisizer volume distribution analysis. The mean is 29.33 m, the distribution 97.3% (range 15-60 m).

[0118] FIG. 8 shows light microscopic graphs of neutron activated microspheres (Example 1; sieve fraction of <50 m), (top left: 100 magnification; top right: 400 magnification; bottom left: 400 magnification; bottom right: 400 magnification).

[0119] FIG. 9 shows scanning electron microscope images of Example 1 material (sieve fraction of <50 m) after neutron activation. The particles are perfectly round.

[0120] FIG. 10 shows an EDS analysis of Example 1 material (sieve fraction of <50 m) after neutron activation, identification of compounds on the surface.

[0121] FIG. 11 shows the particle size distribution of Example 5 material (sieve fraction of <50 m) after neutron activation as determined with Multisizer volume distribution analysis. The mean is 28.09 m, the distribution 99.6% (range 15-60 m, using volume statistics). The values mentioned in the figure express number statistics, rather than volume statistics.

[0122] FIG. 12 shows light microscopic graphs of neutron activated microspheres (Example 5; sieve fraction of <50 m), (top left: 100 magnification; top right: 400 magnification; bottom left: 400 magnification; bottom right: 400 magnification).

[0123] FIG. 13 shows scanning electron microscope images of Example 5 material (sieve fraction of <50 m) after neutron activation. The particles are perfectly round.

[0124] FIG. 14 shows an EDS analysis of Example 5 material (sieve fraction of <50 m) after neutron activation, identification of compounds on the surface.

[0125] FIG. 15 shows the particle size distribution of Example 9 material after neutron activation as determined with Multisizer volume distribution analysis. The mean is 16.94 m, the distribution 91.3% (range 10-60 m).

[0126] FIG. 16 shows light microscopic graphs of neutron activated microspheres (Example 9), (top left: 100 magnification; top right: 400 magnification; bottom left: 400 magnification; bottom right: 400 magnification).

[0127] FIG. 17 shows scanning electron microscope images of Example 9 material after neutron activation. The particles are perfectly round.