Amorphous submicron particles

1. A process for milling amorphous solids using a milling apparatus, comprising:

operating a mill in a milling phase with an operating medium selected from the group consisting of gas, vapour, steam, a gas containing steam and mixtures thereof, and

heating a milling chamber in a heat-up phase before the actual operation with the operating medium in such a way that a temperature in the milling chamber, the mill exit or both, is higher than a dew point of the operating medium.

2. The process according to claim 1 , wherein said mill is a is a fluidized-bed opposed jet mill or a dense-bed jet mill or a spiral jet mill.

3. The process according to claim 1 , wherein the milling apparatus or the mill is operated in the heat-up phase with a heating gas which is i) hot gas, ii) a gas mixture or iii) a mixture of hot gas and a gas mixture.

4. The process according to claim 3 , wherein i) the hot gas, ii) the gas mixture or iii) the mixture of hot gas and a gas mixture is passed into the milling chamber during the heat-up phase through inlets which differ from those through which the operating medium is let down during the milling phase.

5. The process according to claim 3 , wherein i) the hot gas, ii) the gas mixture or iii) the mixture of hot gas and a gas mixture is passed into the milling chamber during the heat-up phase through inlets through which the operating medium is also let down during the milling phase.

6. The process according to claim 3 , wherein the inlets for the heating gas and/or the inlets for the operating medium are arranged in a plane in a lower third of the milling chamber in such a way that heating jets and/or milling jets all meet at a point in an interior of a milling container.

7. The process according to claim 1 , wherein dry gas or a dry gas mixture is passed through the mill for cooling.

8. The process according to claim 1 , wherein condensation of steam on assemblies and/or components of the milling apparatus or of the mill is prevented.

9. The process according to claim 1 , wherein a temperature of the operating medium in the milling phase is in the range of 200 to 800° C.

10. The process according to claim 1 , wherein a pressure of the operating medium in the milling phase is in the range of 15 to 250 bar.

11. The process according to claim 1 , wherein classification of the milled material is effected.

12. The process according to claim 11 , wherein the classification is effected by an integrated dynamic paddle wheel classifier, air classifier or combinations thereof.

13. The process according to claim 11 , wherein a jet mill comprising an integrated dynamic air classifier is used, wherein a speed of a classifying rotor or wheel of the air classifier and the internal amplification ratio V (=Di/DF) are chosen or set so that a circumferential speed of the operating medium (B) at a dip tube or outlet nozzle coordinated with the classifying wheel reaches up to 0.8 times the sound velocity of the operating medium.

14. The process according to claim 12 , wherein a milling apparatus is used in which flushing of a gap between a classifying wheel and a classifier housing and/or a shaft lead-through between a classifying wheel shaft and the classifier housing can be carried out.

15. The process according to claim 11 , wherein a jet mill is used which comprises an integrated dynamic air classifier which contains a classifying wheel and a classifying wheel shaft and a classifying wheel housing,

wherein a classifier gap is formed between the classifying wheel and the classifying wheel housing and a shaft lead-through is formed between the classifying wheel shaft and the classifier housing, and

wherein flushing of classifier gap and/or shaft lead-through with compressed gases of low energy content is effected.

16. The process according to claim 12 , wherein an amount of milling gas which enters the classifier is regulated so that the median particle size (TEM) d 50 of a milled material obtained is less than 1.5 μm and/or the d 90 value is <2 μm and/or the d 99 value is <2 μm.

17. The process according to claim 1 , wherein the amorphous solids are gels or particles containing aggregates and/or agglomerates.

18. The process according to claim 1 , wherein amorphous particles which have already been subjected to a drying step are milled.

19. The process according to claim 1 , wherein a filter cake of amorphous particles or a hydrogel is milled or simultaneously milled and dried.