Building material compositions

1. A building material composition prepared from a particulate material selected from the group consisting of particulate polysaccharides and particulate polysaccharide derivatives, wherein the particulate material is prepared by a method comprising:

(a) forming a feed composition comprising a member selected from the group consisting of polysaccharides and polysaccharide derivatives, and 35 wt. % to 99 wt. % of water, based on the total weight of the feed composition, wherein said member is at least one of swelled and dissolved in the feed composition;

(b) contacting, in a mill, the feed composition with a gas stream, thereby converting simultaneously the water of said feed composition into water vapor, and said member of said feed composition into a solid state form of finely particulate material;

(c) separating the particulate material from the gas stream; and

(d) optionally drying the particulate material,

wherein the particulate material contains, in each case based on the total weight of the particles, less than 5 wt. % with a particle size smaller than 15 μm, less than 2 wt. % with a particle size smaller than 10 μm, and less than 1 wt. % with a particle size smaller than 5 μm.

2. The building material composition of claim 1 wherein said feed composition comprises from 50 wt. % to 80 wt. % of water, based on the total weight of the feed composition; said mill is a high rotary speed, gas stream impact mill; and said gas stream is a superheated stream of steam comprising a mixture selected from the group consisting of steam and an inert gas, and steam and air, said superheated stream of steam having a steam content of from 40 wt. % to 99 wt. %, based on the total weight of the superheated stream of steam.

3. The building material composition of claim 1 wherein the polysaccharide derivative is selected from the group consisting of polysaccharide ester, polysaccharide ether and mixtures thereof.

4. The building material composition of claim 3 wherein the polysaccharide ether is selected from the group consisting of cellulose ether, starch ether, guar ether and mixtures thereof.

5. The building material composition of claim 3 wherein the polysaccharide ester is selected from the group consisting of cellulose ester, starch ester and mixtures thereof.

6. The building material composition of claim 1 wherein said building material composition is selected from the group consisting of manually or mechanically applied renders, tile adhesives, floor levelling compositions, jointing fillers, mortars, spraycrete compositions, screeds, cement or lime/sandstone extrudates, filler compositions or distempers, silicate paints, mineral paints and emulsion paints.

7. The building material composition of claim 1 wherein said member is present in said feed composition in an amount totaling from 1 wt. % to 65 wt. %, based on the total weight of the feed composition.

8. The building material composition of claim 2 wherein said member is present in said feed composition in an amount totaling from 20 wt. % to 50 wt. %, based on the total weight of the feed composition.