Panel and method for producing a panel

1. A floor, wall, or ceiling panel, comprising:

at least one core layer, the core layer comprising an upper core surface and a lower core surface and at least one pair of opposite side edges;

wherein the at least one core layer has a density in the range of 1350 kg/m 3 to 1550 kg/m 3 and comprises a magnesium oxide cement having a crystal structure expressed as a ternary system of magnesium oxide, a magnesium salt, and water, wherein the magnesium oxide cement comprises at least 30 wt % magnesium oxide;

wherein the at least one core layer does not contain a reinforcing layer or fiberglass; and

wherein the at least one core layer comprises at least 20 wt % natural fibres having an average length between 2 and 10 mm dispersed in the magnesium oxide cement forming a reinforcing network.

2. The panel according to claim 1 , wherein the magnesium oxide cement comprises between 35 and 55 wt % magnesium oxide.

3. The panel according to claim 1 , wherein the average length of the natural fibres is between 2 and 5 mm.

4. The panel according to claim 1 , wherein the natural fibres comprise lignocellulosic fibres.

5. The panel according to claim 1 , wherein the magnesium salt comprises magnesium chloride and/or magnesium sulphate.

6. The panel according to claim 5 , wherein the magnesium oxide cement comprises up to 30 wt % of the magnesium chloride and/or the magnesium sulphate.

7. The panel according to claim 5 , wherein the magnesium crystal structure comprises two stable crystalline phases of a 3-phase form and a 5-phase form.

8. The panel according to claim 1 , wherein the core layer comprises up to 60 wt % natural fibres.

9. The panel according to claim 1 , wherein the magnesium oxide cement comprises magnesium hydroxide.

10. The panel according to claim 1 , wherein the density of the core layer is substantially constant over the entire volume of the core layer, wherein the spatial variation of density is below 10% over the entire volume.

11. The panel according to claim 1 , wherein the core layer has a density in the range of 1400 to 1500 kg/m3.

12. The panel according to claim 1 , wherein at least one pair of opposite side edges of the core layer is provided with complementary coupling parts.

13. The panel according to claim 12 , wherein the complementary coupling parts are configured such that in a coupled state a pretension is existing.

14. The panel according to claim 1 , comprising at least one decorative top layer attached to the upper core surface of the core layer.

15. The panel according to claim 1 , comprising at least one backing layer attached to the lower core surface of the core layer.

16. A method for producing a floor, wall or ceiling panel according to claim 1 , comprising the steps of:

a) forming a magnesium oxide cement damp composition comprising at least magnesium oxide, natural fibres and water,

b) subjecting the magnesium oxide cement damp composition to at least one sieving step;

c) applying at least one layer of the magnesium oxide cement damp composition upon a mould part; and

d) subjecting the layer of magnesium oxide cement damp composition to a force having a pressure of at least 7 MPa.

17. The method according to claim 16 , wherein the magnesium oxide cement damp composition has a moisture content below 50%, or optionally, below 35%, or optionally, below 25%.

18. The method according to claim 16 , wherein the magnesium oxide cement damp composition comprises magnesium hydroxide, magnesium chloride and/or magnesium sulphate.

19. The method according to claim 16 , wherein step d) is performed for a duration between 6 hours and 12 hours.

20. The method according to claim 16 , wherein during step d) the layer of magnesium oxide cement damp composition is subjected to a force having a pressure between 7 MPa and 20 MPa.