SYSTEMS AND METHODS FOR SOLID-PHASE REACTIONS

1 . A method of forming a rare earth metal halide, comprising:

heating a mixture comprising a first solid powder and a second solid powder, wherein:

the first solid powder comprises a first salt,

the first salt comprises a first type of cation and a first type of anion,

the first type of cation is a rare earth metal cation,

the second solid powder comprises a second salt,

the second salt comprises a second type of cation and a second type of anion,

the second type of anion is a halide, and

the rare earth metal halide comprises the first type of cation and the second type of anion.

2 . The method of claim 1 , further comprising mixing the first solid powder and the second solid powder.

3 . The method of claim 2 , wherein the mixing is performed with the use of a high-viscosity mixer.

4 . A method of forming a metal halide, comprising:

mixing and heating a first solid powder and a second solid powder, wherein:

the first solid powder comprises a first salt,

the first salt comprises a first type of cation and a first type of anion,

the first type of cation is a rare earth metal cation, an aluminum cation, or a transition metal cation,

the second solid powder comprises a second salt,

the second salt comprises a second type of cation and a second type of anion,

the second type of anion is a halide,

the mixing is performed with the use of a high-viscosity mixer, and

the metal halide comprises the first type of cation and the second type of anion.

5 . The method of claim 1 , wherein the first salt comprises a third type of cation.

6 . The method of claim 5 , wherein the third type of cation is a rare earth metal cation, an aluminum cation, or a transition metal cation.

7 . The method of claim 5 , wherein less than or equal to 15 at % of the third type of cation initially present in the first salt is present in the metal halide.

8 . A method of forming a metal halide, comprising:

heating a mixture comprising a first solid powder and a second solid powder, wherein:

the first solid powder comprises a first salt,

the first salt comprises a first type of cation and a first type of anion,

the second solid powder comprises a second salt,

the second salt comprises a second type of cation and a second type of anion,

the second type of anion is a halide,

the first salt comprises a third type of cation,

the third type of cation is a rare earth metal cation, an aluminum cation, or a transition metal cation,

the metal halide comprises the first type of cation and the second type of anion, and

less than or equal to 15 at % of the third type of cation initially present in the first salt is present in the metal halide.

9 - 30 . (canceled)

31 . A reactor, comprising:

a volume containing a first solid powder and a second solid powder, wherein:

the volume contains less than 1 wt % liquid, and

the first solid powder and the second solid powder are configured to react in a solid-phase reaction to form a product.

32 . The reactor of claim 31 , wherein the first solid powder comprises a first salt comprising a first type of cation and a first type of anion, and wherein the first type of cation comprises a rare earth metal cation, an aluminum cation, or a transition metal cation.

33 . The reactor of claim 31 , wherein the second solid powder comprises a second salt comprising a second type of cation and a second type of anion, and wherein the second type of anion is a halide.

34 . The reactor of claim 32 , wherein the first salt comprises a third type of cation.

35 . The reactor of claim 34 , wherein the third type of cation is a rare earth metal cation, an aluminum cation, or a transition metal cation.

36 . The reactor of claim 34 , wherein less than or equal to 15 at % of the third type of cation initially present in the first salt is present in the product.

37 . (canceled)

38 . The reactor of claim 31 , wherein the reactor is configured to heat the first solid powder and the second solid powder.

39 . The reactor of claim 31 , further comprising a mixer configured to mix the first solid powder and the second solid powder within the volume.

40 . The reactor of claim 31 , further comprising a heater configured to heat the volume to a temperature such that the maximum temperature within the volume is greater than or equal to 25° C. and less than or equal to 900° C.

41 . The reactor of claim 31 , wherein the reaction volume contains less than 0.1 wt % of the liquid.

42 . (canceled)

43 . The reactor of claim 31 , wherein at least 50 wt % of the first solid powder is made up of solid particles having largest cross-sectional dimensions of greater than or equal to 20 microns and less than or equal to 500 microns.

44 . The reactor of claim 31 , wherein at least 50 wt % of the second solid powder is made up of solid particles having largest cross-sectional dimensions of greater than or equal to 20 microns and less than or equal to 500 microns.

45 - 66 . (canceled)