Roll assemblies including superhard inserts, high pressure grinder roll apparatuses using same, and methods of use

1. A roll assembly for reducing size of a stock material, the roll assembly comprising:

a roll body having an outer surface and having a plurality of recesses in the outer surface; and

a plurality of superhard stud elements each of which is positioned inside a corresponding one of the plurality of recesses and brazed to the roll body, at least some of the plurality of superhard stud elements projecting outwardly from the outer surface of the roll body, the at least some of the plurality of superhard stud elements including:

a tungsten carbide substrate; and

a polycrystalline diamond table bonded to the tungsten carbide substrate, the polycrystalline diamond table including a convex working surface;

wherein the convex working surfaces of the at least some of the plurality of superhard stud elements at least partially define a crushing exterior of the roll assembly; and

a plurality of tungsten carbide stud elements secured to the roll body and at least partially defining the crushing exterior, each of the plurality of tungsten carbide stud elements including a tungsten carbide working surface at least some of the plurality of tungsten stud elements projecting outwardly from the outer surface of the roll body.

2. The roll assembly of claim 1 , wherein the plurality of superhard stud elements spiral about the outer surface of the roll body.

3. The roll assembly of claim 1 , wherein the plurality of superhard stud elements define a plurality of spaced rows of the plurality of superhard elements.

4. The roll assembly of claim 1 , wherein the plurality of superhard stud elements are substantially uniformly spaced from each other.

5. The roll assembly of claim 1 , wherein the polycrystalline diamond table is at least partially leached.

6. The roll assembly of claim 1 , wherein the working surface includes a texture configured to increase friction between the convex working surface and the stock material.

7. A high pressure grinding roll (“HPGR”) apparatus for processing a stock material, comprising:

a first roll assembly including a first crushing exterior, the first roll assembly including:

a roll body; and

a first plurality of superhard stud elements brazed to the roll body, each of the first plurality of superhard stud elements including a substrate bonded to a polycrystalline diamond table including a first working surface, the first working surfaces of the first plurality of superhard stud elements at least partially forming the first crushing exterior, at least some of the first plurality of superhard stud elements projecting outwardly from the first roll body;

a second roll assembly positioned adjacent to the first roll assembly to define a gap therebetween, the second roll assembly including a second roll body and a second plurality of stud elements each of which includes a second working surface, the second working surfaces of the second plurality of stud elements forming a second crushing exterior, at least some of the second plurality of superhard stud elements projecting outwardly from the second roll body;

a motor connected to and configured to rotate at least one of the first roll assembly or the second roll assembly; and

wherein at least one of the first roll assembly or the second roll assembly includes a third plurality of stud elements that at least partially define a corresponding one of the first crushing exterior or the second crushing exterior, each of the third plurality of stud elements including a tungsten carbide working surface, at least some of the third plurality of stud elements projecting outwardly from the first roll body or the second roll body.

8. The HPGR apparatus of claim 7 , wherein the first working surface of each of the first plurality of superhard stud elements is substantially planar or non-planar.

9. The HPGR apparatus of claim 7 , wherein the first plurality of superhard elements spiral about a rotation axis of the first roll assembly.

10. The HPGR apparatus of claim 7 , wherein the first plurality of superhard elements define a plurality of spaced rows of the first plurality of superhard elements.

11. The HPGR apparatus of claim 7 , wherein the first plurality of superhard elements are substantially uniformly spaced from each other.

12. The HPGR apparatus of claim 7 , further comprising a material delivery system configured to deliver the stock material to a location at or near at least one of the first or second roll assemblies.

13. A method of processing a stock material, the method comprising:

rotating a first plurality of stud elements about a first axis in a first direction, at least some of the first plurality of stud elements includes a substrate brazed to a first roll body and bonded to a polycrystalline diamond table that has a first convex working surface, the at least some of the first plurality of stud elements projecting outwardly from the first roll body;

rotating a second plurality of stud elements about a second axis in a second direction, at least some of the second plurality of stud elements including a substrate brazed to a second roll body and bonded to a polycrystalline diamond table that has a second convex working surface, the at least some of the second plurality of stud elements projecting outwardly from the second roll body;

reducing the size of the solid object included in the stock material by contacting the stock material with the first convex working surfaces and the second convex working surfaces; and

wherein at least one of the first plurality of stud elements includes stud elements including a tungsten carbide working surface or the second plurality of stud elements includes stud including a tungsten carbide working surface.

14. The method of claim 13 , wherein the first direction is opposite to the second direction.