A method of preparing an aluminum metaphosphate (ALMP) particulate product includes charging a milling chamber of a ball mill with grinding media and loading an ALMP feedstock into the milling chamber. The ALMP feedstock is milled with the grinding media into ALMP particles at a particle reduction index in a range from 0.25 to 0.5. At a plurality of time steps during a period in which the milling is carried out, a fine fraction of the ALMP particles is removed from the milling chamber while a coarse fraction of the ALMP particles remains in the milling chamber for additional milling. An ALMP particulate product with a particle size distribution having a median particle size in a range from 100 m to 700 m is prepared from the ALMP particles removed from the milling chamber.

A method of preparing an aluminum metaphosphate (ALMP) particulate product includes charging a milling chamber of a ball mill with grinding media and loading an ALMP feedstock into the milling chamber. The ALMP feedstock is milled with the grinding media into ALMP particles at a particle reduction index in a range from 0.25 to 0.5. At a plurality of time steps during a period in which the milling is carried out, a fine fraction of the ALMP particles is removed from the milling chamber while a coarse fraction of the ALMP particles remains in the milling chamber for additional milling. An ALMP particulate product with a particle size distribution having a median particle size in a range from 100 m to 700 m is prepared from the ALMP particles removed from the milling chamber.

A process for producing metastable nanocrystalline alpha-alumina (-Al.sub.2O.sub.3) having particle sizes smaller than 12 nm. Starting crystallites of -Al.sub.2O.sub.3 having a particle size larger than 12 nm, typically on the order of about 50 nm, are ball-milled at low temperatures to produce a nanocrystalline -Al.sub.2O.sub.3 powder having a particle size of less than 12 nm, i.e., below the theoretical room temperature thermodynamic size limit at which -Al.sub.2O.sub.3 changes phase to -Al.sub.2O.sub.3, wherein the powder remains in the -Al.sub.2O.sub.3 phase at all times.

A process for producing metastable nanocrystalline alpha-alumina (-Al.sub.2O.sub.3) having particle sizes smaller than 12 nm. Starting crystallites of -Al.sub.2O.sub.3 having a particle size larger than 12 nm, typically on the order of about 50 nm, are ball-milled at low temperatures to produce a nanocrystalline -Al.sub.2O.sub.3 powder having a particle size of less than 12 nm, i.e., below the theoretical room temperature thermodynamic size limit at which -Al.sub.2O.sub.3 changes phase to -Al.sub.2O.sub.3, wherein the powder remains in the -Al.sub.2O.sub.3 phase at all times.

Disclosed is a mill liner for a grinding mill, a mill liner coupling, a coupling tool, and a method of removing a mill liner for a grinding mill. The mill liner is arranged to be removably mounted to an interior surface of the grinding mill. The mill liner includes a coupling component that forms part of a coupling to connect the liner to a coupling tool for lifting of the liner. The coupling component being may be accessible via the inner surface or the wear surface. The coupling component may be in the form of at least one cavity.

An energy-saving double-bearing vertical grinding mill for dry grinding and shaping, comprising a shell, a permanent magnet variable frequency motor arranged above the shell, a rotating shaft connected with the output end of the permanent magnet variable frequency motor, and a double-spiral rotor arranged on the rotating shaft, wherein a grinding chamber is formed in the shell, wherein an upper bearing and a lower bearing are respectively arranged at top and bottom of the grinding chamber, wherein the upper bearing and the lower bearing are both sleeved on the rotating shaft and are respectively located at upper end and lower end of the rotating shaft, wherein the upper bearing and the lower bearing are both rotatably connected with the rotating shaft, wherein the grinding chamber is filled with a grinding medium.

An energy-saving double-bearing vertical grinding mill for dry grinding and shaping, comprising a shell, a permanent magnet variable frequency motor arranged above the shell, a rotating shaft connected with the output end of the permanent magnet variable frequency motor, and a double-spiral rotor arranged on the rotating shaft, wherein a grinding chamber is formed in the shell, wherein an upper bearing and a lower bearing are respectively arranged at top and bottom of the grinding chamber, wherein the upper bearing and the lower bearing are both sleeved on the rotating shaft and are respectively located at upper end and lower end of the rotating shaft, wherein the upper bearing and the lower bearing are both rotatably connected with the rotating shaft, wherein the grinding chamber is filled with a grinding medium.

A process for purifying a solid that has a contaminant adhered to a surface of the solid includes passing the solid through a mechanical agitator, agitating the solid comprising the contaminant adhered to the surface of the solid in the mechanical agitator, removing at least a portion of the contaminant from the surface of the solid based on the agitating to form a purified solid, and removing the purified solid from the mechanical agitator.

An insert for covering one or more selected surfaces of a discharge end assembly including a discharge end wall of a mill shell partially defined by an outer perimeter wall thereof and a number of pulp lifters mounted on the discharge end wall. The insert is formed to cover the selected surfaces to mitigate wear to which the selected surfaces are subjected when the insert is located in a predetermined position relative to the selected surfaces.

Device for comminuting solids, comprising a container which is driven to reciprocate along a trajectory curve which can be generated by superimposing the movement along at least two axes, which are at an angle to each other, at different frequencies and/or different speeds along each of the axes, with at least one grinding body loosely contained in the container.