1290 XXXI International Mineral Processing Congress 2024 Proceedings/Washington, DC/Sep 29–Oct 3
substitute. ASTM C-618 protocol was used to qualify the
samples using as criterion the 75% of strength activity
index (SAI) after 28 days metric.
RESULTS AND DISCUSSION
The project team scaled-up processes demonstrated in
prior work to design, construct and operate pilot plants
for the physical and chemical ash separation steps. Figure 6
shows our overall concept of a coal ash processing plant for
enriching REE content of the ash. The plant comprises two
stages, first a physical separation stage, followed by a sec-
ond chemical separation stage. The ash produced from the
coal-fired utility is fed into the physical separation plant via
ash handling/feeder equipment. The physical plant involves
dry and wet processing of the ash to separate it into vari-
ous fractions from which the REE-rich fraction is selected
for further processing in the chemical separation stage. The
chemical separation plant acts upon the REE-rich ash frac-
tion, producing a dry concentrate of REE. This product
will then be available for subsequent REE separation and
Figure 5. Pilot Plant for Chemical Processing (0.5 ton/day capacity)—plant overview (left) hot side operation- digestion and
preconcentration steps (center) and Cold Side Operation—LLX units (right)
Figure 6. Phase II Process for the REY and Sc recovery from coal ash
substitute. ASTM C-618 protocol was used to qualify the
samples using as criterion the 75% of strength activity
index (SAI) after 28 days metric.
RESULTS AND DISCUSSION
The project team scaled-up processes demonstrated in
prior work to design, construct and operate pilot plants
for the physical and chemical ash separation steps. Figure 6
shows our overall concept of a coal ash processing plant for
enriching REE content of the ash. The plant comprises two
stages, first a physical separation stage, followed by a sec-
ond chemical separation stage. The ash produced from the
coal-fired utility is fed into the physical separation plant via
ash handling/feeder equipment. The physical plant involves
dry and wet processing of the ash to separate it into vari-
ous fractions from which the REE-rich fraction is selected
for further processing in the chemical separation stage. The
chemical separation plant acts upon the REE-rich ash frac-
tion, producing a dry concentrate of REE. This product
will then be available for subsequent REE separation and
Figure 5. Pilot Plant for Chemical Processing (0.5 ton/day capacity)—plant overview (left) hot side operation- digestion and
preconcentration steps (center) and Cold Side Operation—LLX units (right)
Figure 6. Phase II Process for the REY and Sc recovery from coal ash