Disclosed herein are acid-base leaching methods and systems. Specifically, the systems and methods can include supplying an iron and/or aluminum feed material and an acid to a first reaction chamber; supplying a first leachate comprising iron and/or aluminum salts or cations from the first reaction chamber and a calcium feed material to a second reaction chamber to form a solid comprising iron and/or aluminum; supplying a second leachate from the second reaction chamber comprising alkaline earth metal salts or cations and a base to a third reaction chamber to form a precipitated alkaline earth metal product.

A carbo-chlorination process is disclosed for selectively producing AlCl.sub.3 from an alumina-containing feedstock, comprising introducing the following into a fluidized bed reactor maintained at 600-700 C.: (a) dried and calcined feed stream comprising the alumina-containing feedstock and a carbon feed; (b) chlorinating agent; (c) selectivity agent; (d) dried air; and optionally (e) off-spec AlCl.sub.3. The process further includes removing a vapor stream from the reactor in which preferably about 75-80%, of the alumina present in the reactor is converted to AlCl.sub.3; and also removing a solid raw pozzolan stream from the reactor, wherein about 90-99% of the silica present in the reactor remains unconverted and exits the reactor through the solid raw pozzolan stream. The vapor stream comprising AlCl.sub.3 is purified to create an AlCl.sub.3 product stream comprising preferably greater than about 99.99% AlCl.sub.3. The raw pozzolan product is classified to remove coke and create a final pozzolan product having a strength activity index (SAI) in the range of 80-160, per ASTM 618.

A carbo-chlorination process is disclosed for selectively producing AlCl.sub.3 from an alumina-containing feedstock, comprising introducing the following into a fluidized bed reactor maintained at 600-700 C.: (a) dried and calcined feed stream comprising the alumina-containing feedstock and a carbon feed; (b) chlorinating agent; (c) selectivity agent; (d) dried air; and optionally (e) off-spec AlCl.sub.3. The process further includes removing a vapor stream from the reactor in which preferably about 75-80%, of the alumina present in the reactor is converted to AlCl.sub.3; and also removing a solid raw pozzolan stream from the reactor, wherein about 90-99% of the silica present in the reactor remains unconverted and exits the reactor through the solid raw pozzolan stream. The vapor stream comprising AlCl.sub.3 is purified to create an AlCl.sub.3 product stream comprising preferably greater than about 99.99% AlCl.sub.3. The raw pozzolan product is classified to remove coke and create a final pozzolan product having a strength activity index (SAI) in the range of 80-160, per ASTM 618.

A carbo-chlorination process is disclosed for selectively producing AlCl.sub.3 from an alumina-containing feedstock, comprising introducing the following into a fluidized bed reactor maintained at 600-700 C.: (a) dried and calcined feed stream comprising the alumina-containing feedstock and a carbon feed; (b) chlorinating agent; (c) selectivity agent; (d) dried air; and optionally (e) off-spec AlCl.sub.3. The process further includes removing a vapor stream from the reactor in which preferably about 75-80%, of the alumina present in the reactor is converted to AlCl.sub.3; and also removing a solid raw pozzolan stream from the reactor, wherein about 90-99% of the silica present in the reactor remains unconverted and exits the reactor through the solid raw pozzolan stream. The vapor stream comprising AlCl.sub.3 is purified to create an AlCl.sub.3 product stream comprising preferably greater than about 99.99% AlCl.sub.3. The raw pozzolan product is classified to remove coke and create a final pozzolan product having a strength activity index (SAI) in the range of 80-160, per ASTM 618.

A carbo-chlorination process is disclosed for selectively producing AlCl.sub.3 from an alumina-containing feedstock, comprising introducing the following into a fluidized bed reactor maintained at 600-700 C.: (a) dried and calcined feed stream comprising the alumina-containing feedstock and a carbon feed; (b) chlorinating agent; (c) selectivity agent; (d) dried air; and optionally (e) off-spec AlCl.sub.3. The process further includes removing a vapor stream from the reactor in which preferably about 75-80%, of the alumina present in the reactor is converted to AlCl.sub.3; and also removing a solid raw pozzolan stream from the reactor, wherein about 90-99% of the silica present in the reactor remains unconverted and exits the reactor through the solid raw pozzolan stream. The vapor stream comprising AlCl.sub.3 is purified to create an AlCl.sub.3 product stream comprising preferably greater than about 99.99% AlCl.sub.3. The raw pozzolan product is classified to remove coke and create a final pozzolan product having a strength activity index (SAI) in the range of 80-160, per ASTM 618.