The present disclosure is directed to drive shaft assemblies for a rotary furnace. In one form, a rotary furnace comprises a crucible and a drive shaft assembly. The drive shaft assembly comprises a primary shaft and a secondary shaft coupled with the primary shaft. The secondary shaft comprises: a first portion comprising a refractory alloy, the first portion defining a first end and a second end, where the first end of the first portion is configured to couple with the primary shaft; and a second portion comprising graphite, the second portion defining a first end and a second end, where the first end of the second portion is configured to couple with the second end of the first portion and the second end of the second portion is configured to couple with the crucible.

A method of processing red mud comprising: heating red mud to a predetermined temperature; grinding the red mud to a predetermined particle size; and physically extracting iron components from the red mud; physically extracting aluminum components from the red mud, said physically extracting of aluminum components being separate from the physically extracting of iron components, wherein the steps of physically extracting iron components and physically extracting aluminum components are performed without requiring addition of chemical additives to the red mud.

A method of processing red mud comprising: heating red mud to a predetermined temperature; grinding the red mud to a predetermined particle size; and physically extracting iron components from the red mud; physically extracting aluminum components from the red mud, said physically extracting of aluminum components being separate from the physically extracting of iron components, wherein the steps of physically extracting iron components and physically extracting aluminum components are performed without requiring addition of chemical additives to the red mud.

A system for processing red mud including at least one heating section controlled to heat red mud to a predetermined temperature, a crusher configured to grind the red mud to a predetermined particle size, a first separator for physically extracting iron components from the red mud, and a second separator for physically extracting one or more of aluminum components and titanium components from the red mud, wherein the first and second separators do not require addition of chemical additives to perform the separation.

A system for processing red mud including at least one heating section controlled to heat red mud to a predetermined temperature, a crusher configured to grind the red mud to a predetermined particle size, a first separator for physically extracting iron components from the red mud, and a second separator for physically extracting one or more of aluminum components and titanium components from the red mud, wherein the first and second separators do not require addition of chemical additives to perform the separation.

A hydrogen-plasma rotary kiln furnace reactor and a method of reducing iron ore to iron using the same are disclosed. The hydrogen-plasma rotary kiln furnace includes a rotary kiln furnace and a hydrogen-plasma generator.

A hydrogen-plasma rotary kiln furnace reactor and a method of reducing iron ore to iron using the same are disclosed. The hydrogen-plasma rotary kiln furnace includes a rotary kiln furnace and a hydrogen-plasma generator.