Explanation:

Scientists have estimated the quantity of rare earth elements that can be recovered from a toxic byproduct of aluminum extraction

Bayer Process

• Alumina is the main components of bauxite, so bauxite is refined in order to produce Alumina.

• Aluminum is a chemical element, and alumina is an aluminium containing compound.

• Alumina, also called aluminum oxide, synthetically produced Al2O3, a white or nearly colourless crystalline substance that is used as a starting material for the smelting of aluminum metal.

• The Bayer process is the principal way for producing alumina by refining Bauxite.

• Bauxite other than with 30-60% of aluminum oxide contains mixture of silica, iron oxides and titanium dioxide.

• Bayer process of producing alumina can be divided into following four steps: Digestion; Filtration; Precipitation and Calcination.

• In the Bayer process, bauxite ore is mixed with a solution of sodium hydroxide and heated in a pressurized vessel.

• When the resulting sodium aluminate is filtered out, what's left is the toxic residue called red mud.

• There are two strategies to recover REEs from red mud extract only REEs or extract all metals (such as iron, titanium, and sodium) including REEs.

• Uses - The Bayer process was invented to develop a method for supplying alumina to the textile industry (it was used as a mordant in dyeing cotton).

• Bayer discovered that the aluminium hydroxide that precipitated from alkaline solution was crystalline and could be easily filtered and washed was gelatinous and difficult to wash.

Hence both statements are correct.