Processing hard rock lithium minerals or other materials to produce both lithium carbonate and lithium hydroxide

A method of processing an aqueous feed solution comprising lithium sulfate to produce a lithium product, the method comprising the steps of:

• (a) subjecting the aqueous feed solution to a solid/liquid separation, and reacting the aqueous feed solution with sodium hydroxide to produce a first intermediate solution comprising lithium hydroxide and sodium sulfate;
• (b) producing the lithium product wherein producing the lithium product comprises the sub-step(s) of:
• (i) separating a primary lithium product comprising the lithium hydroxide from at least a first portion of the first intermediate solution;
• or
• (ii) reacting a second portion of the first intermediate solution with carbon dioxide to produce a secondary lithium product comprising lithium carbonate.

A method of processing a lithium-containing material to produce a first primary lithium product of lithium hydroxide and a secondary lithium product comprising lithium carbonate, the method comprising the steps of:

• (a) preparing an aqueous feed solution comprising lithium sulfate by reacting the lithium-containing material with sulfuric acid;
• (b) reacting the feed solution with sodium hydroxide to produce a first intermediate solution comprising lithium hydroxide and sodium sulfate;
• (c) separating the primary lithium product comprising lithium hydroxide from a first portion of the first intermediate solution comprising lithium hydroxide and sodium sulfate;
• and
• (d) reacting a second portion of the first intermediate solution with carbon dioxide to produce the secondary lithium product comprising lithium carbonate.

A method of processing an aqueous feed solution comprising lithium sulfate to produce a first primary lithium product of lithium hydroxide and a secondary lithium product comprising lithium carbonate, the method comprising the steps of:

• (a) reacting the feed solution with sodium hydroxide to produce a first intermediate solution comprising lithium hydroxide and sodium sulfate;
• (b) separating the primary lithium product comprising lithium hydroxide from a first portion of the first intermediate solution comprising lithium hydroxide and sodium sulfate;
• and
• (c) reacting a second portion of the first intermediate solution with carbon dioxide to produce the secondary lithium product comprising lithium carbonate.