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Lithium from Oxide Mixtures

IP.com Disclosure Number: IPCOM000240789D
Publication Date: 2015-Mar-02
Document File: 5 page(s) / 679K

Publishing Venue

The IP.com Prior Art Database

Abstract

This paper illustrates the usage of Molten Oxide Mixtures in the refining processes for Li.

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Lithium from oxide mixtures

This paper illustrates the usage of Molten Oxide Mixtures* (MOMs) in the refining processes for Li.

It is shown that these MOMs can easily be fed to the standard refining processes. And even some steps of the standard refining processes could be avoided.

State-of-the-art mineral processing

For the refining of Li and production of Li chemicals (hydroxide, carbonate, oxide, …) from Li containing minerals in the industry two standard flow sheets are used.

1)    Acid Process (Fig. 1)

Comprised of (not limited to) following processing steps:

a.    Li concentrates are calcined / roasted at temperatures of 900°C or higher (typically above 1000°C, and often between 1075°C and 1200°C).

b.    Sometimes the concentrates are cooled and milled (dry or wet milling)

c.    Followed by mixing and acid leaching (often H2SO4 is preferred as leaching agent, higher processing temperature and also higher pressure can boost the leaching)

d.    Other elements contained in the concentrates are precipitated and separated by addition of H2O, CaCO3, Na2CO3 and/or CaO at different levels.

e.    The final solution containing Li is than neutralized, evaporated and/or stripped (often using Na2CO3) resulting in a Li-carbonate. Also precipitation of other Li compounds like: Li-oxalate, Li-hydroxide, Li salts, … is possible.

Fig. 1

2)    Base Process (Fig. 2)

Comprised of (not limited to) following processing steps:

a.    Li concentrates are calcined / roasted at temperatures of 900°C or higher (typically above 1000°C, and often between 1020°C and 1100°C).

b.    Sometimes the concentrates are cooled and milled (dry or wet milling)

c.    Followed by mixing and leaching in water (often pH is adjusted by dosing acid or base solutions, higher processing temperature can enhance and boost the leaching)

d.     Other elements contained in the concentrates are separated of by a solid/liquid separation (thickening and/or filtering) or in some cases; these elements are precipitated out (by pH adjustments).

e.    NaOH (solution) is separated from the Li by evaporation/crystallization. 

f.     Finally the process yields a Li hydroxide (by drying) or other Li chemicals (chemical conversion)

Both processes (“Acid” and “Base”) are widely used in the industry to process Li-containing minerals and many publications and patents exist describing these process and derived optimized processes. 

Molten oxide mixtures (MOMs)

Production of MOMs is a standard output from many metallurgical processes. For example in alloy making often mixed oxides are generated together with the alloys.

These MOMs can be made in a very broad range of compositions. They also can be made in many different ways (sometimes intentionally made or sometimes produced as a by-product from metallurgical processing).

Question / Challenge

 Could molten mixed oxides be a source of Li for Li refining?

Test Setup

Making MOMs:

During different lab scale tests, different synthetic samples of MOMs were prepared by mixing Si,...