2008 – AusIMM METPLANT, Perth WA

Abstract:

Titaniferous magnetite deposits are a significant source of vanadium for use in high
strength steel alloying and other chemical applications.

The mineralogy of the deposits varies markedly and the ore characteristics strongly
influencing the process route selected and the metallurgical outcomes.
Characterisation of the ores reveals the presence of magnetite, ilmenite and other
minerals such as spinel hematite and goethite with variable degrees of weathering
along with weathered products of host rock. The standard processing route is to crush,
grind and magnetically recover a concentrate for salt roasting to produce a soluble
vanadate.

Ore beneficiation is practiced to generate an iron based mineral concentrate
containing much of the vanadium with low silica levels of 2%. Typical processing
problems encountered are fine liberation size, over grinding of the magnetite and
variable response to magnetic separation resulting from the weathering profile.

Beneficiation options are restricted, and generally focused on producing a combined
iron and titanium rich concentrate containing vanadium due to the fact that ilmenite
and magnetite and their products of weathering are magnetic and have similar specific
gravities making their separation difficult. The ilmenite usually contains low levels of
vanadium making its separation highly desirable from the iron mineralisation
containing higher levels of vanadium.

Salt roasting of vanadium ores followed by water leaching has been the standard
processing route for many years. The cost of suitable sodium salts, availability of
capital and increasing energy costs and energy availability are critical factors in
determining the viability of aspiring vanadium producers. To date, only Windimurra
has acquired full capital funding, secured energy and sodium salt supplies at suitable
cost that enable the construction of the project. Low overall recoveries of vanadium to
concentrate roasting at up to 1200C are critical cost issues.

In this paper, factors influencing the recovery of vanadium are reviewed and
emerging processing trends explored. The important features of the processing of
titaniferous magnetites have been condensed from the literature, published works,
company websites, our own work and personal communication.

Read the paper here