This post is intended to cover discussion around ore sorters,...

This post is intended to cover discussion around ore sorters, ore concentrators and iron grades. Frequent reference to other companies is unavoidable. The value of the resource will improve if the discussion within this tread can be kept to ore sorters, ore concentration methods and options for dealing with iron including Low intensity magnetic separators - LIMS, and Wet high intensity magnetic separators - WHIMS.

Pure spodumene is about 8% Li₂O while typical overall spodumene JORC resources are in the 1% to 1.6% range with limited freak of nature exceptions above this making 1.4-1.6% high grade. Even across high grade pegmatite deposits, the pegmatite is 80% something else and <20% spodumene. Unless huge amounts of waste rock are to be transported along with the spodumene, some form of concentration is required.

Iron or more precisely Iron Oxide (Fe₂O₃) is one of the impurities that is frequently problematic for Spodumene operations. Within the hydroxide conversion process any elevation in the iron grades in the ore is problematic. One social media post I read noted iron created clinkers that require shut-down maintenance to be removed. Typical Spodumene offtake agreements will limit iron grades in the concentrate to about 1%, although its common for that specific term not to be released.

Iron is also problematic for Dense Media Separation (DMS) concentration processes. DMS works for spodumene concentration because the pegmatite material has a density of ~2.7 times while pure spodumene has a density of ~3.1 to 3.2x. With a cut-off grade around 2.8-2.9x DMS will have waste materials being lighter and will become the float rejects. Spodumene crystals being heavier are the majority of the sink accepts and this process and density setting. This allows Spodumene to concentrate to grades like SC4.8 to SC6.0 and sometimes above. Because Iron is heavy, it tends to also concentrate within the sinks of the DMS process.

If DMS is to produce an acceptable grade then most likely the starting ore starting the DMS process grade needs to be under 1%. Alternatively processes like LIMS/WHIMS need to be successful in lowering the iron grade.