Lithium (Spodumene) Processing Solution

The spodumene ore challenge

Hard-rock lithium comes mainly from spodumene in granitic pegmatites, alongside quartz, feldspar, mica and iron minerals. Converters need a chemical-grade concentrate around 6% Li2O with tightly controlled iron, so the plant must both upgrade lithium and reject contaminants. Coarse, well-liberated spodumene can be pre-concentrated cheaply by density, while fine, intergrown material must be floated. Xinhai begins every lithium project with a bench and pilot test at its 3,000 m² mineral test center to map liberation and set the DMS-flotation split.

The recommended flowsheet

The most economical spodumene flowsheet pairs dense-media separation with flotation. After three-stage crushing to a DMS feed, coarse ore reports to a heavy-medium circuit where a ferrosilicon medium floats off low-density quartz and feldspar, rejecting a large share of the gangue before any grinding. This DMS pre-concentration cuts grinding energy and flotation reagent cost. DMS middlings and the fine fraction are then ground in a wet ball mill and deslimed on a hydrocyclone to prepare a clean flotation feed.

Flotation removes mica first, then floats spodumene with a fatty-acid collector after surface activation, typically in a JJF flotation machine circuit. Our turnkey spodumene lithium processing plant packages crushing, DMS, grinding and flotation into one line, and the wider flotation equipment range scales cell sizes to throughput. For the full step-by-step, see our spodumene processing flowsheet guide.

Spodumene flotation depends heavily on pulp chemistry. The fresh spodumene surface is activated, commonly with sodium hydroxide conditioning and an attrition or desliming step, before a fatty-acid or hydroxamate collector is added at roughly pH 8-9. Removing slimes is critical: ultrafine particles consume reagent and depress selectivity, which is why desliming on hydrocyclones sits ahead of the rougher. Grind size is a balance, fine enough to liberate spodumene from quartz and feldspar but coarse enough to limit slimes, and that optimum is read off the liberation work done during testing.

DMS is what keeps the operating cost down. By rejecting a large mass of low-density gangue before grinding, the heavy-medium circuit shrinks the tonnage that has to be ground and floated, cutting both energy and reagent spend per tonne of concentrate. The cut point of the ferrosilicon medium is tuned so that liberated spodumene reports to sinks while barren quartz and feldspar float away.

Hitting battery-grade iron limits

Iron is the critical impurity for converters. A high-intensity wet drum magnetic separator removes iron-bearing minerals from the spodumene concentrate so it meets the low-iron specification chemical plants demand. Without this step a high-Li2O concentrate can still be rejected on iron.

Closing the circuit

Concentrate is thickened and filtered to transport moisture, while thickeners recover water from the tailings stream for reuse. Typical results are 70-85% Li2O recovery to a 5.5-6.5% Li2O concentrate, framed against your own testwork rather than promised. For a representative build, review our 2 Mt/a spodumene plant in Zimbabwe. As an EPC+M+O contractor, Xinhai delivers flowsheet design, in-house manufacturing, construction and operator training as a single source. To size a plant to your deposit, contact us for an ore test.