Separation of magnesium from lithium in salt-lake brine through struvite precipitation

•Efficient Li/Mg separation from brine by struvite precipitation at pH 5–6.•The Mg2+ precipitation rate was above 99% and the Mg/Li ratio was reduced to 0.1.•A quick, direct filtration process required after precipitation for reducing Li loss.•Li/Mg separation and Li+ adsorption mechanism were analysed.