Enrichment of boron in low-grade paigeite

The enrichment of boron in refractory low-grade paigeite was researched by the technology of reductive roasting, magnetic separation, and fine ore direct-to-furnace. Carbon was matched according to the chemical equivalent of C/O=1 (atom ratio). Roasting experiments were carried out in a muffle furnace in order to investigated the changes of paigeite grade and recovery in the range of 500 to 1450℃. The result shows that iron grains increase with raising roasting temperature. The grade of ore concentrate powder can be reached 14.29% at 1 200℃, which can meet the challenges of the paigeite chemical industry (ω(B₂O₃) ≥ 12%. Over 1200℃ the boron recovery can be reached 14.29%. Little changes in boron grade and recovery take place when the roasting temperature is more than 1350℃. It is concluded that the roasting temperature is determined in the range of 1200 to 1350℃, which can not only satisfy high boron recovery, but also meet the requirement of boron grade in the paigeite chemical industry.