Leaching behavior of metals from limonitic laterite ore by high pressure acid leaching

The leaching behavior of metals from a nickeliferous limonitic laterite ore was investigated by high pressure acid leaching process for the extraction of nickel and cobalt.The effects of sulfuric acid added,leaching temperature,leaching time and liquid/solid（L/S） ratio on metals extraction were examined.More than 97% Ni,96% Co,93% Mn,95% Mg and less than 1% Fe are extracted under optimum conditions.Analysis of the high pressure acid leaching residue by chemical and XRD analysis indicates that the residual iron and sulfur are mainly present in phases of hematite and alunite,respectively.The high pressure leaching process provides a simple and efficient way for the high recovery of nickel and cobalt from laterite ore,leaving residue as a suitable iron resource.

Influence of Mechanical Activation on Acid Leaching Dephosphorization of High-phosphorus Iron Ore Concentrates

High pressure roll grinding（HPRG）and ball milling were compared to investigate the influence of mechanical activation on the acid leaching dephosphorization of a high-phosphorus iron ore concentrate,which was manufactured through magnetizing roasting-magnetic separation of high-phosphorus oolitic iron ores.The results indicated that when high-phosphorus iron ore concentrates containing 54.92 mass% iron and 0.76 mass% phosphorus were directly processed through acid leaching,iron ore concentrates containing 55.74mass%iron and 0.33mass%phosphorus with an iron recovery of 84.64%and dephosphorization of 63.79% were obtained.When high-phosphorus iron ore concentrates activated by ball milling were processed by acid leaching,iron ore concentrates containing56.03mass%iron and 0.21mass% phosphorus with an iron recovery of 85.65% and dephosphorization of 77.49%were obtained.Meanwhile,when high-phosphorus iron ore concentrates activated by HPRG were processed by acid leaching,iron ore concentrates containing 58.02mass%iron and 0.10mass% phosphorus were obtained,with the iron recovery reaching 88.42% and the dephosphorization rate reaching 88.99%.Mechanistic studies demonstrated that ball milling can reduce the particle size,demonstrating aprominent reunion phenomenon.In contrast,HPRG pretreatment contributes to the formation of more cracks within the particles and selective dissociation of iron and P bearing minerals,which can provide the favorable kinetic conditions to accelerate the solid-liquid reaction rate.As such,the crystal structure is destroyed and the surface energy of mineral particles is strengthened by mechanical activation,further strengthening the dephosphorization.

Developing laterite nickel ore leaching residue as sustainable blast furnace charge

A kind of leaching residue generated during high pressure acid leaching of laterite nickel ore is creatively prepared as blast furnace charge for ironmaking.Results show that the briquettes with uniform shape,compressive strength higher than 72.3 N/pellet,and cracking temperature over 400℃can be obtained by the non-binder briquetting with water content of 12.2 wt.%and pressure of 30 MPa.After preheating at 975℃for 12 min and roasting at 1225℃for 15 min,the strength of the roasted briquettes can reach 2815 N/pellet,and the iron grade is 59.27 wt.%.And the sulfur content can be simultaneously reduced to 0.067 wt.%.The obtained briquettes achieve adequate reducibility index,reduction degradation index,reduction swelling index,softening and melting temperatures,which are suitable for blast furnace ironmaking.The results show that this method cannot only effectively treat the leaching residue to reduce the risk of environmental pollution,but also realize the utilization of leaching residue.