The Efficient Improvement of Original Magnetite in Iron Ore Reduction Reaction in Magnetization Roasting Process and Mechanism Analysis by In Situ and Continuous Image Capture

Magnetization roasting followed by magnetic separation is considered an effective method for recovering iron minerals. As hematite and magnetite are the main concomitant constituents in iron ores, the separation index after the magnetization roasting will be more optimized than with only hematite. In this research, the mechanism of the original magnetite improving iron ore reduction during the magnetization roasting process was explored using ore fines and lump ore samples. Under optimum roasting conditions, the iron grade increased from 62.17% to 65.22%, and iron recovery increased from 84.02% to 92.02% after separation, when Fe in the original magnetite content increased from 0.31% to 8.09%, although the Fe masses in each sample were equal. For lump ores with magnetite and hematite intergrowth, the method of in situ and continuous image capture for microcrack generation and the evolution of the magnetization roasting process was innovatively examined with a laser scanning confocal microscope (LSCM) with confocal technology and 3D morphologic technology for the first time. The naturally uneven areas, protogenetic pore edges, and magnetite and hematite edges provided active sites for reduction reactions. The microcracks gradually evolved from the lump ore surface and the edges of magnetite and hematite, which had a direct connection with the efficient improvement in ore reduction.

Influence of the ore reduction method on the percolation leaching efficiency

This paper covers gold leaching from sulfide ores. The data on the silicate, mineral, and grain-size composition are presented for the ore studied. Agitation leaching studies were completed for the combined sample and direct cyanidation dynamics indicators are established for the material sample. For all material with the grain size class of 95 % passing –0.074 mm, the required agitation leaching duration is 9–10 hours; with the material sizes up to 2 mm, the leaching duration shall be at least 22 hours. In order to study the efficiency of using roller presses as an alternative to fine crushing, two percolation leaching tests were conducted for the ore size of –5 mm. The material for the first test was prepared by crushing in a standard jaw crusher and the material for the second test was prepared by crushing in a laboratory press with complex monolayer reduction. It has been found that ore reduction using high-pressure crushers, as compared to standard crushing equipment, allows increasing gold recovery during subsequent leaching by 13.52 %. At the same time, the consumption of sodium cyanide increases by 0.26 kg/t of ore.