Efficient enrichment of nickel and iron in laterite nickel ore by deep reduction and magnetic separation

The process of deep reduction and magnetic separation was proposed to enrich nickel and iron from laterite nickel ores.Results show that nickel-iron concentrates with nickel grade of 6.96%,nickel recovery of 94.06%,iron grade of 34.74%,and iron recovery of 80.44% could be obtained after magnetic separation under the conditions of reduction temperature of 1275℃,reduction time of 50 min,slag basicity of 1.0,carbon-containing coefficient of 2.5,and magnetic field strength of 72 kA/m.Reduction temperature and time affected the possibility of deep reduction and reaction progress.Slag basicity affected the composition of slag in burden and the spilling and enriching rate of nickel-iron from a matrix to form nickel-iron particles.Nickel-iron particles were generated,aggregated,and grew gradually in the reduction process.Nickel-iron particles can be effectively separated from gangue minerals by magnetic separation.

Iron Extraction From Oolitic Iron Ore by a Deep Reduction Process

A laboratory experiment was carried out to extract iron from oolitic iron ore by a deep reduction and magnetic separation technique. The raw coal with fixed carbon of 66.54% was used as the reductant. The iron was successfully extracted from the oolitic iron ore which otherwise is nearly impossible to be separated due to its extremely fine-grain and mosaic nature. The results showed that an iron recovery rate of 90.78% and an iron content of 92.53~ of iron concentrate could be obtained by such a technique. The optimized roast temperature is 1 200℃ and time is 60 min. The subsequent magnetic separation was performed by using a magnetic field intensity of 111 kA · m^-1 and a grinding fineness less than 45 μm of 96. 19% for the sintered product.

DEEP REDUCTION OF DARBOUX TRANSFORMATION TO A3×3 SPECTRAL PROBLEM

The Darboux transformation of a 3 × 3 spectral problem which is associated with the higherorder nonlinear Schrodinger equation is given. Some solutions of the higher-order nonlinear Schrodinger equation are provided by taking different "seeds".

还原论抑或加工论:深度学习的根基反思与理论走向

深度学习是学习者透过表象、超越知识、潜入心灵、全面领悟的一种知识学习现象、目标与状态,还原论与加工论是深度学习研究的两个理论原生点。问题、思维与意义是深度学习的三个关节点,回植情景、思维升级是深度学习创建的两大基本路径,贯通型深度学习理论是有机整合还原论与加工论的理念范型。面向未来,深度学习的理论走向是:构筑知识学习的立体世界,构建知识学习的生发链、生态环,建立学习力的系统提升机制。

Selective separation of iron and scandium from Bayer Sc-bearing red mud

In this study,we investigated the separation of iron and scandium from Sc-bearing red mud.The red mud object of our study contained 31.11 wt%total iron(TFe),0.0045 wt%Sc,hematite(Fe_(2)O_(3))and ferrosilite(FeO·SiO_(2))as the main Fe-bearing minerals.The Sc-bearing red mud was treated by a novel deep reduction roasting and magnetic separation process that includes the addition of coke and CaO to extract Fe and enriching Sc from the Sc-bearing red mud.The addition of coke and CaO enhances the transformation of hematite(Fe_(2)O_(3))to metallic iron(Fe~0)and magnetite(Fe_(3)O_(4))as well as the transformation of ferrosilite into metallic iron(Fe~0).The test results show that utilizing the new process a Fe concentrate with a TFe content of 81.22 wt%and Fe recovery of 92.96%was obtained.Furthermore,magnetic separation tailings with Sc content of 0.0062 wt%and Sc recovery of 98.65%were also obtained.The test results were achieved under the following process conditions:roasting temperature of 1373 K,roasting time of 45 min,calcium oxide dosage of 20 wt%,coke dosage of 25 wt%,grinding fineness of90%<0.04 mm,and magnetic field intensity of 0.24 T.The major minerals in the Fe concentrate are metallic iron(Fe~0)and magnetite(Fe_(3)O_(4)).The main minerals in the magnetic separation tailings with a low TFe content of 2.62%are CaO·SiO_(2),Na_(2)O·SiO_(2),FeO·SiO_(2),Ca_(3)Fe_(2)Si_(3)O_(12),CaAl_(2)SiO_6 and CaFe(SiO_(3))_(2).

Multistage desulfurization mechanism to reduce sulfur content of high ferrotitanium prepared using thermite method

High ferrotitanium is used as a deoxidizer and alloying agent in steelmaking processes and is mainly produced using high-cost remelting processes.The thermite method is a simple and low-cost method for preparing low ferrotitanium.However,the high levels of S,Al,and O residues in the product severely restrict its applicability in the low-cost preparation of good-quality high ferrotitanium.In this study,a novel multistage deep reduction method for preparing high-quality high ferrotitanium is proposed,and the multistage desulfurization mechanism is systematically investigated.The results indicate that multistage desulfurization is an effective method for reducing the S content of high ferrotitanium prepared via the thermite method.During the strong desulfurization stage,Ti_(2)S reacts with CaO at the slag-metal interface and produces CaS.The S content decreases,while the O content increases,with the increase of CaO in the CaO-Al_(2)O_(3)-based slag.During the deep desulfurization,Ti_(2)S is deeply reduced by the Ca and produces CaS,thus further reducing the S content.The S content decreases with the incremental addition of Ca and can be reduced to 0.035 wt%after multistage desulfurization.