小型冲天炉虹吸式出铁法

介绍一种小型冲天炉,不须经常开启、堵塞出铁口的新的出铁方法。该文对某些小企业、小冲天炉技术改造有一定参考价值。

Conversion of ferric oxide to magnetite by hydrothermal reduction in Bayer digestion process

Digesting aluminum-bearing minerals and converting ferric oxide to magnetite simultaneously in Bayer digestion process is crucially important to deal with high-iron diasporic bauxite economically for alumina production.The reaction behaviors of hydrothermal reduction of ferric oxide in alkali solution were studied by both thermodynamic calculation and experimental investigation.The thermodynamic calculation indicates that Fe3O4 can be formed by the conversion of Fe2O3 at proper redox potentials in alkaline solution.The experimental results show that the formation ratio of Fe3O4 either through the reaction of Fe and Fe2O3 or through the reaction of Fe and H2O in alkaline aqueous solution increases remarkably with raising the temperature and alkali concentration,suggesting that Fe（OH）3- and Fe（OH）4- form by dissolving Fe and Fe2O3,respectively,in alkaline aqueous solution and further react to form Fe3O4.Moreover,aluminate ions have little influence on the hydrothermal reduction of Fe2O3 in alkaline aqueous solution,and converting iron minerals to magnetite can be realized in the Bayer digestion process of diasporic bauxite.

Removal of phosphorus from iron ores by chemical leaching

Alkali-leaching and acid-leaching were proposed for the dephosphorization of Changde iron ore, which contains an average of 1.12% for phosphorus content. Sodium hydroxide, sulfuriced, hydrochloric and nitric acids were used for the preparation of leach solutions. The results show that phosphorus occurring as apatite phase could be removed by alkali-leaching, but those occurring in the iron phase could not. Sulfuric acid is the most effective among the three kinds of acid. 91.61% phosphorus removal was attained with 1% sulfuric acid after leaching for 20 rain at room temperature. Iron loss during acid-leaching can be negligible, which was less than 0.25%.The pH value of solution after leaching with1% sulfuric acid was about 0.86, which means acid would not be exhausted during the process and it could be recycled, and the recycle of sulfuric acid solution would make the dephosphorization process more economical.

Transformation of hematite in diasporic bauxite during reductive Bayer digestion and recovery of iron

The reductive Bayer digestion by using iron powder as reductant is proposed to convert hematite to magnetite and further to dissociate iron minerals from sodium aluminosilicate hydrate(desilication product,DSP)based on the differences of their surface properties.The results show that the differences of surface properties between magnetite and DSP in zeta potential,wettability and solvation trend facilitate magnetite to agglomerate,grow up and thus to dissociate from DSP.The increments of reductant amount and alkali concentration favor the transformation of hematite in digestion with the relative alumina recovery of98.91%.Processing the resultant red mud can obtain qualified iron concentrate with iron grade of approximate60%and recovery of about86%through magnetic separation,resulting in reduction of red mud emission higher than70%.The results are potential to develop a novel technology for processing high iron diasporic bauxite efficiently and provide references for comprehensive utilization of high iron red mud.

Electrogenerative leaching of nickel sulfide concentrate with ferric chloride

In order to utilize the chemical energy in hydrometallurgical process of sulfide minerals reasonably and to simplify the purifying process, the electrogenerative process was applied and a dual cell system was introduced to investigate FeCl3 leaching of nickel sulfide concentrate. Some factors influencing the electrogenerative leaching, such as electrode structure, temperature and solution concentration were studied. The results show that a certain quantity of electrical energy accompanied with the leached products can be acquired in the electrogenerative leaching process. The output current and power increase with the addition of acetylene black to the electrode. Varying the components of electrode just affects the polarization degree of anode. Increasing FeCl3 concentration results in a sharp increase in the output of the leaching cell when c（FeCl3） is less than 0.1 mol/L. The optimum value of NaCl concentration for electrogenerative leaching nickel sulfide concentrate with FeCl3 is 3.0 mol/L. Temperature influences electrogenerative leaching by affecting anodic and cathodic polarization simultaneously. The apparent activation energy is determined to be 34.63 kJ/mol in the range of 298 K to 322 K. The leaching rate of Ni2+ is 29.3% after FeCl3 electrogenerative leaching of nickel sulfide concentrate for 620 min with a filter bag electrode.