Summary of research progress on separation and extraction of valuable metals from Bayer red mud.

Bayer red mud is a strong alkaline solid waste discharged during alumina production. Due to large emissions and strong alkalinity, red mud is now mostly dammed or buried, which not only occupies huge land but also contaminates the surrounding ecosystem, causing the risk of collapse and landslide. In addition to its overall utilization in building materials, agriculture, the environment, and the chemical industry, red mud also contains valuable metals such as sodium, aluminum, iron, titanium, and scandium and is considered to be an important secondary resource.

Research on the Dealkalization Treatment of Bauxite Residue and Deep Extraction of Alumina.

Bauxite residue is the bulk solid waste generated by the alumina industry, and the environmental treatment of bauxite residue has always been a focus of attention. In this study, in the high calcium system, the bauxite residue was intensively digestion by the calcification-carbonation method, and the mole ratio of solution, the mass ratio of CaO/SiO of the digestion process were changed, so that the high-efficiency dealkalization of bauxite residue was realized and the aluminum oxide in bauxite residue was deeply extracted. The experimental results showed that the calcification process could achieve the recovery of 17.

Study on Iron Extraction from High Iron Bauxite Residue by Pyrite Reduction.

A new method of solid-phase reduction magnetic separation with pyrite as a reducing agent was proposed in order to realize resource utilization of high iron bauxite residue while reducing environmental harm. FeS powder and high iron bauxite residue powder were uniformly blended and roasted in a closed environment. A magnetic separator was utilized to separate the magnetic iron concentrate at 2400 GS, and the recovery rates were calculated.

Calcification-Carbonation Method for Bayer Red Mud Treatment: Carbonation Performance of Hydrogarnets.

Hydrogarnets are vital intermediate products in the calcification- carbonation method, which is designed for Bayer red mud treatment. Their carbonation performance greatly depends on SiO substitution. In this study, different SiO-substituted hydrogarnets were synthesized and characterized.

Extraction and Utilization of Valuable Elements from Bauxite and Bauxite Residue: A Review.

Bauxite is the ideal raw material for the manufacturing of alumina. Aside from the primary constituents of aluminum and silicon, bauxite is frequently coupled with many valuable elements such as gallium (Ga), titanium (Ti), scandium (Sc), and lithium (Li). The bauxite residue and circulating spent liquor in alumina production typically include significant amounts of valuable elements, making them a potential source of polymetallic.

Experimental Research on Vortex Melting Reduction of High-Iron Red Mud (Bauxite Residue).

In this study, the advantages of the vortex melting reduction treatment of red mud were verified. Vortex melting reduction can improve the feeding rate, promote the reaction and the directional deposition of iron, which was conducive to the separation of slag and gold. The effects of different adding methods, stirring speed and reaction time on iron recovery were investigated by using red mud, aluminum leached slag and calcified slag as raw materials.

Comprehensive Application Technology of Bauxite Residue Treatment in the Ecological Environment: A Review.

The emission of bauxite residue continues to grow with the increase of alumina production capacity, along with the large amounts of bauxite residue currently stored in stockpiles. The exposed problems of high yield, strong alkalinity, low comprehensive utilization rate, and threats to the ecological environment are becoming increasingly prominent. With the strict requirements of environmental protection, improving the comprehensive utilization rate of bauxite residue and bulk consumption of bauxite residue has become an urgent issue to be solved.

Research on the oxidation characteristics of zinc sulfite in the zinc oxide desulfurization process.

Aiming at the pollution problem of low-content SO in non-ferrous metal production industry, the oxidation kinetics of zinc sulfite in the zinc oxide desulfurization process was studied. The concentration change of Zn, variation of pH, temperature and apparent activation energy in the oxidation process of two ZnSO samples were investigated systematically. The results indicate that the raw material with different crystal water has little effect on the oxidation kinetic of zinc sulfite.

Recovery of vanadium from calcification roasted-acid leaching tailing by enhanced acid leaching.

Vanadium contained tailing generated from the typical calcium roasting-acid leaching process is contaminant and waste of resource. Atmospheric and pressurized leaching were conducted and compared to recover the vanadium from the vanadium tailing and improve the tailing's environmental quality. Orthogonal experiments were designed and applied for the atmospheric leaching study.

Calcification-carbonation method for red mud processing.

Red mud, the Bayer process residue, is generated from alumina industry and causes environmental problem. In this paper, a novel calcification-carbonation method that utilized a large amount of the Bayer process residue is proposed. Using this method, the red mud was calcified with lime to transform the silicon phase into hydrogarnet, and the alkali in red mud was recovered.