Investigation into the question of complex processing of bauxites of the srednetimanskoe deposit

Abstract

143From the moment the Bayer method appeared in alumina technology, the notion of the quality of the bauxite raw material has been a constant. The most basic and constantly accompanying impurity of the latter is silica, which almost completely dissolves dur ing the production process, transferring into sodium silicate. In turn, favorable conditions for the interac tion of sodium silicate with components of the alkalialuminate solution appear with the formation of low soluble sodium aluminum silicate hydrate (SASH) of the following chemical composition: Na 2 O ⋅ Al 2 O 3 ⋅ nSiO 2 ⋅ 2H 2 O (n = 1.75-2.00) at elevated tempera tures and the prolonged duration of some processes [1]. Several types of SASH are revealed in alumina industry: nosean, sodalite, cancrinite, zeolite, etc. They differ from each other by the incorporation of various ions in the aluminate solution into the crystal lattice skeleton and by the degree of saturation by sil ica [2]. The main negative consequence of the forma tion of these compounds is the loss of valuable compo nents of the alkali-aluminate solution with silica. Therefore, it is recommended to process the bauxites with a silicon module of ≥6-7 units using the Bayer method. The sintering method is more reasonable for bauxites with smaller silicon modules.Currently, Ural alumina plants operate using a mixture of SUBR and STBR bauxites. In the future they will process only STBR bauxites.Bauxites of the Srednetimanskoe deposit (the STBR bauxite mine) are ore of medium quality; their silicon module is mainly 6-7 units. In connection with this, it is desirable to investigate the behavior of silica in alkali-aluminate solutions.STBR bauxites belong to the boehmite-cha mosite-hematite type with a small diaspore impurity. They are high ferrous, sulfur free, and low carbonate. In contrast to North Ural bauxites (SUBR), where the main alumina containing mineral is diaspore, it is boehmite in STBR bauxites, which is confirmed by the spectral analysis data (Fig. 1). Boehmite is a more chemically active form of aluminum hydroxide when compared with the diaspore of SUBR bauxites.Silica containing minerals of the STBR bauxite are presented by chamosite and kaolinite. A higher cha mosite content is characteristic of low module baux ites. The content of these minerals considerably varies, which is a distinctive feature of bauxites of the Sred netimanskoe group. The main iron containing min eral in STBR bauxites is hematite. Abstract-A new technology of processing raw materials with the use of active alkali is suggested for bauxites of the Srednetimanskoe deposit; bauxite is opened at 300°C for 1 h. This technology makes it possible to increase the recovery of alumina to 94-98% and obtain red slimes and zeolite enriched with iron (58%) and titanium (4.8%); the environmental problem of storing red slimes is resolved. The blast furnace smelting of such slimes makes it possible to obtain naturally doped cast iron and slag enriched with titanium and rare earth metals. When purifying (desiliconizing) the a...

Towards zero-waste valorisation of rare-earth-containing industrial process residues: a critical review

“…Most combined pyro/hydrometallurgical treatments of bauxite residue use a pyrometallurgical step to first recover iron from bauxite residue and to subsequently concentrate the rare earths in an oxide slag (Liu et al, 2009b;Logomerac, 1979a;Logomerac, 1979b;Loginova et al, 2013). The efforts made to extract iron from bauxite residue have been described above.…”

“…During reductive smelting of bauxite residue, 98-99% of the scandium content reports to the slag phase (Tanutrov et al, 2013). Scandium has been recovered from slag obtained by smelting of Chinese bauxite residue, by leaching with 30% H 2 SO 4 , followed by solvent extraction with bis(2ethylhexyl)phosphoric acid in sec-octanol/kerosene diluent, and stripping with NaF solution from the loaded organic phase to obtain Na 3 ScF 6 (Xu and Li, 1996) The combined use of pyrometallurgical and hydrometallurgical methods for recovery of metal values of bauxite residue is called complex processing (Zazubin et al, 1967;Sargic and Logomerac, 1974;Loginova et al, 2013).…”

Increased As Adsorption on Maghemite-Containing Red Mud Prepared by the Alkali Fusion-Leaching Method

“…are then leached under certain conditions to produce iron oxides and hydroxides with a high specific surface area and magnetic properties [64,65]. However, the use of red mud obtained by this method as an adsorbent for arsenic removal without additional treatment has not yet been studied.…”

Alkali Fusion-Leaching Method For Comprehensive Processing Of Fly Ash

“…For example, in this country, about 20% of the generated fly ash being used in concrete production. Other areas of utilization include: land reclamation, ceramic industry, production of catalysts and We have conducted earlier research on the processing of aluminum raw materials [5,6] showed that the fusing aluminum containing minerals with alkali eliminates the need of autoclave or high-temperature processing. To explore the possibility of applying this method for the processing of fly ash studies have been conducted on the fusing of pre-desilicated fly ash with caustic alkali at different temperatures from 100…”