Effect of inorganic and organic depressants on the cationic flotation and surface charge of rhodonite-rhodochrosite

Abstract

Silicates (rhodonite, tephroite, spessartine) and the carbonate (rhodochrosite) of manganese are of economic interest in silicate-carbonated manganese ores. The recovery of both mineral classes by flotation constitutes a challenge; rhodochrosite is a slightly soluble mineral that can release Mn 2+ ions in pulp. In this work, the effects of inorganic and organic depressants on the cationic flotation at pH 10 with ether amine acetate and the surface charges of rhodonite and rhodochrosite have been investigated. For rhodonite, the influence of Mn 2+ species on its recovery and surface charge at the conditions of maximum yield with amine has also been investigated. The organic depressants, especially the corn starch, were more effective depressants for both minerals. The poor recovery of rhodonite conditioned with MnCl 2 is probably related to the colloidal Mn(OH) 2 deposition on mineral surface. The increase in the rhodochrosite recovery with increasing water glass content is probably related to its negative value of species adsorbed on the mineral surface, since the rhodochrosite zeta potential, conditioned with this reagent, becomes more negative compared with the mineral without reagent, which attracts the ether ammonium.

Influence of Mn2+ ions on depression of quartz and spessartine in gondite ore

“…This induces the quartz recovery drops in alkaline pH systems. Duarte et al, (2015) used a manganese calcium silicate mineral and provided results about the MnCl 2 depression effects on it. In agreement with the Mn speciation diagram, the manganese species in solution (at pH 10) are Mn 2+ (0.0870 mg/L) and MnOH + (0.0692 mg/L), and such species in solution enable the formation of precipitates like Mn(OH) 2 that adsorb on the mineral surface, causing depression.…”

“…Gondite (an example of protore) is a metasedimentary rock, com-posed of spessartine (Mn 3 Al 2 (SiO 4 ) 3 ), a manganese-aluminosilicate (Souza, 1979), that decomposes into manganese oxide, silica, and alumina by weathering. This manganese oxide crystallizes and becomes pyrolusite in the rock (Faria, 2008), and the high silica content, due to the presence of quartz and spessartine, makes this ore more complex for processing (Andrade, 1978). Nevertheless, considering the probable decline of rich ores deposits, the gondite could be an important source of manganese and thus, more studies that explore the way to process this complex ore are essential for its future application.…”

Effects of Cations/Anions in Recycled Tailing Water on Cationic Reverse Flotation of Iron Oxides

“…This could bring an unexpected change into the physicochemical/electrochemical atmosphere of flotation pulp, affecting mineral floatability as well as dewatering and pumping [3]. Table 1 shows the positive or negative effects of ions, especially cations, Ca 2+ , Mg 2+ , Fe 3+ , Al 3+ , K + , Na + etc., in the reverse/direct flotation of iron oxides [4][5][6][7][8][9][10][11][12][13]. It seems to be complicated to figure out specific effects of these cations on the effectiveness of flotation since they may be detrimental in some cases [5,11,13], while in other cases they may be beneficial to the flotation process [4,[7][8][9][10]12].…”

“…But it is closely related to the properties of minerals floated, type of flotation reagents, especially collector, and valence/concentration of cations as well. Since the promotive effects of these cations mainly occur in the anionic reverse flotation of iron oxides [4,[7][8][9][10] while the competitive effects of them obviously take place in the cationic reverse flotation or anionic direct flotation [5,11,13]. And either promotive or Polymer (i) Promotive adsorption with an increase of concentration and valency strength; (ii) Little effect by NaCl.…”

Selective Flotation of Pyrite from Galena Using Chitosan with Different Molecular Weights

“…Polysaccharide polymers [21][22][23][24] are a hot topic in mineral processing due to their efficiency and degradability as the depressants for the flotation of sulfide ores [25][26][27]. In recent years, there were many reports on the relations between the depression effect of macromolecular depressants and molecular weight (MW), i.e., low molecular weight (LMW: 1 kDa ≤ MW < 50 kDa), medium molecular weight (MMW: 50 kDa ≤ MW < 500 kDa), and high molecular weight (HMW: 500 kDa ≤ MW < 1000 kDa) [28][29][30][31].…”