Effects of Concentration of Pore Solution on Stability of Ion‐Absorbed Rare Earth Ore Aggregate

Abstract

The continuous change in solution concentration in ore pores during in situ mineral leaching influences the stability of ore aggregate. In this study, influences of the concentration of ammonium sulfate ((NH4)2SO4) solution on the interaction forces between ore particles were calculated. On this basis, the mechanism by which (NH4)2SO4 solution concentration influences the stability of ore aggregate was analyzed. Furthermore, an empirical formula for estimating the critical (NH4)2SO4 solution concentration for aggregation and dispersion of ore body aggregates with different grain composition was proposed. Some major conclusions were drawn. First, for ore bodies with an initial particle size of less than 0.075 mm, the interaction force between particles was net attraction, with the distance range of this force increasing as the concentration of (NH4)2SO4 solution increased from ≤0.001 to 0.16 mol·L−1, aggregation of ore particles occurring within this distance range. Secondly, for ore bodies with initial particle size of less than 0.075 mm, the interaction force between particles was net attraction, but with the distance range of this force decreasing when the (NH4)2SO4 solution concentration increased from 0.16 to 0.28 mol·L−1, dispersion of ore particles occurring beyond this distance range. Thirdly, for ore bodies with particle sizes of less than 0.038, 0.075 and 0.1 mm, the cation exchange capacity (CEC) was 9.13, 8.96, and 8.8 cmol·kg−1, respectively, and the critical (NH4)2SO4 solution concentration affecting the aggregation and dispersion of ore bodies was 0.12, 0.16, and 0.20 mol·L−1, respectively.

Effects of Salinity and pH on Clay Colloid Aggregation in Ion-Adsorption-Type Rare Earth Ore Suspensions by Light Scattering Analysis

“…In industrial production, the in situ leaching process is mostly used for the extraction of REEs from IREOs. Numerous studies have found that ore body particles will migrate during in situ leaching, which will lead to the existence of ore body pores, thus affecting the ore body permeability [8,9]. From the existing studies, it can be determined that the generation of pores in the leaching process of ionic rare earth is the cause of the change in mineral permeability, while there is little analysis on the interaction between mineral particles, the fundamental cause of mineral migration in the leaching process.…”

Calculation of Shear Layer Thickness of Ionic Rare Earth Particles in Mixture Electrolytes during In-Situ Leaching Process

“…The Si 4+ on the surface is replaced by the isomorphous Al 3+ to form a certain amount of permanent negative charges, which are adsorbed on the surface of clay minerals to maintain a stable state of neutral electricity [32][33][34]. According to references [21,25], the surface potential of 2:2 + 3:2 mixture electrolyte at different concentrations was calculated, which was different from Chariton et al [35,36], who approximated the Zeta potential as the surface potential.…”

“…They regarded the particle surface potential value as infinite. Wang et al [21] found that the thickness of the shear layer varied from 2.10 to 2.7 nm by leaching with different concentrations of (NH 4 ) 2 SO 4 solution. At high electrolyte concentrations, the ion volume effect and dispersion force become very important [22,23].…”