Separation of magnesite and calcite based on flotation solution chemistry

Abstract

The dissolution characteristics of minerals, dissolution of flotation agents in solutions, and equilibrium of dissociations and associations serve as the basis for determining the optimal conditions for the effective components of flotation agents and for evaluating the interaction between flotation agents and minerals. This basis provided the theoretical support for the flotation separation of minerals. Based on this, the flotation separation of magnesite and calcite was realized using sodium dihydrogen phosphate, also known as monosodium phosphate (MSP), as a regulator and dodecylamine (DDA) as a collector. When MSP was used in the DDA system, single-mineral and binary mixed-ore flotation tests revealed that the floatability of calcite was significantly greater than that of magnesite and the separation of magnesite and calcite was more effective, respectively. Zeta potential measurements showed that MSP-containing negative groups could selectively reduce the zeta potential of calcite and promote the adsorption of DDA-containing positive groups on the surface of the calcite. However, this effect was negligible on the zeta potential of magnesite. Due to the stronger affinity of MSP to Ca 2+ than that to Mg 2+ , as demonstrated by Fourier transform infrared and X-ray photoelectron spectroscopy analyses, the MSP was adsorbed onto the surface of calcite primarily by hydrogen bonds rather than magnesite, which promoted the stronger adsorption of DDA-containing positive groups on the surface of the calcite. As a result, the differences in the floatability of magnesite and calcite were enlarged by MSP. Thus, MSP can be utilized an effective regulator for the efficient separation of magnesite from calcite via reverse flotation.

Glyphosate Adsorption from Water Using Hierarchically Porous Metal–Organic Frameworks

“…In a similar manner, P–OH is higher compared to free phosphonate, since Ti–O–P–OH is weaker than P–OH. [ 56 ] These observations strongly suggest that glyphosate is adsorbed through a Ti‐phosphonate coordination. Note that the νP–OH vibration at 932 cm −1 is broader than the others, which suggests that the residual OH group in the coordinated phosphonate interacts with the nearby carboxylic coordination through H‐bonds.…”

“…The most important features are the doublet bands at 1132 and 1110 cm −1 as well as at 932 and 880 cm −1 , which are generally attributed to asymmetric and symmetric νP–O and νP–OH of the phosphonate function in glyphosate, respectively. [ 56 ] Note that the first doublet is slightly red‐shifted compared to free phosphonates (i.e., 1155, 1075 cm −1 ), [ 56 ] which is indicative of a Ti‐phosphonate complex whose νP–O is lower in the comparatively stronger Ti–O–P than in P–OH. In a similar manner, P–OH is higher compared to free phosphonate, since Ti–O–P–OH is weaker than P–OH.…”

Estudio de las propiedades fotocatalíticas de dióxido de titanio modificado con aniones fosfato (PO4 3-) y fluoruro (F-) en reacciones de oxidación y reducción de compuestos orgánicos

“…Connor [59] encontró que los fosfatos se enlazan fuertemente al TiO 2 como especies superficiales bidentadas. Por su parte, Gong [60] describió dos tipos de especies ortofosfato adsorbidos en titania: complejos superficiales bidentados puenteados (TiO) 2 PO 2 con simetría C 2v e iones PO 4 3adsorbidos electrostáticamente con simetría T d . Goswami y colaboradores [61], sintetizaron nanocristalitos de titania fosfatada por el método hidrotérmico y reportaron que la incorporación de los aniones estabiliza la fase cristalina y causa un cambio significativo en el tamaño de cristalito y en sus propiedades texturales.…”