| Potassium chloride is an important source of potash fertilizer in agricultural production,which mainly produced by froth flotation using octadecylamine as collector.However,the flotation process is seriously affected by temperature.Low temperature leads to high collector consumption and poor flotation performance.As a soluble salt,the flotation of potassium chloride is conducted in a saturated salt solution.And the ionic species and ionic strength of the solution causes certain peculiarity.In order to understand the poor performance of KCl flotation at low temperature,the adsorption behavior of amine collectors on the surface of KCl are investigated.?1?The ODA concentration in the saturated salt solution with high ionic strength was masured by the Orange?spectrophotometer and gas chromatography.As for the gas chromatography method,the linear relationship is good with the ODA concentration range of 2×10-5?1×10-4mol/L.To the Orange?spectrophotometric method,the linear relationship was obtained with the ODA concentration range of 1×10-6?2×10-5mol/L.The Orange?spectrophotometric method can be used in wide concentration range and the operation is easy.It is more suitable for the determination of the ODA concentration in saturated KCl solution.?2?The constant temperature static adsorption experiment was conducted to study the adsorption of collectors on potassium chloride crystal particle surface.The experimental results showed that the equilibrium time of adsorption was 4 h.The saturated adsorption capacity increases with the increase of temperature.Compared to the KCl saturated solution,the equilibrium adsorption capacity in the KCl-MgCl2 saturated solution decreases dramatically and adsorption capacity decreased more at low temperature.?3?The kinetic models of pseudo-first-order,pseudo-second-order were used to fit the experimental data to study the kinetics of the adsorption process.The results showed that pseudo-first-order kinetic model is fit for the adsorption of ODA better.Freundlich and Langmuir isotherm models were applied to fit the equilibrium data.It indicates that the Langmuir model is more suitable.The contact angle of KCl was measured by the captive bubble method.With the increase of ODA concentration,the contact angle of KCl increased first,and then tended to be stable.With the decrease of temperature,the contact angle decreased.The contact angle in the KCl saturated solution was bigger than that in the KCl-MgCl2 saturated solution.After ODA,ODA absorption,the FT-IR spectrum of ODA or ODA KCl was observed on the surface of potassium chloride crystal particles instead of sodium chloride crystal particles.?4?The effect of temperature and ionic strength on the KCl flotation recovery of was investigated by micro flotation experiment with ODA as the collector.With the decrease of temperature,the adsorption of ODA on the surface of potassium chloride crystal particles and the flotation recovery of KCl significantly decreased,especially at 0 ? decreased more than 40%.Compared to the KCl saturated solution,the adsorption capacity of ODA and the KCl flotation recovery in the KCl-MgCl2 saturated solution decrease.The researcher in this thesis expands the means of potassium chloride flotation research,enriching its flotation mechanism.It provides the theoretical support for the optimization of production process and the promotion of flotation recovery at low temperature.It has the scientific significance to solve the dilemma of lack of China's potash resources. |
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