Phase equilibrium of the ternary system of NH_(4)Cl—CaCl_(2)—H_(2)O at 50℃

The equilibrium data on the ternary system of NH_(4)Cl-CaCl_(2)-H_(2)O at 50℃were investigated using the wet-residue method.The experimental results show that there are three pure phase crystal areas of NH_(4)Cl,2NH_(4)Cl·CaCl_(2)·3H_(2)O and CaCl·2H_(2)O,two mixture phase crystal areas of NH_(4)Cl and 2NH_(4)Cl·CaCl·3H_(2)O,and 2NH_(4)Cl·CaCl_(2)·3H_(2)O and CaCl·2H_(2)O in the system.A new hydration double salt(2NH_(4)Cl·CaCl·3H_(2)O)was found in the ternary equilibrium system for the first time.

Template-free synthesis and characterization of K-phillipsite for use in potassium extraction from seawater

Kbphillipsite was prepared using a hydrothermal method. Soluble glass and sodium aluminate were used as raw materials in the absence of an organic template. Investigations regarding the K＋ ions were con- ducted at room temperature to determine the ion-exchange capacity in the seawater sample and the selectivity coefficient of the mixed K＋-Na~ solution. The sample was characterized by X-ray diffraction （XRD）, scanning electron microscopy （SEM）, and energy dispersion spectroscopy （EDS）. The K＋ ion- exchange capacity is 51 mg/g in seawater and the selectivity coefficient is 75.1 in the mixed K＋-Na＋ solution. The sample has a selectivity preference for K＋, and therefore can be used to selectively extract potassium from seawater. The sample composed of Si, Al, K, Na, and O exhibits a cross-like shape and is a typical K-phillipsite structure.

Influences of additives on the crystal habit of potassium chloride

By means of constant control speed cooling crystallization,the influences of four additives,including lead chloride,cadmium chloride,sodium salicylate,and quaternary ammonium salt,on the crystal habit of KCl were investigated.The results show that the crystal habit of KCl is cube without additives,the crystal habit of KCl is ellipsoid-like in the presence of Pb^(2+),the crystal habit of KCl is strip in the presence of Cd^(2+),and the crystal habit of KCl is cavate cube in the presence of sodium salicylate.Xray diffractometry analysis reveals that these additives can change the crystal habit of KCl but not its crystal structure.

A combination process of mineral carbonation with S02 disposal for simulated flue gas by magnesia-added seawater

The desulfurization by seawater and mineral carbonation have been paid more and more attention.In this study,the feasibility of magnesia and seawater for the integrated disposal of S02 and C02 in the simulated flue gas was investigated.The process was conducted by adding MgO in seawater to reinforce the absorption of S02 and facilitate the mineralization of C02 by calcium ions.The influences of various factors,including digestion time of magnesia,reaction temperature,and salinity were also investigated.The results show that the reaction temperature can effectively improve the carbonation reaction.After combing S02 removal process with mineral carbonation,Ca^2+removal rate has a certain degree of decrease.The best carbonation condition is to use 1.5 times artificial seawater(the concentrations of reagents are 1.5 times of seawater)at 80℃and without digestion of magnesia.The desulfurization rate is close to 100%under any condition investigated,indicating that the seawater has a sufficient desulfurization capacity with adding magnesia.This work has demonstrated that a combination of the absorption of S02 with the absorption and mineralization of C02 is feasible.