一些重要含铝矿物的酸溶性能与物相结构关系的研究

通过化学分析、Ｘ－射线衍射、差热分析和溶出率测定等方法对我国不同产地的一些重要含铝矿物的酸溶性能及其物相组成进行了比较研究．结果表明：三水铝石型矿物在通常条件下直接溶出时，一水软铝石型矿物、粘土型矿物经焙烧后溶出时，其氧化铝溶出率均较高；一水硬铝石型矿物焙烧后经固结保温二次溶出时其氧化铝溶出率可达９０％以上，这些矿物可用作制备硫酸铝。

Ammonia nitrogen removal from aqueous solution using zeolite modified by microwave-sodium acetate

The characteristics of the zeolite modified by microwave and sodium acetate and its sorption of ammonia-nitrogen from simulated water sample were investigated.The results show that the modified zeolite by microwave-sodium acetate(SMMZ)has a high sorption efficiency and removal performance.The ammonia-nitrogen removal rate of SMMZ reaches 92.90%.The surface of SMMZ becomes loose and some pores appear,the specific surface area,total pore volume and average pore diameter increase after modification.Compared to the natural zeolite,SMMZ has a more concentrated pore size distribution in the range of 0-10 nm.The cation exchange capacity(CEC)of SMMZ is higher than that of the natural zeolite.And the ammonia nitrogen removal rate is consistent with the change of CEC.The SMMZ possesses rapid sorption and slow balance characteristics and ammonia-nitrogen sorption is consistent with both Langmuir adsorption isotherm model and Freundlich adsorption isotherm model.The adsorption kinetics of ammonia-nitrogen follows the pseudo-second order kinetic model.

SOL-GEL SYNTHESIS AND LUMINESCENCE OF GREEN LIGHT EMITTING PHOSPHORS ZN_2SIO4/MN^(2+)

Mn^2＋ doped Zn2SiO4 phosphors were synthesized by sol-gel method, and the influence of zinc source, Mn^2＋ dopant concentration and annealing temperature were investigated. Results show that zinc nitrate based precursor with strong green emission intensities is better than zinc acetate based precursor. The intensity of green light emission reaches a peak at 254 nm when the Mn^2＋ dopant concentration is about 5%（ molar percentage）. Structural details of the phosphors were examined through X-ray diffractometry, thermogravimetric and differential thermal analysis. The result indicates that they are both rhombohedral structures, which remain amorphous below 700 ℃ and crystallize completely around 1000 ℃. The luminescent properties of Zn2SiO4/Mn^2＋ phosphors were characterized by excitation and emission spectra.

Mechanical properties of cement mortar in sodium sulfate and sodium chloride solutions

To investigate the mechanical properties of cement mortar in sodium sulfate and sodium chloride solutions, uniaxial compression test and ultrasonic test were performed. Test results show that the relative dynamic elastic modulus, the mass variation,and the compressive strength of cement mortar increase first, and then decrease with increasing erosion time in sodium sulfate and sodium chloride solutions. The relative dynamic elastic moduli and the compressive strengths of cement mortars with water/cement ratios of 0.55 and 0.65 in sodium sulfate solution are lower than those in sodium chloride solution with the same concentration at the420 th day of immersion. The compressive strength of cement mortar with water/cement ratio of 0.65 is more sensitive to strain rate than that with water/cement ratio of 0.55. In addition, the strain-rate sensitivity of compressive strength of cement mortar will increase under attacks of sodium sulfate or sodium chloride solution.

Performance of simultaneous desulfurization and denitration in liquid phase with new-style complex absorbent

Performance of simultaneous desulfurization and denitration using the solution of NaClO2 and NaClO as new-style complex absorbent was investigated experimentally in self-designed bench scale bubbling reactor. The effects of main parameters, such as the concentrations of NaClO2 and of NaClO, solution pH and reaction temperature and so on, on removal efficiencies of SO2 and NOx, were examined, then the optimal conditions were established, in which the molar ratio of NaClO to NaClO2 was 1：1, the reaction temperature was 50℃ and the solution pH was 5.5. The removal efficiencies of SO2 and NO under the optimal conditions were 100% and 89.2%, respectively. The mechanism of simultaneous removal based on complex absorbent was proposed by analyzing the removal products and the electrode potentials of related species, namely SO2 and NO are oxi- dized by chlorite anion, hypochlorite, chlorine dioxide and chlorine contained in complex absorbent. In thermodynamic aspect, simultaneous desulfurization and denitration reactions in liquid phase can happen spontaneously and completely, and are all exothermic reactions. It was confirmed by kinetics that for simultaneous desulfurization and denitration, the reaction order and average activation energy of SO2 were 1 and 21.6 kJ·mol^-1, respectively, and those of NO were 1 and 8.2 kJ·mol^-1, respectively.

Extraction mechanism of rare earths from chloride acidic solution with ammonium-bifunctionalized ionic liquid extractants

A series of ammonium-bifunctionalized ionic liquid extractants （ammonium-Bif-ILEs） combined with a number of anions, in- cluding carboxylic acids and 1,3-diketonates, have been prepared and studied in this report. Their extraction behavior and properties toward rare earth ions （REs（III）） are systematically investigated in chloride media as a function of important param- eters such as aqueous phase pH, salting-out agent concentrations, and extraction temperature. The separation performance of ammonium-Bif-ILEs toward REs（III） are systematically discussed. The results demonstrate that ammonium-Bif-ILEs have a synergistic effect between the cation and anions in separation of REs（III）. The influences of different anions on separation fac- tor （β） values are further studied. By comparison, ammonium-Bif-ILEs containing 1,3-diketonates have more potential appli- cations in La（III）/RE（III） separation than those containing carboxylic acids.