Synthesis of Magnetic Manganese Ferrite

MnFe2O4 polycrystalline powders were prepared by the chemical coprecipitation method. When the reaction temperature is above 80 ℃, through depositing and washing, the MnFe2O4 can be obtained directly without calcining. However, when it is below 80 ℃, we have to calcine the precursor in order to obtain MnFe2O4, which does not result in pure spinal structure but a mixture of MnFe2O4 and α-Fe2O3. The powders＇ magnetic property was characterized with a Vibrating Sample Magnetometer. The phase structure, crystal size and lattice constant were presented by an X-ray diffractometer. In addition, the morphology of the powder was observed with a scan electron microscope and a transmission electron microscope.     

沉淀法制备氧化铟锡超细材料的研究进展

沉淀法是氧化铟锡超细材料（ITO）的主要制造方法。对该法工艺作了简要说明,分析了其中的主要影响条件,即反应物浓度、沉淀剂及分散剂、煅烧的温度和时间,并对主要影响条件作了量化说明。     

高稳定性碱性硫脲体系对不同类型金矿的适应性

为考察碱性硫脲体系对不同类型金矿浸出的适应性,选用理化性质不同的6种含金物料,分析了其化学组成及矿物物相,并对其浸出行为进行了研究. 结果表明,稳定剂Na2SO3和Na2SiO3大大降低了碱性硫脲的分解率,随稳定剂浓度的增大,硫脲分解率逐渐降低;而且Na2SiO3对碱性硫脲的稳定效果明显优于Na2SO3,当Na2SiO3浓度为0.3 mol/L时,硫脲的分解率由72.5%降至33.8%. 铁氰化钾为适合碱性硫脲浸金的温和氧化剂. 碱性硫脲体系中金矿物浸出前后物相基本无变化. 所选择的金矿物中均含有大量耗碱物质,使溶液的pH值由12.5很快降至中性,但稳定剂Na2SiO3能维持体系的pH值在12左右,有利于浸出过程的进行. 碱性硫脲体系中伴生金属浸出率小于0.1%,浸金具有显著的选择性. 碱性硫脲体系适合浸出经预处理的物相主要为SiO2的氧化矿,浸金率高达82.68%,为碱性硫脲成功应用于黄金工业生产提供了一定的理论依据.