硫砷铜矿、蓝辉铜矿与铜蓝表面选择性氧化浮选分离研究

针对蓝辉铜矿、铜蓝和硫砷铜矿开展了表面选择性氧化浮选分离研究,并通过矿物表面接触角变化及XPS表面分析,阐明了3种矿物表面选择性氧化反应机制。结果显示,氧化剂次氯酸钙和高锰酸钾均可有效抑制蓝辉铜矿和铜蓝上浮,但对硫砷铜矿可浮性无影响; 在丁铵黑药作用下,硫砷铜矿和蓝辉铜矿接触角均达到90°,经次氯酸钙氧化后,蓝辉铜矿接触角降至15°~30°,硫砷铜矿接触角仍高于86°; XPS分析结果表明,次氯酸促进了蓝辉铜矿表面的氧化,硫元素被氧化为SO₄^2-,以CuSO4形式覆盖在矿物表面,增加了表面亲水性,而硫砷铜矿表面As、Cu和S元素并未发生明显的氧化反应,矿物表面维持较高的疏水性。次氯酸钙实现了蓝辉铜矿与硫砷铜矿表面选择性氧化,强化了两者的浮选分离。     

Rattle‐Type Fe3O4@CuS Developed to Conduct Magnetically Guided Photoinduced Hyperthermia at First and Second NIR Biological Windows

A therapeutic carrier in the second near‐infrared (NIR) window is created that features magnetic target, magnetic resonance imaging (MRI) diagnosis, and photothermal therapy functions through the manipulation of a magnet and NIR laser. A covellite‐based CuS in the form of rattle‐type Fe₃O₄@CuS nanoparticles is developed to conduct photoinduced hyperthermia at 808 and 1064 nm of the first and second NIR windows, respectively. The Fe₃O₄@CuS nanoparticles exhibit broad NIR absorption from 700 to 1300 nm. The in vitro photothermal results show that the laser intensity obtained using 808 nm irradiation required a twofold increase in its magnitude to achieve the same damage in cells as that obtained using 1064 nm irradiation. Because of the favorable magnetic property of Fe₃O₄, magnetically guided photothermal tumor ablation is performed for assessing both laser exposures. According to the results under the fixed laser intensity and irradiation spot, exposure to 1064 nm completely removed tumors showing no signs of relapse. On the other hand, 808 nm irradiation leads to effective inhibition of growth that remained nearly unchanged for up to 30 d, but the tumors are not completely eliminated. In addition, MRI is performed to monitor rattle‐type Fe₃O₄@CuS localization in the tumor following magnetic attraction.     

Surface characteristics,collector adsorption,and flotation response of covellite in oxidizing environment

The surface characteristics, collector adsorption, and flotation response of covellite in the presence of NaClO and FeCl₃ were investigated using micro-flotation tests, X-ray photoelectron spectroscopy (XPS), time-of-flight secondary ion mass spectrometry (TOF-SIMS), and contact angle measurements. The micro-flotation test results indicated that covellite was effectively inhibited by the presence of NaClO and FeCl₃. However, the dosages of these depressants were large, and the conditioning time was long. The results of the XPS and TOF-SIMS analyses indicated that NaClO could oxidize the covellite surface and reduce the active sites of Cu. Oxidation products, including CuO and Cu(OH)₂, were generated on the covellite surface. After the addition of FeCl₃, the precipitation of iron hydroxide on the covellite surface increased the content of hydrophilic species on the mineral surface. Thus, the adsorption of ammonium dibutyl dithiophosphate on covellite surface was prevented, which reduced the floatability of the covellite.     

铜蓝浸出化学动力学研究

模拟生物堆浸工艺条件,在硫酸铁酸性介质体系下,针对浸出温度、氧化还原电位和pH进行铜蓝化学浸出动力学试验研究。结果表明,硫酸铁酸性浸出铜蓝符合典型的缩核模型,速率受表面化学反应控制,而非扩散控制,表观活化能48.94kJ/mol。铜蓝的浸出率与温度和氧化还原电位呈正相关,pH对铜蓝浸出的影响微弱。在初始Fe3+浓度9.2g/L、Fe2+浓度3.0g/L、初始pH=1.00±0.05、氧化还原电位恒定在(720±10)mV(vs.SHE)、40℃条件下浸出288h,铜蓝的浸出率达到42.17%。     

Cu-state evolution during leaching of bornite at 50 °C

The bioleaching of bornite with mixed moderately thermophilic culture at 50 °C was investigated. The intermediary species formed during the leaching of bornite were characterized by XRD and XPS. In addition, the evolution of Cu-state during leaching of bornite was further studied by applying φ_h-pH diagram and cyclic voltammetry. The results showed that the bornite was more likely to be leached at high redox potential. Furthermore, the intermediary sulfides, such as isocubanite, covellite, chalcopyrite, disulfide, and polysulfide, were formed in the course of bornite dissolution. The Cu 2p photoelectron spectrum revealed that the valence of copper in bornite and intermediary sulfide formed in the dissolution of bornite is +1. The bornite and chalcopyrite can be converted into each other, and both can be further converted to covellite and/or chalcocite.     

中条山低品位铜矿地下溶浸的研究

对中条山铜矿峪铜矿的低品位含铜矿石进行了可浸性研究,试验结果表明,经过86h的浸出,单独使用硫酸时铜的浸出率只有68.98%;若加入3.14g/L的Fe3+,可使铜的浸出率提高到74.34%;若再加入5g/L的NaCl助浸,铜的浸出率则可提高到79.98%。化学物相和光学显微图像分析表明,氧化铜的浸出很快就可完成,辉铜矿和斑铜矿也以较快的速度降解为蓝辉铜矿和铜蓝,而铜蓝的浸出反应比较缓慢。     

铜蓝的细菌氧化浸出

研究了福建紫金山铜矿中主要目的矿物之一铜蓝的细菌浸出过程的影响因素,考察了铜蓝纯矿物的浸出特性. 实验室条件下细菌浸出铜蓝纯矿物的适宜条件为：接种量100%,矿浆浓度<5%,初始Fe2+浓度4.0 g/L. 20 d浸出周期内铜蓝浸出率可达60%以上. 通过向纯矿物浸出体系中添加Fe3+、黄铁矿和H2O2,探讨提高溶液氧化电位以强化浸出效果的可能性. 结果表明,添加Fe3+和H2O2对于提高溶液的氧化性效果不显著,同时影响细菌的浸出. 添加黄铁矿则能有效提高浸出过程的氧化电位,以1:2或1:1质量比添加黄铁矿能明显加快铜蓝的细菌浸出速率.     

辉铜矿和铜蓝的浸出机理研究

利用半导体电化学腐蚀原理对辉铜矿和铜蓝浸出机理进行理论分析，研究细菌浸出低品位含铜矿石的机理和动力学，并对部分原矿和浸出渣进行了光学显微分析。试验结果证实了辉铜矿在浸出过程中产生一系列具有不同组成的中间产物。随着铜硫比的降低，中间产物浸出所需的氧化还原电位越来越高，铜的浸出越来越困难。     

混合硫化矿在硫酸铁体系下的浸出动力学研究

在硫酸铁酸性介质体系下,为揭示次生硫化铜矿堆浸过程中铜蓝与黄铁矿的浸出过程,利用纯矿物进行浸出模拟试验。纯矿物电位控制试验结果的化学动力学分析表明:铜蓝与黄铁矿浸出速率受表面化学反应控制,500mV(vs.Ag/AgCl)浸出条件下,黄铁矿浸出速率的提升量比铜蓝高出1倍,黄铁矿对电位表现出更强的相关性。结合低品位次生硫化铜矿生物浸出生产实际,进行了实际矿石柱浸验证试验,电位调控能使铁浸出率最高降低2个百分点,控制电位浸出的方式为次生硫化铜矿生物堆浸的过程控制提供了参考。