含碳球团高温抗压强度的实验测定

采用自制的高温抗压强度测定装置,研究了使用有机黏结剂的含碳球团在不同温度、气氛条件下高温强度随时间的变化.试验结果表明,采用有机黏结剂“CC”的含碳球团在800℃下保温1 h,球团仍能保持较高的高温强度（30～40 N/球）.在球团开始显著的自还原反应之前,球团高温强度主要由有机黏结剂来保证;而在还原反应（1 000℃以上）之后,球团高温强度则主要依靠还原的大量金属铁;球团的高温强度能满足转底炉生产工艺的要求.     

低品位高含泥氧化铜矿的制粒堆浸新工艺研究

目前，堆浸技术处理低含泥量的低品位氧化铜矿已经取得了令人满意的效果，且实现了工业化生产；但对高含泥量的低品位氧化铜矿，由于其渗透性能差，堆浸工艺尚不成熟．本研究选取含泥量高的低品位氧化铜矿石。分别进行了搅拌浸出试验和制粒柱浸试验，研究了矿石的浸出行为、制粒条件等．试验结果表明：采用酸法制粒堆浸效果良好，浸出液峰值浓度较高，浸出率大于90％，酸耗较低，约为6％；矿石浸出后，颗粒保持完好，矿柱渗透性能良好；此类型的矿石采用酸法制粒浸出工艺在技术上可行．     

低品位金矿堆浸法提金研究

本文介绍了我国六种金矿类型的二十二个矿区氧化矿石的实验室住式堆浸试验结果,和高岭土化蚀变破碎带金矿氧化矿石的制粒堆浸工业试验;对影响堆浸的诸因素进行了系统的研究;探讨了全浸出过程的动力学特性.这些对堆浸提金工艺的推广应用,有一定的指导意义.     

内配碳红土镍矿球团制备工艺

以红土镍矿作为原料,煤粉作为还原剂,氧化钙作为熔剂,配加一定量的黏结剂和水,经对辊压球机压制成含碳球团.对红土镍矿的成球特性进行了研究,考察了还原剂、水分和黏结剂等因素对球团强度的影响.结果表明:红土矿粉本身具有较好的成球特性,在不加入黏结剂的条件下,球团仍具有一定的强度;较细粒度的煤粉会降低球团的强度,适宜含量的较粗粒度的煤粉能提高球团的强度;随着水分加入量的提高,球团的抗压强度逐渐提高,当水的质量分数为18%时,其抗压强度达到最大值,若水分继续增加,抗压强度呈现下降的趋势;球团的落下强度随着水量的增加而升高;随着膨润土用量的增加,球团强度有明显的提高,当膨润土的质量分数为2%时球团强度达到最大值,随着膨润土用量的进一步提高,球团强度略微下降,且膨润土中含有较高含量的SiO2和Al2O3,会降低球团有用元素的品位,因此用量不宜过高.     

有机黏结剂强化铁精矿的成球性能

通过造球试验、红外光谱分析、动电位测定、接触角测量和黏度测定研究了有机黏结剂提高磁铁矿精矿球团强度的效果及作用机理.结果表明,以瓜尔胶(Guar)为黏结剂时湿球强度最大,羧甲基纤维素(CMC)次之,羧甲基淀粉(CMS)最小;干球强度则与黏结剂用量成显著正相关.红外分析表明,CMS和CMC主要通过羧基和羟基吸附在铁精矿表面,Guar主要通过羟基吸附在铁精矿表面.CMS和CMC使铁精矿表面电负性增强,Guar使其电负性减弱;三种有机黏结剂吸附在磁铁矿精矿表面,皆使其表面接触角减小,亲水性增强.黏结剂浓度相同时,溶液黏度越大,湿球强度越大.     

程潮铁矿球团配加黏结剂试验研究

对程潮铁矿高压辊磨前后的铁精矿分别添加膨润土、有机黏结剂、复合黏结剂进行造球试验。结果表明,单独添加少量的膨润土或有机黏结剂,其生球爆裂温度指标合格,生球强度指标不合格;采用膨润土质量分数为2.0%、有机黏结剂质量分数为0.05%的复合黏结剂,其生球抗压强度为14.5N/个、生球落下强度为(0.5m)12.1次/个、生球爆裂温度为630℃、成品球抗压强度为3 024N/个,球团质量有较大的提高。     

球团预制-硅热还原炼镁的球团传热性研究

针对皮江法炼镁存在的问题,提出将白云石粉、硅铁、萤石及黏结剂混合造球,然后煅烧,煅烧后的热球团直接用于还原的炼镁新技术.采用稳态平板法测定了预制球团的导热系数,并通过数值方法研究预制球团的传热规律.结果表明:导热系数随着平均温度提高而增加,随着球团密度和硅铁添加量的增加而降低.当密度为1.1 g/cm~3、硅铁为理论添加量时,预制球团的导热系数与温度的关系:λ=1.04×10~(-4)T+0.11;球形球团的传热情况优于圆柱形球团,球团具有较小的密度和热容以及较大的导热系数有助于热量由表面向中心传递.预制球团与皮江法球团的传热情况基本相同.     

高岭土胶结型铀矿的酸法制粒堆浸研究

对于高岭土胶结型铀矿,由于矿石渗透性太差而无法采用常规的堆浸工艺处理.但对矿石进行酸法制粒预处理后和串联堆浸工艺后,矿石的渗透性能可达到500L/m2.h以上,浸出的合格液平均铀浓度大于5g/L,矿石的铀金属浸出率超过95%,渣品位低于0.02%.而酸耗仅为3.33%.     

球团预制-硅热还原炼镁还原罐内传热

为了解决皮江法还原罐内传热慢的问题，提出将白云石粉、硅铁、萤石混合，加入黏结剂先造球再煅烧，煅烧后的热球团直接用于还原的炼镁新技术.采用数值方法研究预制球团在还原罐内的传热规律.结果表明:提高硅铁添加量、增加球团直径、减小床层密度均有利于热量向还原罐内部传递;将边界温度由1473K提高至1498K，还原罐中心区域达到1473K的时间由300min缩短至178min;当还原罐直径为300mm时，对于直径为25mm的预制球团，还原罐中心点加热至1473K的时间为90min，而对于皮江法球团则需要288min.     

不锈钢除尘灰冷固结成型影响因素研究

针对不锈铜除尘灰粒度细、亲水性差、难成型的特点,本文采用改性淀粉与钠基膨润土复合黏结剂对不锈钢除尘灰进行了成型试验,利用其TFe高的特点,制备出可供高炉冶炼使用的含铁团块,实现对不锈钢除尘灰的回收利用。研究了复合黏结剂添加量、闷料时间、成型压力以及成型水分等因素对成型的影响,结果表明,适宜的复合黏结剂添加量为7．5％;闷料时间为24h;成型压力为25MPa;水分为18％,制得的团块平均抗压强度达到3．3MPa以上,落下强度达到70％以上,可以满足高炉冶炼再使用。     

高碱氧化铜矿堆浸过程中的化学沉淀与调控

以高碱氧化铜矿为研究对象,运用电镜扫描技术、X线衍射技术研究堆浸过程中化学沉淀的成分及沉淀物的表面形貌,并通过添加不同的防垢剂对化学沉淀进行调控.研究结果表明:CaSO4.2H2O沉淀是堆浸过程中化学沉淀的主要成分,属于一类沉淀物,不受pH控制.CaSO4·2H2O沉淀结晶受饱和度影响,扩散机制是晶核生长的主导机制.防垢剂对CaSO4·2H2O沉淀具有明显的溶蚀作用,其中以水解聚马来酸酐HPMA对CaSO4.2H2O的溶解效果最好,其添加量与对CaSO4·2H2O沉淀溶蚀能力呈指数函数关系,Ca2+的浓缩倍数最高可达到1078.54％.     

赞比亚低品位难处理铜钴矿湿法冶金新工艺

以赞比亚某低品位难处理铜钴矿石为研究样本,采用全湿法冶金方法,开展新工艺研究.研究可知:矿石Cu,Co和S质量分数分别为1.270%,0.071%,0.022%.矿石中铜矿物主要为假孔雀石和少量的孔雀石.钴矿物主要为钴锰矿和水钴矿,在褐铁矿和黑云母晶体中有少量铜、钴,矿石中铜钴元素赋存状态极其复杂.最佳的浸出条件为粒度小于74μm的矿粒所占比例70%、浸出温度65℃、浸出时间4 h、矿浆质量分数30%、硫酸加入量55 kg·t-1.该条件下铜浸出率可达74.34%左右,钴浸出率可达43.32%左右.充分利用萃余液中的硫酸可降低酸耗,硫酸用量减少20%以上.在搅拌浸出过程中加入适量还原剂Na_2SO_3或FeSO_4,可将钴的浸出率从43%提高到78%.     

FH-92结合剂中固化剂的研制及应用

研制的是 FH-92结合剂中的磷酸质固化剂。这种固化剂具有在一定 pH 值的碱性溶液中均匀地释放磷酸的性质,这种性质可写为 Y=AX+B.这里 X 代表时间间隔,Y 代表时间间隔 X 内固化剂中释放的磷酸的量。这种结合剂可较好地适用于高温修补炉衬和不用预先烧制的耐火物。     

Linking leach chemistry and microbiology of low-grade copper ore bioleaching at different temperatures

The effects of temperature on chalcocite/pyrite oxidation and the microbial population in the bioleaching columns of a low-grade chalcocite ore were investigated in this study. Raffinate from the industrial bioleaching heap was used as an irrigation solution for columns operated at 20, 30, 45, and 60℃. The dissolution of copper and iron were investigated during the bioleaching processes, and the microbial community was revealed by using a high-throughput sequencing method. The genera of Ferroplasma, Acidithiobacillus, Leptospirillum, Acidiplasma, and Sulfobacillus dominated the microbial community, and the column at a higher temperature favored the growth of moderate thermophiles. Even though microbial abundance and activity were highest at 30℃, the column at a higher temperature achieved a much higher Cu leaching efficiency and recovery, which suggested that the promotion of chemical oxidation by elevated temperature dominated the dissolution of Cu. The highest pyrite oxidation percentage was detected at 45℃. Higher temperature resulted in precipitation of jarosite in columns, especially at 60℃. The results gave implications to the optimization of heap bioleaching of secondary copper sulfide in both enhanced chalcocite leaching and acid/iron balance, from the perspective of leaching temperature and affected microbial community and activity.     

Use of mesophilic and thermophilic bacteria for the improvement of copper extraction from a low-grade ore

Bioleaching was examined for copper extraction from a low grade ore using mesophilic and moderate thermophilic bacteria. Five equal size columns were used for the leaching of the ore. Sulfuric acid solution with a flow rate of 3.12 L·m-2·h-1 and pH 1.5 passed through each column continuously for 90 d. In the first and the second column, bioleaching was performed without agglomeration of the ore and on the agglomerated ore, respectively. 28wt% of the copper was extracted in the first column after 40 d, while this figure was 38wt% in the second column. After 90 d, however, the overall extractions were almost the same for both of them. Bioleaching with mesophilic bacteria was performed in the third column without agglomeration of the ore and in the fourth column on the agglomerated ore. After 40 d, copper extractions in the third and the fourth columns were 62wt% and 70wt%, respectively. Copper extractions were 75wt% for both the columns after 90 d. For the last column, bioleaching was performed with moderate thermophilic bacteria and agglomerated ore. Copper extractions were 80wt% and 85wt% after 40 and 90 d, respectively. It was concluded that crushing and agglomeration of the ore using bacteria could enhance the copper extraction considerably.     

Thin-layer heap bioleaching of copper flotation tailings containing high levels of fine grains and microbial community succession analysis

Thin-layer heap bioleaching of copper flotation tailings containing high levels of fine grains was carried out by mixed cultures on a small scale over a period of 210 d. Lump ores as a framework were loaded at the bottom of the ore heap. The overall copper leaching rates of tailings and lump ores were 57.10wt% and 65.52wt%, respectively. The dynamic shifts of microbial community structures about attached microorganisms were determined using the Illumina MiSeq sequencing platform based on 16S rRNA amplification strategy. The results indicated that chemolithotrophic genera Acidithiobacillus and Leptospirillum were always detected and dominated the microbial community in the initial and middle stages of the heap bioleaching process; both genera might be responsible for improving the copper extraction. However, Thermogymnomonas and Ferroplasma increased gradually in the final stage. Moreover, the effects of various physicochemical parameters and microbial community shifts on the leaching efficiency were further investigated and these associations provided some important clues for facilitating the effective application of bioleaching.     

基于原子力显微镜的沥青再生机理

沥青的老化严重影响了沥青混合料在实际应用中的耐久性,为了研究沥青的老化和再生机理,将基质沥青进行SHRP(strategic highway research program)老化,利用原子力显微镜(atomic force microscope, AFM)和动态剪切流变仪(dynamic shear rheometer, DSR)技术研究不同掺量的基质沥青和再生剂对老化沥青的再生效果。结果表明:基质沥青和再生剂均能对老化沥青产生再生效果,且随着它们掺量的增大,再生效果变好;老化沥青表面微观结构粗糙不均匀,基质沥青和再生剂的加入有效改善其表面微观形貌,降低其黏附力和粗糙度指标,同时使老化沥青相位角增大、复数剪切模量和抗车辙因子减小;温度的升高有助于再生剂在老化沥青中的扩散。可见再生剂的主要再生机理是增加并扩散老化沥青中缺失的组分。     

矿石粒径对矿堆内溶液毛细渗流的影响特征

为探究矿石粒径对矿堆内溶液毛细渗流的影响特征,利用所构建的溶液毛细上升实验装置,针对单一粒径矿堆和混合粒径矿堆,分别开展不同矿石粒径下溶液毛细上升实验,得到了溶液毛细上升高度与时间的关系曲线及相应的拟合方程,分析了溶液上升速度随时间变化规律。研究发现：实验初期矿堆内溶液上升速度较快,随着实验时间的增加,溶液上升速度逐渐减小并最终降为零,且溶液最大上升高度及溶液上升速度均与矿石粒径负相关。矿堆内由毛细作用形成的不可动溶液含量随矿石平均粒径的减小而增大,细颗粒矿石含量过多时在矿堆内将形成大范围的不可动溶液区域,影响矿堆内溶液渗透效果。     

Extracting copper from copper oxide ore by a zwitterionic reagent and dissolution kinetics

Sulfamic acid (SA), which possesses a zwitterionic structure, was applied as a leaching reagent for the first time for extracting copper from copper oxide ore. The effects of reaction time, temperature, particle size, reagent concentration, and stirring speed on this leaching were studied. The dissolution kinetics of malachite was illustrated with a three-dimensional diffusion model. A novel leaching effect of SA on malachite was eventually demonstrated. The leaching rate increased with decreasing particle size and increasing concentration, reaction temperature and stirring speed. The activation energy for SA leaching malachite was 33.23 kJ/mol. Furthermore, the effectiveness of SA as a new reagent for extracting copper from copper oxide ore was confirmed by experiment. This approach may provide a solution suitable for subsequent electrowinning. In addition, results reported herein may provide basic data that enable the leaching of other carbonate minerals of copper, zinc, cobalt and so on in an SA system.