Influence of impeller diameter on overall gas dispersion properties in a sparged multi-impeller stirred tank

The impeller configuration with a six parabolic blade disk turbine below two down-pumping hydrofoil propellers, identified as PDT + 2CBY, was used in this study. The effect of the impeller diameter D, ranging from0.30 T to 0.40T(T as the tank diameter), on gas dispersion in a stirred tank of 0.48 m diameter was investigated by experimental and CFD simulation methods. Power consumption and total gas holdup were measured for the same impeller configuration PDT + 2CBY with four different D/T. Results show that with D/T increases from 0.30 to 0.40, the relative power demand(RPD) in a gas–liquid system decreases slightly. At low superficial gas velocity VSof 0.0078 m·s-1, the gas holdup increases evidently with the increase of D/T. However, at high superficial gas velocity, the system with D/T = 0.33 gets a good balance between the gas recirculation and liquid shearing rate, which resulted in the highest gas holdup among four different D/T. CFD simulation based on the two-fluid model along with the Population Balance Model(PBM) was used to investigate the effect of impeller diameter on the gas dispersion. The power consumption and total gas holdup predicted by CFD simulation were in reasonable agreement with the experimental data.

An innovative flake graphite upgrading process based on HPGR,stirred grinding mill, and nanobubble column flotation

Physical upgrading of graphite is typically achieved with many stages of grinding and flotation to produce a concentrate with approximately 95% carbon grade.An innovative grinding and column flotation process has been developed for efficient graphite upgrading to substantially simplify the process flowsheet and reduce operating costs.In this process,a high-pressure grinding roller(HPGR) and a stirred mill were employed as primary comminution techniques and a nanobubble flotation column as a key separation process.The results obtained with a crystalline flake graphite sample with a carbon grade of 11.15% show that the novel process can produce a concentrate with 94.82% carbon grade and 97.89% recovery from an open circuit of one rougher and two cleaner flotation stages.Scanning electron microscope(SEM)microphotographs indicate that HPGR offers the advantage of more effective protection of graphite flakes during crushing.Grinding test results show that stirred mill could not only protect graphite flakes but also promote the efficient liberation of graphite.Compared with the traditional flotation process,nanobubble flotation can effectively recover ultrafine graphite.The new process possesses a number of important advantages over the traditional method,including substantially higher graphite recovery,greatly simplified process flowsheet,better protection of flake size,reduced reagent consumption and process costs,etc.

The Resident Time Distribution of Injected Dispersed Drops in Stirred Extraction Columns

A resident time model is proposed to evaluate the performance of agitated extraction columns. In this model, the resident time of dispersed drops is simulated with the discrete phase modeling, where the continuous phase and the dispersed phase （drops） are described by the single-phase Navier-Stokes （turbulence） model and Lagrangian model, respectively. The interaction of dispersed phase and continuous phase is neglected for the low concentration of drop in the cases studied. The statistical parameters of drops （the average resident time and standard deviation） under different operation conditions are computed for four columns. The relation of the above statistical parameters with the performance of columns is discussed and the criterions for an optimal compartment are outlined. Our results indicate that the resident time model is useful to evaluate the performance and optimize the design of extraction columns.

The Operating Performance of Stirred Column Reactor

A theoretical analysis of the effects of flow and mixing on the operating features of astirred column reactor(SCR)with multistage mixers and cooling partition plates was conducted.Amethod for calculating the concentration reduction for a second order chemical reaction in a SCRwas proposed.The reactants concerned were pre-mixed before feeding into the SCR.The SCR wascomposed of a number of stages with interstage backmixing.Experimental investigation with variousreaction media were carried out in order to study the effect of mixing on the operational performanceof the SCR.The experimental data were compared with the theoretical results.

不同深度离子型稀土矿连续浸出实验

这是一篇冶金工程领域的论文。以赣州地区某离子型稀土矿为研究对象,采用连续搅拌浸出和柱浸的方式,研究不同条件下矿样中稀土及杂质元素的浸出情况,为离子型稀土矿产资源的绿色高效开采提供参考。实验结果表明:连续搅拌浸出过程中稀土浸出率均在80%左右,二次浸出液中TREO/Al明显增大,TREO/Ca明显减小,TREO/Mg略微减小;柱浸实验中随着浸矿深度的增加,浸出液pH值逐步上升,TREO/Al增加至15.52,TREO/Ca降低至0.64。稀土浸出率均达到96%以上,但随着深度的增加轻稀土配分由49.43%上升到了53.28%,重稀土配分从35.91%逐步下降至32.18%。连续搅拌浸出和柱浸实验均表明随着矿样深度的增加,稀土浸出率无明显降低,低品位矿层稀土浸出仍然具有一定的可行性。

玉龙铜矿氧化矿石合理浸出工艺研究

对西藏玉龙铜矿氧化带矿石进行全粒级柱浸和洗矿—矿砂柱浸—矿泥搅拌浸出试验,结果表明:全粒级柱浸时矿石渗透性差,提高滴林强度易出现积液现象,难以顺利浸出;洗矿后矿砂的渗透性能好,可使柱浸铜浸出率达到78%以上,同时矿泥搅拌浸出的铜浸出率可达96%以上。根据试验结果,认为洗矿—矿砂堆浸—矿泥搅拌浸出是处理玉龙铜矿氧化带矿石的合理工艺。

共轭二烯烃溶液聚合连续搅拌塔式反应器的研究——流动模型

针对可用于共轭二烯烃溶液聚合的连续搅拌塔式反应器的宏观流动过程进行了研究,提出了“多级、级际有限混和、伴有死区和级际旁路”的流动模型,证明并得到了模型参数与停留时间分布的矩之间的函数关系,给出了确定模型参数的过程和实例。研究结果表明,提出的多参数流动模型和模型参数的确定方法对研究连续搅拌塔式反应器的流动模式具有指导意义。

某离子型稀土矿浸出试验

以中国南方地区某离子型稀土矿为研究对象,采用搅拌浸出和柱浸的方式,研究不同条件下矿样中稀土及杂质元素的浸出情况,为离子型稀土矿产资源的绿色高效开采提供参考。结果表明,浸出液固比对离子相稀土浸出率影响较大,浸出时间影响较小,离子相稀土浸出过程时间短,反应迅速;柱浸过程中离子相稀土流出速率最快,达到平衡时间短,杂质元素前期浸出浓度高,后续拖尾严重;离子相稀土浸出率随着样品深度的增加不断降低,符合南方离子型稀土成矿规律;硫酸铵浸出过程中铵根离子损失量较大,最低损失率超过11.31%,硫酸根不参与金属离子的交换反应过程,回收率最高可达99.22%。

新型连续乳液聚合反应器

介绍了4种主要连续乳液聚合反应器的研究新进展,包括连续搅拌釜式反应器、连续环管式反应器、脉冲填料塔式反应器及库爱特-泰勒旋流式反应器。提出了连续乳液聚合反应器的发展方向。

搅拌塔式反应器传热特性研究

分析了搅拌塔式反应器（ＳＣＲ）中多级冷却盘管隔板的传热特性，用稳态和非稳态的传热方法进行了实验研究。提出了同时考虑搅拌雷诺数和轴向液流雷诺数影响的ＳＣＲ中多级冷却盘管隔板表面传热膜系数的关联式。研究结果表明，对于ＳＣＲ中冷却盘管隔板表面的传热膜系数，轴向液流雷诺数的影响与搅拌雷诺数的影响相比具有同等的重要性。

中药饮片中真菌毒素前处理方法进展

中药真菌毒素是真菌在中药中所产生的次生代谢产物,一般不表现出急性毒性,但具有较强的蓄积性。我国常用中药存在真菌毒素污染或潜在污染的情况。为了改善中药基质对真菌毒素检测结果的影响,提高中药真菌毒素检测灵敏度与准确度,保证人类健康,减少真菌毒素带来的经济损失,本文对现代中药真菌毒素提取和净化方法进行了总结和概括,主要包括高速均质提取、搅拌提取、超声提取、振荡提取及免疫亲和柱净化法、固相萃取柱净化法、QuEChERS净化法等,并对真菌毒素前处理方法进行展望,以供国内外同行参考借鉴。

XJM-S系列浮选机研究现状及应用

介绍了我国煤炭行业现行使用的各类浮选设备,包括选煤厂引进的国外浮选机和我国自主研发浮选机,广泛应用于各大选煤厂的喷射式浮选机、浮选柱、微泡浮选机和机械搅拌式浮选机。分析了各类型浮选设备的工作原理和结构特点,提出了我国煤泥浮选设备的发展方向和趋势。

CaO添加顺序对废弃泥浆絮凝效果的影响

针对温州某钻孔灌注桩废弃泥浆进行了沉降柱试验和颗粒分析实验,研究有机絮凝剂APAM以及无机絮凝剂CaO对泥浆沉降性能和颗粒粒径的影响,着重探究了无机絮凝剂CaO的不同添加顺序对有机絮凝剂APAM絮凝效果的影响。结果表明:在较少APAM添加量(10mL)下后添加CaO能增大泥浆的初始沉降量;先添加CaO再添加APAM,不利于APAM絮凝作用的发挥;后添加CaO的情况下,CaO对于最终的絮体粒径的影响主要取决于絮体本身的强度及搅拌强度。

对二甲苯氧化鼓泡反应器性能研究

对内径786mm，高3000mm的2种环管开孔率进气的PX氧化鼓泡反应器的性能进行了研究。实验结果表明。该反应器接近全混流，固体颗粒在反应器内悬浮均匀．锚桨搅拌转速以n=8-19r／min为佳，侧线进气以下侧线5％。10％比例为宜，开孔率0.842％环管分布器气含率高于开孔率0．647％环管分布器气古率。固体颗粒存在会导致气古率降低，并得到可应用于工业PX氧化反应器的设计和放大带下侧线的气含率关联式。

STUDY ON BIOLEACHING OF PRIMARY CHALCOPYRITE ORE WITH THERMOACIDOPHLIC ARCHAE

A high temperature-tolerating thermoacidophilic archae （TA） was isolated from water samples collected from a hot sulfur-containing spring in the Yunnan Province, China, and was used in bioleaching experiments of a low-grade chalcopyrite ore. The TA grow at temperatures ranging from 40 to 80℃, with 65℃ being the optimum temperature, and at pH values of l.5 to 4.0, with an optimum pH value of 2.0. The bioleaching experiments of the chalcvpyrite ore were conducted in both laboratory batch bioreactors and leaching columns. The results obtained from the bioreactor experiments showed that the TA bioleaching rate of copper reached 97% for a 12-day leaching period, while the bioleaching rate was 32.43% for thiobacillus ferrooxidans （Tf） leaching for the same leaching time. In the case of column leaching, tests of a two-phase leaching （196 days）, that is, a two-month （56 days） Tf leaching in the first phase, followed by a 140-day TA leaching in the second phase were performed. The average leaching rate of copper achieved for the 140-day TA leaching was 195mg/（L.d）, while for the control experiments, it was as low as 78mg/（L .d） for the Tf leaching, indicating that the TA possesses a more powerful oxidizing ability to the chalcopyrite than Tf Therefore, it is suggested that the two-phase leaching process be applied to .for the heap leaching operations, whereas, the TA can be used in the second phase when the temperature inside the heap has increased, and the primary copper sulfide minerals have already been partially oxidized with Tf beforehand in the first phase.

对选矿流程中搅拌旋流器的探讨

论述了传统水力旋流器的优缺点及工作参数,详细介绍了旋流器运行产生的空气柱效应,并提出通过改进搅拌旋流器设备结构和调整性能参数,能提高分级和工作效率,减少矿物过粉碎和流程返砂量,提高设备使用寿命,降低投资风险和维护费用,极大地节约运营成本。

新钢业炼钢厂KR法铁水脱硫搅拌装置改造

攀钢(集团)西昌新钢业有限公司炼钢厂,于2007年建成一套60t铁水罐KR法铁水脱硫搅拌装置,该装置建成后,设备故障不断,设计制造厂家现场安装调试人员不能解决。为使该装置尽快投用,新钢业炼钢厂等部门技术人员联合攻关,通过对设计缺陷逐一分析,对该铁水搅拌装置和升降小车升降机构进行了彻底改造,最终取得较好使用效果。

津巴布韦Three Cheers金矿石选矿试验研究

津巴布韦ThreeCheers地表氧化型金矿石(金品位1.94 g/t)磨至-200目95%情况下进行全泥氰化浸出,在矿浆pH=11~12,氰化钠浓度分别为0.10%、0.20%、0.25%,调节搅拌器转速为300 r/min,浸出温度为15~25℃,浸出时间为24 h情况下的金浸出率分别为94.85%、95.88%、96.91%;粒度为20~0、15~0、10~0 mm的矿石渗滤氰化柱浸25 d,浸出率分别为66.08%、70.03%、70.36%,第26天的浸渣金品位分别为0.60、0.49、0.47 g/t,按浸渣金品位计算的金浸出率分别为67.58%、74.74%、75.77%,从节能减排角度确定的适宜浸出粒度为15~0 mm。项目将按堆浸工艺还是全泥浸出工艺进行建设,必须结合投资、效益、尾渣处理等因素来考虑。

浮选柱选精煤工艺系统的改进

为提高浮选精煤的分选精度和分选效率 ,对搅拌系统、旋流力场和喷淋装置等进行了改进 ,使物料搅拌均匀度达到 90 %以上 ,精煤灰分下降了 1.5 %～ 2 .0 % ,分选效率达到 90 %以上 。

柱前衍生化RP-HPLC法鉴别及测定9种补气药中的生物胺

目的:建立柱前衍生化RP-HPLC法测定白术、人参、红参、西洋参、党参、炒扁豆、刺五加、绞股蓝、红景天中11个生物胺的方法,并探讨与补气的相关性。方法:药材样品经1 mol·L^(-1)盐酸提取,正丁醇-二氯甲烷(1∶1)萃取富集,以丹磺酰氯为柱前衍生试剂进行衍生化,RP-HPLC法测定。采用C18色谱柱(200 mm×4.6 mm,5μm),以乙腈(A)-水(B)为流动相,梯度洗脱(0~7 min,45%A→50%A;7~25 min,50%A→90%A;25~35 min,90%A;35~40 min,90%A→45%A),流速为0.8 mL·min^(-1),检测波长为254 nm,柱温为30℃。结果:甲胺、尸胺、组胺、亚精胺与精胺的线性范围为0.10~10.00 mg·L-1(r>0.999),色胺、腐胺的线性范围为0.10~50.00 mg·L-1(r>0.999),2-苯乙胺、5-羟色胺、酪胺与多巴胺的线性范围为0.25~10.00 mg·L-1(r>0.999),平均回收率在70.4%~96.3%之间。白术、党参、炒扁豆中均含有甲胺、腐胺、尸胺、亚精胺与精胺,人参、刺五加中均含有腐胺、尸胺、亚精胺与精胺,红参中含有腐胺、亚精胺与精胺,西洋参中含有腐胺、尸胺、组胺、亚精胺与精胺,绞股蓝中含有甲胺、腐胺、尸胺、酪胺、亚精胺与精胺,红景天中含有甲胺、腐胺与亚精胺。结论:在白术、人参、红参、西洋参、党参、炒扁豆、刺五加、绞股蓝、红景天中含有生物胺类成分。亚精胺是这些补气药中的共有成分,考虑到它的生物活性,这可能是中药补气和抗衰老延年益寿作用的关键成分之一。