生物挂膜填料对某铀矿浸铀菌群的影响

微生物堆浸是利用微生物的生物化学作用,选择性地将被浸矿物或其他有用矿物从矿石中浸出来的一种方法,这种方法简便,生产周期短,成本低,利用率高,减少对环境所造成的不利影响等优点。为满足微生物堆浸对细菌的需求,对细菌生长周期、活性等提出了一定的要求,在文章中,笔者讨论以及分析了两种不同的生物挂膜填料选择对该铀矿中浸铀菌群的影响。结果表明,有填料比无填料对细菌的生长更有利,不同填料对细菌的生长效果影响不同。     

某铀矿矿石品位变化同堆浸氧化剂(二氧化锰)加入量关系研究简

铀矿山采用堆浸方法处理铀矿石时,氧化剂加入量对铀浸出效果有重要影响.因此当铀矿矿石岩性发生变化,其堆浸氧化剂加入量也需要作相应的调整.解决好氧化剂加入量和矿石品位变化关系对提高铀矿山湿法冶金回收率和矿山经济效益具有重要意义.通过对某铀矿水冶工艺车间的工艺流程分析发现,该铀矿目前生产工艺中氧化剂（Mn02）加入量没有结合铀矿石岩性变化,尤其是矿石品位变化.理论计算的氧化剂加入量和长期采用固定加入量存在很大差异,造成了氧化剂的浪费.该铀矿山酸法堆浸氧化剂加入量应作相关研究给予调整,氧化剂加入量调整对矿区节能减排提高经济效益具有重要实际意义.     

国内外铀矿石生物浸出机理及工艺应用研究现状

微生物对铀矿的浸出主要以间接作用为主,Fe2+是铀矿氧化反应的电子传递者.生物浸出铀可以减少酸用量,提供硫酸高铁代替双氧水或过氧硫酸(盐)等氧化剂,可用于多种不同的浸出方式中,强化浸出过程,改善铀浸出动力学,提高铀浸出率,有利于环境保护.铀的生物浸出工艺主要有:生物堆浸工艺、生物地浸工艺和生物槽浸工艺.     

微生物浸铀研究进展

论述了微生物浸铀原理,以及菌群生长的影响因素,根据矿石特性对细菌进行驯化。探讨矿石性质、粒径、矿浆浓度等对浸出的影响,总结了铀矿石预处理以强化微生物浸铀方法。概述微生物原位地浸低品位铀的工业应用。     

广西某铀矿流出物和周围水体放射性水平现状监测及评价

铀矿石中可提取到镭、铀和其他稀土元素,广西的铀矿资源较为丰富,被核工业称为“开业之石”的新中国第一块铀矿既产自广西贺州市。某放射性铀矿开采和水冶企业位于广西境内的车田乡与瓜里乡交界地带的沙子江,该矿项目已于2016年停产,矿井口封闭并处于淹井状态,堆浸及水冶也全面停止,但以废水处理为主的环保设施仍维持运行正常。对该铀矿停产后进行长期水体和流出物放射性监测,发现水中各监测断面的各类放射性核素活度浓度在历年涨落范围内,各放射性指标符合相关行业标准,可初步分析停产后环保设施运行情况是否正常,初步判断停产后矿区对周围水体是否存在放射性影响。     

浸铀细菌扩大培养过程中沉淀物组分研究

堆浸是从低品位矿石中回收金属的一种简便、经济的技术。在745铀矿厂进行的微生物堆浸实验中,发现在微生物培养中有大量沉淀物质产生。在文章中,笔者讨论以及分析了在不同酸度下微生物的沉淀物质。得出菌液扩大培养中所产生沉淀元素除了来自培养菌液的Fe还有来自矿堆的S、Ca、Ti等元素。含量最多的沉淀矿物是铁化合物沉淀和钙化合物沉淀。     

高酸酸化在某铀矿石堆浸中的试验研究

铀矿堆浸常用硫酸作为浸出剂,浸出初期因生成化学沉淀造成结垢堵塞现象时常发生,严重的结垢会导致堆浸无法正常进行。从矿堆开始加入浸出剂到浸出液p H〈2.5的这一时期称为矿堆的酸化期。浸出剂的酸浓度对酸化时间、总浸出时间和浸出效果有一定的影响。简述堆浸中因化学沉淀形成结垢的原因,研究酸浓度对某铀矿石浸出的影响,提出了高酸酸化的建议,对生产和科研具有一定的参考价值。     

引入铀矿细菌浸出工艺实现水冶单一型向混合型转变的可行性研究

相山铀矿田矿石元素组合有多种类型,铀-多元素矿化的空间分布具有明显的规律,根据矿性的不同,水冶由单一型向混合型转变,是多矿山单水冶厂型铀矿企业将来的发展趋势。通过研究不同浸出工艺自身的优缺点,经过合理搭配可以彼此之间互补,从而提高矿石浸出率、降低化工原材料的损耗,有效的控制水冶成本。在多金属的硫化矿床中,通常含有黄铁矿（Fe S2）,在有细菌的条件下,细菌将亚铁氧化为三价铁,硫氧化为硫酸,其中三价铁是一种很有效的矿物氧化剂和浸出剂,所以引入铀矿细菌浸出工艺,可完善水冶混合型工艺,降低酸耗。通过试验表明细菌浸出在实际生产中的可行性,根据试验结果,再对实际生产中细菌浸出存在的问题提出建议,通过工艺互补,从而达到最佳生产方案。混合型水冶的建立目前仍然受很多因素的制约,如何解决制约因素、合理分配、调节工艺参数等问题需进一步探讨解决。     

微生物浸铀过程中的群落分析研究

堆浸生产是一个开放系统,矿石与周围的环境密切接触,由于环境中的微生物比较复杂,这样就会使得堆浸系统的群落变化更为复杂。浸矿体系中的菌群结构及其演替规律与浸出率具有密切的关系,探索浸矿体系中细菌的种群结构及其演替,对优化浸出体系菌群组成,提高浸出率具有指导作用。     

高酸强化堆浸技术在某铀矿中的应用

介绍高酸强化堆浸技术在某铀矿中的应用情况.先后从高酸强化浸出方法的主要技术、在某铀矿工业试验、应用效果以及高酸强化浸出问题与讨论这四个方面进行论述,得出高酸熟化堆浸技术在某铀矿堆浸生产中取得较好的成果.     

An investigation into the dynamics of chalcopyrite bioleaching

A study was undertaken to investigate the dynamics of chalcopyrite bioleaching. The analysis revealed significant dynamics features because the chemical leaching rate of chalcopyrite does not vary monotonically with solution redox potential but undergoes a maximum followed by a minimum as potential increases. The analysis does account for reaction passivation, an effect that has consistently been reported in the literature. The existence and stability of steady states were determined as functions of the solution redox potential, reactor temperature, and biomass concentration. It was found that the rate of bioleaching increased with temperature at lower overall solution potentials with competitive rates observed at high ferric/ferrous ion ratios. Both high and low overall bioleaching rates were observed with increasing biomass concentration, indicating an upper concentration limit before passivation. These results indicate that the frequently observed inhibiting rates may simply be artifacts of the system dynamics rather than due to physical phenomena. © 2010 American Institute of Chemical Engineers AIChE J, 2010     

铁闪锌矿细菌浸出过程中亚铁和细菌初始浓度的影响

利用摇瓶浸出研究了氧化亚铁硫杆菌在35℃下生物浸出铁闪锌矿的过程,探讨了铁含量和细菌接种量等因素对细菌在矿浆中的生长以及对锌浸出的影响,并对细菌浸出铁闪锌矿的机理进行了分析. 发现在不添加铁的情况下,即使细菌接种量达到40 mL,矿浆的氧化还原电位提高仍然非常缓慢,细菌无法在矿浆中正常生长,证明不存在直接浸出;而在添加FeSO4×7H2O的矿浆中,随接种量的增加细菌浸出铁闪锌矿的速度加快. 结果表明,铁闪锌矿的浸出需要一定量的Fe3+作为氧化浸出剂以提高浸出速度,因此必须预先添加部分Fe2+作为细菌氧化生成Fe3+的来源. 通过分析浸出过程中矿浆Eh和铁浓度的变化,认为Eh的高低与细菌浸出速度直接相关. 并且根据实验和电镜分析证明氧化亚铁浸出铁闪锌矿的过程是pH值上升的耗酸过程.     

Recovery of uranium from low-grade ore using microorganism isolated from uraniferous rock sample

Bioleaching, in the scope of biotechnology, is one of the promising technologies, which can be utilized for extracting valuable radioactive metal (uranium) from other radioactive ones. Also, it considered as an economical way to recover uranium from low-grade ores after the depletion of high grade uranium deposits. The aim of the work is to explore the formation and composition of the bioprecipitate from low-grade uraniferous rock sample through the bioleaching process using fungi. Furthermore, to identify the radionuclides distribution during work stages using the Hyper Pure Germanium detector. The results showed that; Aspergillus niger accomplished 71.4% of uranium recovery, as well as, formation of stable organo-uranyl complex. The obtained bioprecipitate, composed of ″uranyl acetate hydrate,″ asserted that the uranium is nearly free from other radionuclides present in the original sample without any subsequent purification processes, whereas could not achieved by the conventional process of uranium recovery.     

绿色化制备硫酸铁铵条件的探讨

用铁粉和稀硫酸反应制备硫酸亚铁,再用双氧水作氧化剂、铁氰化钾作指示剂制备硫酸铁,最后加入饱和硫酸铵,经过蒸发、冷却、结晶、抽滤制得硫酸铁铵产品。确定了硫酸浓度为3 mol/L,搅拌速度为870 r/min,制备硫酸亚铁反应温度为95℃,制备硫酸铁铵反应温度为45℃和制备硫酸铁铵溶液酸度为pH≤0.5的最佳条件。     

固定床生物反应器模拟溶浸采铀吸附尾液中Fe2+的氧化试验

以活性炭作载体固定嗜酸氧化亚铁硫杆菌,构建固定床生物反应器,模拟溶浸采铀矿山吸附尾液全Fe浓度和溶液pH条件,对生物反应器氧化Fe²⁺工艺参数进行了试验研究。结果表明:活性炭作载体比无载体时生物反应器氧化Fe²⁺速率增加了1.4倍,由0.5 g·L^-1·h^-1增大至1.2 g·L^-1·h^-1;生物反应器运行过程中溶液中全Fe因生成铁钒而不断消耗,需要定期清理反应器中的铁矾和补充FeSO₄以保持溶液中全Fe浓度;生物反应器最优的操作条件是:底部通气,Fe²⁺浓度为5 g·L^-1时,溶液流量为1.2~1.4 L·h^-1;Fe²⁺浓度为1 g·L^-1时,溶液流量为5.4 L·h^-1。     

Recovery of Uranium from Seawater: A Review of Current Status and Future Research Needs

The recovery of uranium (U) from seawater has been investigated for over six decades in efforts to secure uranium sources for future energy production. The majority of the research activities have focused on inorganic materials, chelating polymers, and nanomaterials. Previous studies of uranium adsorption from aqueous solutions, mainly seawater, are reviewed here with a focus on various adsorbent materials, adsorption parameters, adsorption characterization, and marine studies. Continuous progress has been made over several decades, with adsorbent loadings approaching 3.2 mg U/g adsorbent in equilibrium with seawater. Further research is needed to improve first, the viability including improved capacity, selectivity, and kinetics, and second, the sorbent regeneration for multicycle use. An overview of the status of the uranium adsorption technology is provided and future research needs to make this technology commercially competitive are discussed.     

分光光度法在玄武岩纤维中铁化合价态检测的应用分析

在玄武岩纤维中,以两种化合价态存在的铁氧化物质量分数及相对含量对纤维热稳定性、耐候性和化学稳定性影响显著。介绍采用邻二氮杂菲分光光度法测量玄武岩纤维中二价铁含量的方法,并用盐酸羟胺还原后标定总铁含量,有效测量玄武岩纤维中Fe~(2+)和Fe~(3+)含量。通过对测试结果准确性的分析,探讨了可能产生的测试误差。经过测试发现,利用此法分析玄武岩纤维中以两种价态存在的铁氧化物准确性较好,测试结果可靠性用简单的数学分析加以说明。     

黑曲霉产有机酸浸出铀矿石的影响因素

为了解培养基种类、培养温度和pH值等因素对黑曲霉产生的混合有机酸浸出铀矿石的影响,从铀矿山水样中分离、纯化得到了一株真菌--黑曲霉,应用马铃薯-蔗糖培养基（potato sucrose agar,PSA）和葡萄糖-玉米浆培养基(dextrose corn syrup,PCS)进行黑曲霉培养,获得了不同培养温度下产生的pH值不同的黑曲霉产混合有机酸,并将之作为浸出剂用于浸铀实验研究。研究表明,黑曲霉产生的有机酸的主要组分为草酸和柠檬酸等有机酸,培养基种类的不同会影响黑曲霉所产有机酸的浸铀效果,采用PSA培养基培养的黑曲霉产生的有机酸浸铀效果更好（p<0.05）。培养温度和混合有机酸的pH值也会对黑曲霉代谢产物的铀浸出率有显著性影响（p<0.05）,且二者具有交互效应,pH值对铀浸出率的影响相对较大。应用PSA培养基时,最佳培养温度为25℃,最佳代谢产物pH值为2.3;应用PCS培养基时,最佳培养温度为30℃,最佳混合有机酸pH值为2.0。培养基种类、温度和pH值主要通过改变黑曲霉产生的有机酸的成分和含量对铀浸出率产生影响。     

Modelling a uranium ore bioleaching process

A dynamic simulation model for the bioleaching of uranium ore in a stope leaching process has been developed. The model incorporates design and operating conditions, reaction kinetics enhanced by Thiobacillus ferrooxidans present in the leaching solution and transport properties. Model predictions agree well with experimental data with an average deviation of about ± 3%. The model is sensitive to small errors in the estimates of fragment size and ore grade. Because accurate estimates are difficult to obtain a parameter estimation approach was developed to update the value of fragment size and ore grade using on-line plant information.     

Distribution of uranium in the production of triple superphosphate (TSP) fertilizer and phosphoric acid

In this study the distribution of uranium, which is one of the radioactive elements present in phosphate fertilizers was investigated in different steps of the triple superphosphate (TSP) production process. The uranium in phosphate rock, phosphoric acid, phosphogypsum and TSP was extracted into the organic phase by using the TOPO extraction method. The uranium contents of these materials were determined by measuring the absorbance of the formed (pH 7.6) uranyl bromo-PADAP [uranyl(2-(5-bromo-2-pyridylazo)-5-diethylaminophenol)] complex solutions at 574 nm against blank. It was found that 50% of the uranium is dissolved in the acid during the production of phosphoric acid while the remainder is precipitated with phosphogypsum residue. The observations showed that in the second step, the sum of uranium in phosphate rock and phosphoric acid completely passed into TSP in the TSP manufacturing process.