Study on the Acute Toxicity of Rare Earth Yttrium to Earthworms under the Stress of Leaching Agent Ammonium Sulfate

This study aimed to investigate the toxicity of rare earth ion yttrium under the stress of leaching agent ammonium sulfate （NH4）2SO4. [Method] By using earthworms as indicator organisms of environmental pol ution, acute toxic ef-fects of rare earth yttrium on earthworms under the stress of ammonium sulfate were investigated with filter paper contact method. [Result] Under single stress of rare earth yttrium, the semi-lethal concentration after 48 and 24 h was LC50=213.41 mg/L and LC50=322.63 mg/L, respectively. ② Under single stress of ammonium sul-fate, the semi-lethal concentration after 48 h and 24 h was LC50=13.89 g/L and LC50=15.05 g/L, respectively. ③ In combined treatment of low concentration （10 g/L） of ammonium sulfate and different doses of rare earth yttrium, the semi-lethal con-centration after 48 and 24 h was LC50=198.65 g/L and LC50=399.85 g/L, respective-ly; in combined treatment of middle concentration （14 g/L） of ammonium sulfate and different doses of rare earth yttrium, the semi-lethal concentration after 48 and 24 h was LC50=167.3 mg/L and LC50=256.73 mg/L, respectively; in combined treatment of high concentration （20 g/L） of ammonium sulfate and different doses of rare earth yttrium, the semi-lethal concentration after 48 h and 24 h was LC50=31.03 mg/L and LC50=127.65 mg/L, respectively. [Conclusion] Low concentration of ammonium sulfate could reduce the toxicity of rare earth yttrium to earthworms and produce certain antagonism against rare earth yttrium; middle concentration ammonium sulfate in-creased the toxicity of rare earth yttrium to earthworms and produced relatively sig-nificant synergistic effects; high concentration ammonium sulfate significantly in-creased the toxicity of rare earth yttrium to earthworms. Compared with ammonium sulfate, dead earthworms exposed to rare earth yttrium were more easily fractured, and living earthworms showed insensitive response to acupuncture.

Lithium Recovery from Electrodes in Cellphone Batteries through the Leaching Process with Organic Agents Assisted by Ultrasound

The present work proposes a mean for recovery of metals used in current ion-lithium batteries, like lithium, cobalt and nickel, using organic agents and ultrasound instead of the more aggressive and less environment friendly method with sulfuric acid. This is especially useful in those countries that doesn’t have lithium deposits and have a growing demand of such batteries, reducing the economic loss this represents. During the process, variables such as temperature, leaching agent concentration and ultrasound frequency were modified, using concentrations of 0.5 M (molar), 1 M and 1.5 M of sodium citrate, temperatures of 25°C, 55°C and 60°C and also ultrasound frequencies of 20 KHz, 30 KHz and 40 KHz. It was found that the best combination of these variables that yielded the most quantity of the desired metal was 0.5 M concentration for both lithium and nickel, while using 60°C and no ultrasound with Li and 55°C and 40 KHz for Ni. For Co the best variables discovered were 1.5 molar concentration, 60°C and 40 KHz.

Assessment of Biofouling Using Leaching Rate of Antifouling Agents and Bioluminescent Assay

The authors investigated the leaching rate of antifouling agents from marine paint using an instrument that allows direct measurement from the flat bottom of ship hulls shortly after dry dock. A similar procedure was also used for painted flat panels that were immersed in the ocean. The relationship between leaching rate and fouling condition was considered by quantifying the amount of ATP （adenosine triphosphate） on the surface of immersed flat panel using fluorescence spectroscopy. The leaching rate results from ship hulls showed good agreement with the value by reporting of leaching rate of antifouling agents. The fluorescence spectroscopy results showed that the amount of ATP on the surface of the panel increased over time as the leaching rate fell, which implies an inverse relationship between leaching rate and fouling index. Fluorescence spectroscopy was also seen to be a simple method for evaluating the relationship between biofouling indexes and leaching rate.

Leaching Phenomena of Antifouling Agents from Ships＇ Hull Paints

The effects ofpH, dissolved ion content and relative water velocity on the release rate of an antifouling agent, cuprous oxide, from ships＇ hull paint have been investigated by rotating cylinder tests. Additionally, test paint panels were attached to a vessel and recovered after a certain period of voyage for the validation of the laboratory tests. In the initial period, the release rates are influenced by pH, dissolved ion content and water velocity, but once after a certain period of test, those effects become less significant. These phenomena can be explained when the paint film is fresh, the rate is controlled by chemical reaction, the surface and/or diffusion layer in the water phase governs the rate. After the antifouling substance in the paint film leached out from the near-surface region, a diffused layer （leached layer）, that has little antifouling agent remained, is formed at the surface of the coating, and the diffusion in that layer can be a rate-determining process. The development of the leached layer is affected by a balance between the leaching rate of the antifouling ingredient and paint resin determined by the chemical properties and speed of the water. Thus, the leaching rates of antifouling agents are affected by the history of the paint in the water.

Leaching characteristics of ion-adsorption type rare earths ore with magnesium sulfate

Magnesium sulfate was proposed to be leaching agent to deal with the ion-adsorption type rare earths ore to reduce or even eliminate ammonia?nitrogen emissions. The effects of temperature, particle size and stirring speed on rare earth leaching process and the leaching behaviors of the single rare earth element were investigated in order to reveal the rare earth leaching characteristics. Besides, the comparison of leaching effects between magnesium sulfate and ammonium sulfate was also studied. The results showed that the rare earth leaching process could be well described with inner diffusion control model and the apparent activation energy was 9.48 kJ/mol. The leaching behaviors of the single rare earth element were brought into correspondence with rare earths. Moreover, when the concentration of leaching agent was 0.20 mol/L, the rare earth leaching efficiency could all reach above 95% and the leaching efficiency of aluminum impurities could be restrained by 10% using magnesium sulfate compared with ammonium sulfate.

基于自适应数据融合的LEACH路由协议

如何有效地使用传感器节点的能量以延长WSN的生存时间,一直是WSN路由协议研究的重点。基于LEACH,提出了一种新的路由协议AF-LEACH,AF-LEACH根据数据融合的能量开销和所带来的节能增益,对传感器节点采集的数据进行自适应的数据融合。仿真实验表明,与LEACH协议以及在各节点都进行数据融合的MA-LEACH[1]协议相比,AF-LEACH在降低节点能耗,延长网络寿命等方面上有了显著提高。

Solidification Efficiency and Mechanism of Conventional Curing Agents for Sewage Sludge Stabilization and Dewatering

One of the challenges faced by sewage sludge treatment and disposal is its higher water content,and how to efficient dewater those hazardous materials properly is welcome in practice. This study stabilized the sewage sludge via the using of conventional curing agents and calcined aluminum salts,and the corresponding dewatering mechanisms and structural changes of the stabilized sludge were further comparable analyzed.Experimental results showed that wollastonite and kaolin exhibit a relative higher dewatering efficiency as compared to other conventional curing agents; however the releasing rate of heavy metals of Cu,Cr,Ni for kaolin solidification and Zn,Pb for wollastonite solidification is higher than the sludge samples solidified by other curing agents. For comparison,the sludge samples solidified by calcined aluminum salts (AS),calcium ash,Mg-based curing agent,tricalcium aluminate( C_3A) show a lower heavy metals leaching potential and unconfined compressive strength. In addition,the economic characteristics and local availability of AS,calcium ash,C_3A and CaO makes it have a broad prospect in extension and application. These findings are of great significance for stabilization and dewatering of sewage sludge.

Microstructure Formation and Degradation Mechanism of Cementitious Plugging Agent Slurries

The hydration products and microstructure of class G oil well cement and a newly developed plugging agent （YLD） slurries cured in the simulated temperature and pressure environment, which was of similar temperature and pressure with those at the bottom of oil well in a normal depth, were investigated using XRD, TG and SEM. Severe leakage is confirmed at the interface between hardened slurries and steel tube during the dynamically curing process, which induces the quick loss of cementing property of slurries. This should be the dominating cause of degradation of class G oil well cement slurry. A secondary hydration process can take place at the eroded interface of hardened YLD plugging agent slurry. Newly formed C-S-H gel has a self-healing effect to repair the damaged interface, which unceasingly maintains the cementing property of the YLD plugging agent slurry. Therefore, the effective using period of YLD plugging agent can be prolonged.

某低品位黏土型锂矿石的焙烧——无酸浸出试验研究

云南某低品位黏土型锂矿石含锂0.147%,为探究低能耗、环保的开发利用工艺,采用新型焙烧助剂ASH开展了低温焙烧—无酸浸出的提锂工艺研究,并结合XRD、SEM-EDS等分析手段阐述了反应机理。试验结果表明,在试样与ASH质量比为1∶0.3、焙烧温度为400℃、焙烧时间为1.0 h,去离子水浸出时间为2 h、浸出温度为70℃、液固比为5 m L/g条件下,锂浸出率为83.81%。机理分析显示,焙烧—浸出前后,样品中主要矿物相未发生变化,但衍射峰强度降低;经焙烧—浸出后,浸渣表面均匀分布着裂纹和空隙,Al、Si、Fe、Ti含量均有所降低。说明ASH与矿物发生反应,破坏了矿物的表面结构,生成了可溶性盐Li-ASH。与传统焙烧—浸出工艺相比,本研究所采用的提锂工艺焙烧温度低、浸出时无酸,降低了生产能耗、简化了工艺流程,对同类型低品位黏土型锂矿的绿色高效开发利用具有重要借鉴意义。

某高硫含砷难处理金矿选冶试验研究

针对某金矿中硫、砷含量过高且易泥化导致金回收率低的问题,采用阶段磨矿阶段浮选—浮选尾矿非氰浸出工艺流程开展试验研究。研究结果表明:在一段磨矿细度-0.074 mm占75.6%、二段磨矿细度-0.043 mm占78.1%,酸化水玻璃用量为1 650 g/t,硫酸铜用量为350 g/t,丁基黄药+丁铵黑药用量为(240+96) g/t,松醇油用量为160 g/t的条件下进行浮选试验,浮选尾矿采用非氰浸出剂进行非氰浸出,最终获得了浮选金精矿金回收率84.40%,浮选尾矿金浸出率10.52%,总金回收率94.92%的回收指标。研究结果对开发该类金矿资源具有重要指导意义。

不同螯合剂对褐煤中金属离子浸出效果的实验研究

螯合剂种类的不同,其对金属离子浸出效果也存在差异,为分析螯合剂对贵州地区褐煤中金属离子的浸出效果,选取ASDA,DTPA,IDS和GLDA等共4种螯合剂,开展了浸出效果对比实验,利用电感耦合等离子体质谱仪(ICP)和扫描电子显微镜(SEM)对实验结果进行了表征。结果表明:螯合剂能够将煤体中矿物质解络为游离态,煤体表面孔隙呈现从微孔、小孔向大孔变化的趋势,煤体表面矿物质呈现颗粒数量减少、颗粒体积变小、颗粒形态圆润的特点;ASDA对该煤样中Mg,Al,Fe,Ca,Cu离子具有最佳浸出效果,DTPA对K,Pb离子具有最佳浸出效果。

离子型稀土矿浸取剂阴离子对稀土和杂质铝浸出行为的影响

离子型稀土矿浸出过程常伴随杂质铝的浸出,这会增加后续除杂工序和成本,并造成稀土损失。为了保障稀土高效浸出的同时减少杂质铝离子的浸出,同时为离子型稀土矿绿色高效浸取剂的遴选提供方案,以不同阴离子体系(SO_(4)^(2−)、Cl^(−)、NO_(3)^(-)−和CH_(3)COO^(−))的铵盐和镁盐为浸取剂,考察了单一浸取剂浓度、液固比和流速及组合药剂对稀土和杂质铝浸出行为的影响。结果表明:随着浸取剂浓度、液固比的增加以及浸取剂流速的降低,稀土浸取率逐渐增大,不同阴离子对稀土浸出的促进效果为SO_(4)^(2−)>Cl^(−)>NO_(3)^(-)−>CH_(3)COO^(−),且镁盐的稀土浸取率高于铵盐。浸取剂中存在的乙酸根阴离子可以显著降低浸出液中的杂质铝浓度,在硫酸镁与乙酸镁组合药剂分步加药的最佳条件下,可获得稀土浸取率为97.36%、稀土离子质量浓度为706.34 mg/L、铝离子质量浓度为17.8 mg/L的浸出母液。

氧化剂对氰化体系下黄铁矿溶解行为的影响及机理

本文针对氰化过程金精矿中黄铁矿与氰化物作用特性,对比研究次氯酸钠、过氧化氢和过硫酸钠对黄铁矿的预氧化处理效果,并对黄铁矿溶解特性、氰化物消耗、硫氰酸根离子浓度及氧化渣表面物质组成变化进行了分析。结果表明:3种氧化剂均能抑制黄铁矿的氰化溶解,当以过硫酸钠为氧化剂时,氰化物的消耗量减少51.72%,硫氰酸根离子的生成量减少75.97%,同时氰化体系中的氧环境得到改善。但以次氯酸钠为氧化剂时,氯化物的释放导致氰化物的消耗量增加10.34%。SEM-EDS及XPS分析结果表明,氧化剂的使用导致黄铁矿表面形成了不与氰化物作用的FeO、FeSO_(4)和Fe_(2)(SO_(4))_(3),从而抑制了黄铁矿氰化溶解,优化了氰化提金系统的浸出环境。

硫酸镁和硫酸铵浸矿对离子吸附型稀土与重金属的释放与影响机理

传统的硫酸铵与新型的硫酸镁是目前离子吸附型稀土矿原位浸矿主要的浸矿剂,除了关注稀土的浸取效率,稀土浸取过程中是否会引起伴生重金属的释出而对地下水环境造成影响是值得关注的问题。为此,以江西龙南稀土矿为研究对象,对比研究硫酸镁和硫酸铵浸矿剂条件下,pH、固液比及浸矿剂浓度对稀土及Pb、Mn、Cd等金属离子释放与变化的影响。结果表明:稀土浸出率和重金属受pH影响较大,其次是固液比和浸矿剂浓度。pH对浸出液中金属释放影响程度从大到小为:Pb>Mn>Cd。根据微观表征,浸出前后稀土矿中的主要矿物相组成未发生明显变化,高岭石、钾长石等矿相表面的Mn、Fe等重金属通过离子交换作用进入浸出液。整体上,硫酸铵较硫酸镁对RE 3+的释放迁移影响更显著,可能加剧重金属离子的释放,造成地下水中重金属的超标。

塔吉克斯坦某含砷金精矿两段焙烧—浸出试验研究

塔吉克斯坦某含砷金精矿金品位73.27 g/t、砷品位6.61%、硫品位16.78%,是典型的难处理金精矿,采用直接氰化炭浆工艺处理时,金浸出率仅为88.02%。为提高金浸出率,进行含砷金精矿两段焙烧—浸出试验研究,制得的焙砂使用环保型浸出剂浸出。最终得到浸渣金品位4.32 g/t,金浸出率95.43%的良好指标,金浸出率提高7.41百分点,对处理同类型金矿资源起到指导作用。

低品位氧化铜原矿槽浸提铜工艺试验研究

试验采用原矿二级破碎-浓酸熟化-槽浸的流程,原矿破碎至粒径为5~10 mm后进行浓硫酸熟化,将熟化矿样直接用于浸出试验,在初始H_(2)SO_(4)浓度为100 g/L,液固比为1.5∶1,常温的条件下浸出24 h,Cu浸出率达到90%,浸出渣经水洗后洗液返回槽浸工序循环使用,Cu浸出率达到93%以上。槽浸浸出液即为CuSO_(4)溶液,可通过常规萃取-电解工艺得到最终产品阴极铜。试验结果表明:采用此工艺流程处理低品位氧化铜矿,Cu回收率达到93%以上。

老挝某含砷金矿非氰浸出试验研究

对老挝某含砷含碳金矿进行了非氰浸出试验研究,考察了磨矿细度、矿浆pH值、矿浆浓度(质量分数)、金蝉环保型黄金选矿剂用量对金浸出效果的影响。结果表明:采用过氧化氢预处理可以提升金浸出率;在磨矿细度-0.074 mm粒级占95%、搅拌速度2000 r/min条件下,采用过氧化氢500 g/t对矿浆预氧化处理3 h,然后再添加石灰3000 g/t、金蝉环保型黄金选矿剂5000 g/t,搅拌浸出30 h,尾渣金品位0.25 g/t,金浸出率92.27%,过氧化氢预氧化能使金浸出率提高1.96个百分点。

氰渣中硫氰酸盐测定方法研究

研究建立了氰渣中硫氰酸盐的测定方法,通过条件实验确定采用0.8%氢氧化钠为浸提剂,浸提方式为超声提取5 min,电热板180℃加热1 h,采用铁盐比色法测定硫氰酸盐。该方法测定结果的相对标准偏差为0.12%~0.93%,加标回收率为95.46%~100.50%,已在黄金行业氰渣中硫氰酸盐的测定得到广泛应用。

金浸出尾渣微波氯化焙烧试验研究

金浸出尾渣因含有多种有价元素如金、铜等,其处理工作一直面临着挑战。传统氯化焙烧可有效提取金浸出尾渣中有价元素,但该过程需高温且消耗煤炭、天然气,释放大量二氧化碳和烟气。为此,提出采用微波氯化焙烧的新方法,该方法具有低温、清洁的优势。研究了微波氯化焙烧对Au挥发率和Cl脱除率等指标的影响,探讨了微波功率、氯化剂种类、焙烧温度和CaCl_(2)用量等因素的作用。试验结果不仅阐明了微波氯化焙烧的工作原理,还评估了焙烧渣的毒性。与传统方法相比,微波氯化焙烧显著降低了有毒元素含量。

钢厂酸性废水循环浸出软锰矿工艺条件研究

以钢厂酸性废水为还原剂,研究了钢厂酸性废水还原浸出软锰矿工艺,以达到综合利用软锰矿和钢厂酸性废水的目的。结果表明,在FeCl2与MnO_(2)物质的量比2.2、浸出温度90℃、浸出时间3 h、液固比11∶1、初始酸性废水浓度2.5 mol/L条件下,软锰矿中Mn、Fe、Al的浸出率分别达到97.14%、95.37%和41.33%。采用废铁屑还原浸出液中Fe^(3+),在反应温度80℃、反应时间50 min、废铁屑加入量为理论量的1.1倍时,Fe^(3+)还原率达到99.85%。Fe^(3+)还原为Fe^(2+)后,含Fe^(2+)还原液返回浸出,浸出结果稳定,其中,软锰矿中Mn、Fe、Al平均浸出率分别达到96.75%、95.31%、41.18%。