Segregation behavior of magnetic ions in continuous flowing solution under gradient magnetic field

The research of magnetic separation starts from magnetic solid particles to nanoparticles, and in the research progress,particles become smaller gradually with the development of application of magnetic separation technology. Nevertheless,little experimental study of magnetic separation of molecules and ions under continuous flowing conditions has been reported. In this work, we designed a magnetic device and a ＂layered＂ flow channel to study the magnetic separation at the ionic level in continuous flowing solution. A segregation model was built to discuss the segregation behavior as well as the factors that may affect the separation. The magnetic force was proved to be the driving force which plays an indispensable role leading to the segregation and separation. The flow velocity has an effect on the segregation behavior of magnetic ions,which determines the separation result. On the other hand, the optimum flow velocity which makes maximum separation is related to the initial concentration of solution.

Pretreatment study on chloridizing segregation and magnetic separation of low-grade nickel laterites

The chloridizing segregation and magnetic separation of low-grade nickel laterites from Yunnan province of China was investigated.The nickel laterites were characterized by microscopic investigations,using X-ray diffractometry(XRD)and energy dispersive spectrometry(EDS)techniques.The pellets,which were prepared with magnesium chloride and coke as chloride agent and reductant respectively,were heated to a high temperature,and the pellets after cooling were crushed for magnetic separation.A series of experiments were conducted to examine the effect of chlorinating agent dosage,reductant dosage,chloridizing temperature and chloridizing time on enrichment grade of Ni and Co.The results indicate that the four factors have significant effects on the extractions of Ni and Co.The optimum conditions are as follows:the amounts of magnesium chloride and coke are 6%and 2%,respectively,chloridizing temperature is 1 253 K,and chloridizing time is 90 min.Under the conditions,extractions of Ni and Co reach 91.5%and 82.3%,respectively.

Mechanically activated starch magnetic microspheres for Cd(Ⅱ)adsorption from aqueous solution

Magnetic starch microspheres(AAM-MSM)were synthesized via an inverse emulsion graft copolymerization by using mechanically activated cassava starch(MS)as a crude material,acrylic acid(AA)and acrylamide(AM)as graft copolymer monomers,and methyl methacrylate(MMA)as the dispersing agent and used as an adsorbent for the removal of Cd(Ⅱ)ions from aqueous solution.Fourier-transform infrared spectroscopy(FT-IR),X-ray photoelectron spectroscopy(XPS),scanning electron microscopy(SEM),and vibrating sample magnetometry(VSM)were used to characterize the AAM-MSM adsorbent.The results indicated that AA,AM,and MMA were grafted to the MS,and the Fe_(3)O_(4) nanoparticles were encapsulated in the AAM-MSM adsorbent microspheres.The adsorbent exhibited a smooth surface,uniform size,and good sphericity because of the addition of the MMA and provided more adsorption sites for the Cd(Ⅱ)ions.The maximum adsorption capacity of Cd(Ⅱ)on the AAM-MSM was 39.98 mg·g^(-1).The adsorbents were superparamagnetic,and the saturation magnetization was 16.7 A·m^(2)·kg^(-1).Additionally,the adsorption isotherms and kinetics of the adsorption process were further investigated.The process of Cd(Ⅱ)ions adsorbed onto the AAM-MSM could be described more favorably by the pseudo-second-order kinetic and Langmuir isothermal adsorption models,which suggested that the chemical reaction process dominated the adsorption process for the Cd(Ⅱ)and chemisorption was the rate-controlling step during the Cd(Ⅱ)removal process.

噬菌体Pu29特性分析及其在沙门氏菌磁分离富集中的应用

以1株鸡白痢沙门氏菌噬菌体Pu29为研究对象,全面分析其生物学及基因组特性,将其作为识别元件,建立基于噬菌体Pu29的沙门氏菌磁分离富集技术。该噬菌体属于轮状病毒属(Roufvirus),具有二十面体的头部和不可收缩的长尾部。Pu29具有较宽的宿主谱,15min时对宿主细胞的吸附率为88.67%,潜伏期为30min,裂解期为180 min,裂解量为115.74 PFU/cell。同时Pu29具有较好的耐热性(30~60℃)和pH值耐受性(pH 4~11)。Pu29基因组由45715bp(GC含量46.08%)和81个开放阅读框组成,包括18个具有已知功能的阅读框,不携带编码毒性或抗性因子的基因。通过酰胺反应将噬菌体Pu29与羧基化的纳米磁珠偶联制备探针PhagePu29-MBs。使用25μg探针与沙门氏菌在37℃孵育20min时,对沙门氏菌的捕获效率最高可达到83.93%,最低捕获细菌浓度为45CFU/mL。采用透射电镜观察到PhagePu29-MBs能够特异性地捕获沙门氏菌。在加标样品中,PhagePu29-MBs分离富集沙门氏菌的捕获效率最高能达到92.92%。该方法分离富集沙门氏菌的时间大约为30min。因此,本研究基于噬菌体Pu29建立了一种快速、特异性强的沙门氏菌磁分离方法,可为基于噬菌体快速分离富集食源性病原菌奠定研究基础。

某风化低品位石煤钒矿超导磁选预富集试验研究

针对某风化低品位石煤钒矿品位低、直接提钒工艺复杂且成本高的难题,开展选矿预富集试验研究。工艺矿物学研究结果表明,该石煤中钒主要赋存在含钒褐铁矿和含钒云母中,以上2种矿物均具有微弱磁性,可采用超导磁选-沉降工艺预富集钒。在磁场强度4 T、矿浆流速8.0 L/min条件下,获得了V_(2)O_(5)品位1.44%、回收率55.08%的超导磁选预富集精矿,超导磁选尾矿可通过沉降分级进一步回收钒,最终可获得V_(2)O_(5)品位1.03%、回收率79.48%、抛尾率高达59.02%的综合精矿,实现对该石煤中钒的高效富集,满足了后续冶金法提钒的要求。

黄沙坪多金属矿强磁选抛废-强化锡石富集试验研究

为了实现黄沙坪多金属矿中低品位伴生锡石的资源化利用,开展了高梯度磁选抛废试验和浮选试验,开发了高梯度强磁选抛废-强化钨锡浮选富集的选矿新工艺。通过高梯度磁选预先抛废,钼、钨、萤石抛废损失率均低于10%,锡石显著富集于强磁选粗精矿中;使用Pb-BHA-SPA多配体金属基捕收剂对强磁选粗精矿进行再磨后精选,可得到WO_(3)和SnO_(2)品位分别为0.627%和0.78%、对应回收率分别为26.56%和18.03%的钨锡混合精矿。该工艺为低品位伴生锡石的强化富集和高效利用提供了新思路和新方法。

司家营综合尾矿预富集—悬浮磁化焙烧试验研究

尾矿持续堆存导致了一系列的安全和生态环境问题,提高尾矿综合利用率,实现尾矿规模化消纳成为矿山企业绿色发展的必然要求。司家营铁矿综合尾矿的铁品位为9.84%,铁主要以赤褐铁矿和磁铁矿的形式存在。针对尾矿铁品位低的问题,提出了预富集—悬浮磁化焙烧—弱磁选的工艺流程。结果表明:原矿经过弱磁选—强磁选—磨矿(-0.038 mm占95%)—弱磁选—强磁选工艺,获得了铁品位20.94%、回收率64.08%的预富集精矿。预富集精矿在焙烧温度540℃、CO浓度20%、还原时间15 min、总气量350 mL/min的条件下焙烧,焙烧产品磨细至-0.025 mm占70%经弱磁选分离可得到铁品位65.61%、回收率53.68%的磁选精矿。

废旧锂离子电池涡流分选模型与影响因素

废旧锂离子电池的涡流分选工艺由于影响参数过多,分选效果并不理想。为探明各参数对分选效果的影响,提高涡流分选法的分离效率,开展废旧磷酸铁锂锂离子电池破碎产物的涡流分选研究。利用COMSOL仿真软件模拟磁辊交变磁场分布,建立产物在交变磁场的受力模型与运动模型,研究磁辊长度、磁极对数、磁辊半径、进料速度、磁辊转速、颗粒尺寸和颗粒形状等因素对分选效果的影响,提出将传送带摩擦因数纳入影响参数之中进行模拟,以指导涡流分选模型的建立。上述因素均会影响颗粒的运动轨迹,减小摩擦因数有利于提高分选效率,颗粒尺寸和形状是主要的影响因素。

某锂云母粗精矿磁选再富集试验研究

江西某锂云母经浮选后粗精矿锂品位2.60%左右,产品竞争力较弱。为提高该锂云母精矿的市场竞争力,达到锂品位3.0%以上的要求,进行锂云母粗精矿磁选再富集试验。研究结果表明:在磨矿细度-0.074 mm65%、给矿浓度25%、磁介质棒直径3 mm、强磁粗选1背景磁感应强度1.3T、强磁粗选2背景磁感应强度1.5 T的条件下,采用2次强磁粗选工艺流程,可获得锂品位3.03%、锂回收率82.03%的锂云母强磁选精矿;试验达到了对现场浮选精矿再富集的效果,可作为现场工艺改造的依据。

磁性材料在固相萃取汞中的研究进展

汞在自然界中分布广泛,随着水体、土壤、大气和生物圈迁移和转化并在生物体内富集,人体由于直接或间接地接触汞污染的水源、土壤、食物等引发各种疾病,汞被认为是对人类和环境最具危害性的重金属元素之一。相较于其他有机化合物的污染,某些有机化合物可以经由自然界物理、化学或是生物过程得到净化以减轻其有害性,但重金属(尤其是汞)则难以在环境中降解消除。但是一般样品中汞的含量是在痕量或者超痕量的水平,很难准确检测出汞的形态以及含量,所以目前都是在检测前对样品进行前处理-对汞进行分离富集。本文简单综述了在汞分离富集领域-固相萃取中磁性材料的研究进展。

Iron recovery and rare earths enrichment from Bayan Obo tailings using Coal-Ca(OH)2-NaOH roasting followed by magnetic separation

The recovery of iron and enrichment of rare earths from Bayan Obo railings were investigated using Coal Ca（OH） 2 NaOH roasting followed by magnetic separation. The influences of roasting temperature, roasting time, coal content, milling time, Ca（OH）2 dosage and NaOH dosage on the iron and rare earths recovery were explored. The results showed that the magnetic concentrate containing 70.01 wt. % Fe with the iron recovery of 94.34G and the tailings of magnetic separation containing 11.46 wt. % rare earth oxides （REO） with the REO recovery of 98. 19% were obtained under the optimum conditions （i. e. , roasting temperature of 650℃, roasting time of 60 min, coal content of 2.0%, milling time of 5 min, and NaOH dosage of 2.0%）. The Ca（OH）2 dosage had no effect on the separation of iron and rare earths. According to the mineralogical and morphologic analysis, the iron and rare earths of Bayan Obo tailings could be utilized in subsequent ironmaking process and hydrometallurgy process.

A Novel Magnetic Separation Oxygen-enriched Method and the Influence of Temperature and Magnetic Field on Enrichment

A novel oxygen-enriched method is presented. Using two opposite magnetic poles of two magnets with certain distance forms a magnetic space having a field intensity gradient near its borders. When air injected into the magnetic space outflows from the magnetic space via its borders, oxygen molecules in air will experience the interception effect of the gradient magnetic field, but nitrogen molecules will outflow without hindrance. Thereby the continuous oxygen enrichment is realized. The results show that the maximum increment of oxygen concentration reaches 0.49% at 298 K when the maximum product of magnetic flux density and field intensity gradient is 563T^2/m. The enrichment level is significantly influenced by the gas temperature and the magnetic field. The maximum increment of oxygen concentration drops to 0.16% when the gas temperature rises to 343 K, and drops to 0.09% when the maximum product of magnetic flux density and gradient is reduced to 101 T^2/m from 563 T^2/m.

Application of magnetic solid phase extraction in separation and enrichment of glycoproteins and glycopeptides

The analysis of endogenous glycoproteins and glycopeptides in human body fluids is of great importance for screening and discovering disease biomarkers with clinical significance.However,the presence of interfering substances makes the direct quantitative detection of low-abundance glycoproteins and glycopeptides in human body fluids one of the great challenges in analytical chemistry.Magnetic solid phase extraction(MSPE)has the advantages of easy preparation,low cost and good magnetic responsiveness.Magnetic adsorbents are the core of MSPE technology,and magnetic adsorbents based on different functional materials are widely used in the quantitative analysis of glycoproteins and glycopeptides in human body fluids,making it possible to analyze glycoproteins and glycopeptides with low abundance as well as multiple types,which provides a technical platform for screening and evaluating glycoproteins and glycopeptides in body fluids as disease biomarkers.In this paper,we focus on the recent advances in the application of MSPE technology and magnetic adsorbents for the separation and enrichment of glycoproteins and glycopeptides in human body fluids,and the future trends and application prospects in this field are also presented.

Localization of rare earth ions in an inhomogeneous magnetic field toward their magnetic separation

Efficient extraction and recycling methods are an important issue for rare earth elements(REE). The significant differences in their magnetic moments make magnetic separation a promising step. Although the magnetic field gradient manipulation of ions seemed to be impossible, the robust enrichment of some paramagnetic RE ions was found in the vicinity of the magnet. The studies in recent years resolved the physical paradox of why, despite the Brownian motion of the ions, there is a reproducible enrichment of RE ions in magnetic field gradients. The existence of trigger process and energy barrier was proved.However, these studies usually used only high paramagnetic ions, e.g., Dy(Ⅲ) or Ho(Ⅲ). This work verifies the theory of the possible magnetic separation for 8 different rare earth ions, respectively. For this purpose, concentration distribution in rare earth chloride solutions were measured using a MachZehnder interferometer. The magnetic field was assured by a Halbach configuration to enhance the effect. The results show the classification of RE solutions into 2 classes: Class I contains the REs with low magnetic moment, whereas Class II includes the REs of high magnetic moment. Only the latter group shows the enrichment of ions in the vicinity of the magnet which encourages the implementation of magnetic separation into existing hydrometallurgical technology to enhance the selectivity of REE.

Highly efficient enrichment and adsorption of rare earth ions(yttrium(Ⅲ))by recyclable magnetic nitrogen functionalized mesoporous expanded perlite

A magnetic mesoporous expanded perlite-based(EPd-APTES@Fe3 O_(4))composite was designed and synthesized as a novel adsorbent for enrichment of rare earth ions in aqueous solution.Effect of various factors including the pH of solution,contact time and adsorbent dosage on the adsorption behaviors of yttrium(Ⅲ)by the EPd-APTES@Fe3 O_(4) nano-material composites from aqueous solution was investigated.The maximum adsorption capacity of the as-prepared materials for yttrium(Ⅲ)ions was 383.2 mg/g.Among the various isotherm models,the Freundlich isotherm model could well described for the adsorption of the rare ea rth ions at pH 5.5 and 298.15 K.The kinetic analysis indicated that the adsorption process followed the pseudo-second order kinetics model,and the rate-determining step might be chemical adsorption.Thermodynamic parameters declared that the adsorption process was endothermic.In addition,Fourier transform infrared spectroscopy(FTIR),X-ray photoelectron spectroscopy(XPS)and the quantum chemical calculation indicated that the yttrium(Ⅲ)ions were captured on the EPd-APTES@Fe3 O_(4) surface mainly by coordination with functional group of-NH2.More importantly,the adsorption-desorption studies indicated that the EPd-APTES@Fe3 O_(4) nano-material composites had a high stability and good recyclability.

水源性致病微生物检测中水样前处理方法研究进展

水中的微生物水平(细菌、病毒、原虫等)是衡量水质安全的重要指标,水源性致病微生物通过饮水和直接接触等途径感染人体,存在传播各类疾病的风险,关乎人群生命健康。由于致病微生物在环境水体中通常以较低浓度存在,在检测过程中均需先对水样进行前处理将其浓缩成较小的体积。文中介绍了可用于水体中致病微生物富集浓缩的富集培养、离心、过滤和磁性分离等前处理方法的研究进展,讨论了不同前处理方法的优缺点和适用范围,以实现水体中致病微生物的准确检测,真实反映致病微生物在水体中的赋存状况,为水体中致病微生物分析检测和风险控制提供技术支撑。如离心和过滤适用范围广泛,适用于水源性致病微生物的非特异性富集,富集培养和磁性分离特异性较强,更适用于水源性致病微生物的特异性富集。

磁—浮联合工艺回收矽卡岩型钨尾矿中萤石试验研究

为有效利用江西某钨尾矿中的萤石,基于尾矿性质,确定采用强磁选抛尾预富集萤石—浮选高效富集的选矿工艺流程开展综合回收试验。尾矿样经“1粗1精”高梯度强磁选预富集处理后,萤石与方解石富集至非磁产品和强磁中矿,CaF_(2)、CaCO_(3)的累计回收率分别达94.82%、94.77%,而强磁产品的CaF_(2)、CaCO_(3)品位分别降至3.29%、2.96%。将非磁产品和强磁中矿合并为浮选给矿开展药剂制度研究,条件试验确定采用GYSH作为硅矿物抑制剂,适宜用量为3000g/t;GY51作为碳酸盐矿物抑制剂,适宜用量为150g/t;GYOZ作为萤石捕收剂,适宜用量为150g/t。在适宜的药剂制度条件下,全流程闭路试验可获得CaF_(2)品位96.37%、CaF_(2)回收率84.58%、CaCO_(3)含量1.57%的萤石精矿。研究开发的工艺流程及药剂制度大幅减少萤石浮选处理量,实现了萤石的高效回收,为同类型钨尾矿的资源化利用提供了技术依据。

Magnetically separated and N, S co-doped mesoporous carbon microspheres for the removal of mercury ions

Magnetically separated and N, S co-doped mesoporous carbon microspheres （NIS-MCMs/Fe304） are fabricated by encapsulating Si02 nanoparticles within N, S-containing polymer microspheres which were prepared using resorcinol/formaldehyde as the carbon source and cysteine as the nitrogen and sulfur co-precursors, followed by the carbonization process, silica template removal, and the introduction of Fe3O4 into the carbon mesopores. N/S-MCMs/Fe3O4 exhibits an enhanced Hg2＋ adsorption capacity of 74.5 rag/g, and the adsorbent can be conveniently and rapidly separated from wastewater using an external magnetic field. This study opens up new opportunities to synthesize well- developed, carbon-based materials as an adsorbent for potential applications in the removal of mercury ions from wastewater.

某采场剥离废石中铜的预富集-浮选试验研究

针对国内某矿山采场剥离废石中有色金属的回收进行了高效预富集技术研究。工艺矿物学研究表明,剥离废石中不同目的矿物的共生关系整体较为简单。试验结果表明,将含铜0.25%左右的剥离废石分成多个粒级,通过磁选、光电选设备与不同工艺流程相结合,探究剥离废石中有色金属的富集情况。

两亲性雪人状Janus颗粒用于油水分离

通过种子溶胀乳液聚合诱导相分离法合成具有严格分区的雪人状Janus颗粒,分别对两侧分区结构连续改性,制备得到具有磁响应性的两亲雪人状Janus颗粒.该颗粒一侧带有亲水性咪唑基团(—Im),另一侧带有疏水性烷基长链(—C18),对油相具有强的负载能力;同时该颗粒具有顺磁响应性,其可以稳定在油水界面上,并在磁场作用下驱使乳液液滴进行运动,实现高效的油水分离应用,颗粒可回收循环利用,符合绿色化学要求.该功能性Janus颗粒的制备方法具有普适性,对颗粒两侧进行不同改性,可以获得一系列不同组成和功能的Janus颗粒,为制备先进功能高分子材料提供新的思路.