One-Step Synthesis of Magnetic Zeolite from Zinc Slag and Circulating Fluidized Bed Fly Ash for Degradation of Dye Wastewater

In this study,a magnetic P zeolite was directly synthesized by utilization of industrial solid wastes of zinc slag(ZS)and circulating fluidized bed fly ash(CFBFA)via one-step hydrothermal method.The effects of different CFBFA/ZS ratios and hydrothermal times on the as-synthesized zeolite were investigated.The X-ray diffraction(XRD)and vibrating sample magnetometer(VSM)results indicated that the magnetic P zeolite possessed well-defined crystals and superparamagnetism.The as-prepared zeolite was employed as a Fenton-like solid catalyst for degradation of direct green B dye wastewater.It was discovered that the magnetic P zeolite took the advantage of rapid separation and efficient recovery under the external magnets in a solid-liquid reaction.The effects of the solution pH,the catalyst dosage,and the H_(2)O_(2)concentration on the degradation rate of direct green B dye wastewater were studied systematically.The results showed that the highest degradation of 96.3%was obtained and the magnetic P zeolite showed excellent stability after four cycles.Therefore,the magnetic P zeolite derived from industrial solid wastes had a potential application in wastewater treatment.

Effect of Wood Waste on Acoustic and Magnetic Properties of Composite Bricks and Correlation between Sound Velocity and Magnetic Induction in These Bricks

In the present study, kambala (botanical name: Chlorophora excelsa and Chlorophora regia) wood wastes were incorporated into stabilized earth bricks in order to test their acoustic insulation capacity of the walls;leading to better waste management from the timber industry. Two methods have been applied to determine the influence of the wood waste content in the stabilized earth bricks, on the weakening of the level of noise reception coming from the environmental medium, in an apartment built with composite bricks (earth + wood chips + cement). This influence has also been analyzed on the magnetic field induced by these bricks. The results showed that the level of sound reception through these bricks decreases with increasing wood waste content regardless of the method used (from 110 dB to 68 dB, respectively for Φb = 0% and Φb = 8%). The kambala wood waste in cement-stabilized clay bricks induces a magnetic field that increases with the wood waste content;the high contents of the wood chips causing an increase in the magnetic permeability of the composite medium. The correlation between the noise level and the magnetic field of the bricks shows that the noise level declines with increasing magnetic induction of the bricks.

Experimental study on separation of valuable refractory aggregate from investment casting ceramic shell waste

In the present study, a processing technique for recycling investment casting ceramic shell waste was proposed to separate valuable refractory aggregate zircon sand. The microstructure and phase constituents of the shell waste and separation process were investigated. The results show that the characteristics of microstructure and phase constituents of the shell waste can meet the conditions for preferential y separating zircon sand, and zircon sand can be separated by gravity separation on a shaking table. The separated zircon sand has good shape and high purity, and can be used for the production of castings and other applications.

Recovery of iron from copper slag by deep reduction and magnetic beneficiation

Aiming at recovering iron from high-iron-content copper slag, this article introduced a combination technol- ogy of deep reduction and magnetic beneficiation, investigated the iron recovery efficiency and optimized the technical conditions. When coke powder with 86wt% fixed carbon was used as a reductant, iron was successfully extracted from the copper slag. Under the optimized condition of the coke powder content of 14wt%, the calcium-to-silicon mass ratio （Ca/Si） of 0.2, the roasting temperature of 1300℃, the roasting time of 3 h, the grinding time of 20 min, and the magnetic field intensity of 61 kA-m-1, the iron recovery rate of the copper slag can reach 91.82%, and the extracted iron powder has an iron grade of 96.21%. With the characteristics of high iron grade and low impurity content, the extracted iron powder can be used as high-quality raw materials of weathering steel.

Flow-mode synthesis of biodiesel under simultaneous microwave–magnetic irradiation

In this study,aiming at optimization of a novel continuous biodiesel production system was developed by combining technologies based on microwaves and magnetic fields.Factors affecting microwave-assisted biodiesel(alkyl esters)production reaction were analyzed in this investigation.Studied factors included magnetic field intensity(0,0.225 and 0.450 T),microwave power(400,821,and 1181 W),percentages of KOH and Na OH catalysts at constant concentrations of 1 wt%(0,50%and 100%),and percentages of ethanol and methanol at a constant molar ratio of 6:1(0,50%and 100%).Response Surface Methodology(RSM)was used to optimize the reaction conditions.RSM-based analysis indicated that,all independent parameters had significant effects on the reaction efficiency.Results of the investigations reveal that the largest effects on the conversion efficiency were due to type of alcohol and magnetic field intensity.The optimized conditions were found to be a magnetic field intensity of 0.331 T,a microwave power of 677.77 W,catalyst percentages of 30.35%and 69.65%for KOH and Na OH,respectively,and alcohol percentages of 80.47%and 19.53%for methanol and ethanol,respectively.Under the optimal conditions,yield of the reaction was 96.2%.

ARSENIC REMOVAL BY SULFIDATION SEDIMENTATION IN MAGNETIC FIELD

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磁性生物炭的制备及其在污染治理中的应用研究进展

磁性生物炭(MBC)能够解决吸附后的生物炭(BC)不易从环境中分离的问题。负载在BC上的磁性前驱体在污染物去除中表现出很好的还原和催化活性。本文根据负载在BC上的磁性材料对MBC进行分类,对MBC的制备方法、催化机理和研究进展进行综述,提出了目前MBC研究所面临的问题,为MBC在有机污染治理中的应用作参考。

磁性煤气化渣的制备及吸附特性研究

以固体废弃物煤气化渣为原料,采用酸浸与化学共沉淀法制备磁性煤气化渣(MCGS),并利用扫描电子显微镜(SEM)、傅立叶变换红外光谱仪(FTIR)、X射线衍射仪(XRD)对制备的MCGS进行了表征。研究结果表明:MCGS呈现出粗糙、多孔的结构,而且其表面与孔道中负载了分布较为均匀的、具有反尖晶石结构的Fe3O4粒子。进而以罗丹明B(RhB)为目标污染物,对其吸附性能进行了研究,当溶液pH为3.0,吸附时间为200 min, RhB初始质量浓度为200 mg/L,MCGS用量为2.0 g/L时,RhB的去除率为90.66%,吸附容量为90.66 mg/g。吸附等温线与吸附动力学研究结果表明:MCGS对RhB的吸附动力学与准二级动力学模型相吻合,吸附等温线与Langmuir相一致,说明该过程是一个单分子层吸附、以化学吸附为主的过程。该研究为煤气化渣的资源化利用提供了新的技术与方法。

某铁基合金废料工艺矿物学及磁选回收试验研究

国内某合金磨屑废料中富含金属铁和铁氧化物,为实现其资源化利用,采用化学多元素、铁物相、MLA和SEM-EDS等手段进行了工艺矿物学研究。结果表明:原料主要物质组成为金属铁,含量为77.52%;其次为铁氧化物和铝氧化物,含量分别为11.13%和8.97%;原料中主要物质的粒度较细,铁氧化物和金属铁-38μm粒级产率分别为72.53%和63.66%;原料中金属铁和铝氧化物的单体解离度较高,金属铁、铁氧化物以及铝氧化物之间的连生体可通过磨矿实现单体解离。原料磁选获得了铁品位84.92%、铁回收率92.37%的精矿产品,其脱铝效果良好,但无法实现硅的有效脱除。

Acceleration of floc-water separation and floc reduction with magnetic nanoparticles during demulsification of complex waste cutting emulsions

Waste cutting emulsions are difficult to treat efficiently owing to their complex composition and stable emulsified structure.As an important treatment method for emulsions,chemical demulsification is faced with challenges such as low flocs-water separation rates and high sludge production.Hence,in this study,Fe3O4 magnetic nanoparticles(MNPs)were used to enhance chemical demulsification performance for treating waste cutting emulsions under a magnetic field.The addition of MNPs significantly decreased the time required to attain sludge-water separation and sludge compression equilibrium,from 210 to 20 min.In addition,the volume percentage of sludge produced at the equilibrium state was reduced from 45% to 10%.This excellent flocculation-separation performance was stable over a pH range of 3-11.The magnetization of the flocculants and oil droplets to form a flocculant-MNP-oil droplet composite,and the magnetic transfer of the composite were two key processes that enhanced the separation of cutting emulsions.Specifically,the interactions among MNPs,flocculants,and oil droplets were important in the magnetization process,which was controlled by the structures and properties of the three components.Under the magnetic field,the magnetized flocculant-MNP-oil droplet composites were considerably accelerated and separated from water,and the sludge was simultaneously compressed.Thus,this study expands the applicability of magnetic separation techniques in the treatment of complex waste cutting emulsions.

Recycling of waste Nd-Fe-B sintered magnets by doping with dysprosium hydride nanoparticles

Recycling of waste sintered Nd-Fe-B permanent magnets by doping DyH3 nanoparticles was investigated. The effect of the DyH3 nanoparticles on the microstructure and magnetic properties of the recycled magnets was studied. As the DyH3 nanoparticles additive increased, the coercivity of recycled magnet increased gradually. The recycled magnets with DyH3 nanoparticle content between 0.0 wt.% and 1.0 wt.% maintained the remanence （Br）, but, with higher additions, the Br began to decrease rapidly. The best recycled magnet produced contained 1.0 wt.% of DyH3 nanoparticles when compared to the properties of the starting waste sintering magnet. The Hcj, Br and （BH）max values of 101.7%, 95.4%, and 88.58%, respectively, were recovered.

瑶岗仙黑钨矿采矿废石资源化利用研究

湖南瑶岗仙黑钨矿采选历史悠久,近百年的开采产生了大量的废石,不仅造成了资源浪费,还存在环境风险。本文针对瑶岗仙黑钨矿采矿废石资源综合利用开展了系统研究:采用两段一闭路制砂工艺可以得到–31.5 mm+20 mm、–20 mm+10 mm、–10 mm+5 mm三个粒级的粗骨料和–5 mm+1 mm粒级的细骨料,其物理化学性能均能满足国家标准中各类砂石骨料的技术要求;对制砂过程产的–1 mm次生细泥采用强磁粗选—摇床精选联合工艺,可以得到合计品位为55.75%、回收率为58.39%的钨精矿产品。该技术基本实现了黑钨废石的资源化利用和有价金属的综合回收。

硝酸钡预处理高放废液玻璃固化体结构和抗浸出性能研究

为提高硼硅酸盐玻璃对硫的包容能力,采用Ba(NO_(3))_(2)将模拟高硫高钠废液中的SO_(4)^(2-)转变为BaSO_(4),再利用熔融法制备硼硅酸盐玻璃固化体,研究了模拟高放废液掺量对玻璃固化体结构和抗浸出性能的影响。结果表明:采用Ba(NO_(3))_(2)对模拟高硫高钠废液进行预处理后,废物包容量达到23%(质量分数)仍未发生分相;掺入模拟高放废液的玻璃固化体中的Na、B、Si元素归一化质量损失比纯硼硅酸盐玻璃低一个数量级,随着模拟高放废液掺量增加玻璃固化体抗浸出性能无明显变化。^(11)B和^(29)Si核磁共振谱分析表明,模拟高放废液的掺入使部分BO_(3)结构转变为BO_(4)结构,玻璃网络结构有所增强。

磁性樟树叶生物炭对水体中亚甲基蓝的吸附研究

以园林植物樟树落叶为原料,制备磁性生物炭,并以此作为吸附剂,来去除水体中的亚甲基蓝。应用平衡吸附法,研究了吸附剂的投加量、溶液的初始浓度、吸附时间、pH、共存离子对吸附效果的影响。结果表明,随着炭投加量的增加,吸附量逐渐降低,去除率逐渐增加并趋于平衡,最大去除率为99.69%。磁性樟树叶生物炭对亚甲基蓝的吸附符合Langmuir吸附等温线和准二级动力学模型,吸附量随着pH的下降而降低,共存离子HPO_(4)^(2-)对吸附有一定抑制作用。磁性樟树叶生物炭可以作为一种新型高效、易回收的吸附剂用于印染废水处理,为园林废弃物资源化利用提供了一种可行的技术手段。

Coupling magnetic particles with flocculants to enhance demulsification and separation of waste cutting emulsion for engineering applications

Magnetic particles were coupled with a flocculant to enhance the demulsification and separation of waste cutting emulsions.The optimal magnetic particle size and critical magnetic field conditions were investigated to achieve large-scale engineering application of magnetic demulsification separation for waste cutting emulsion treatment.The micro-scale magnetic particles were found to show comparable effects to nano-scale magnetic particles on enhancing the demulsification and separation of cutting emulsions,which are beneficial for broadening the selectivity of low-cost magnetic particles.The critical magnetic separation region was determined to be an area 40 mm from the magnetic field source.Compared to the flocculant demulsification,the magnetic demulsification separation exhibited a significant advantage in accelerating flocs-water separation by decreasing the separation time of flocs from 180-240 min to less than 15 min,compressing the flocs by reducing the floc volume ratio from 60%-90%to lower than 20%,and showing excellent adaptability to the variable properties of waste cutting emulsions.Coupled with the design of the magnetic disk separator,continuous demulsification separation of the waste cutting emulsion was achieved at 1.0 t/hr for at least 10 hr to obtain clear effluent with 81%chemical oxygen demand removal and 89%turbidity reduction.This study demonstrates the feasibility of applying magnetic demulsification separation to large-scale continuous treatment of waste emulsion.Moreover,it addresses the flocs-water separation problems that occur in practical flocculant demulsification engineering applications.

黄芪废渣磁性碳化吸附剂制备及其对水中四环素的吸附动力学研究

以黄芪废渣和氯化铁混合物为原料,采用限氧热解法在700℃焙烧,制备黄芪废渣磁性碳化吸附剂(HC),研究其对四环素的吸附性能,考察的实验条件主要有四环素浓度、溶液pH、吸附剂用量、震荡时间。得出实验结论:在四环素溶液浓度140.0 mg/L、溶液pH5.6、黄芪废渣磁性碳化吸附剂的添加量2.5 g/L、震荡搅拌时间50 min时,吸附率最高可达94.1%,吸附量为52.696 mg/g。动力学分析实验结果表明黄芪废渣磁性碳化吸附剂(HC)对水中四环素的吸附过程与伪二级动力学模型更为一致。

Short-process recycling of Nd-Fe-B sintered magnet sludge wastes:Challenges and approaches

Nd-Fe-B sintered magnet sludge wastes are one kind of typical commodity of recyclable rare-earth permanent magnet resources,and recycling such kind of wastes with economical and environmentally friendly techniques is crucial to the sustainable rare-earth industry.However,the current multistage wet process recycling technique for the sludge wastes involves high fabrication cost,excessive energy consumption,and heavy environmental burden.Therefore,short-process recycling techniques for Nd-Fe-B sintered magnet wastes have drawn increasing attention in the past decades.In this paper,we review recent efforts into short-process recycling Nd-Fe-B sintered magnet sludge wastes with emphasis on in-situ recycling techniques.

赤泥/废菌渣磁性生物炭的制备及对水中诺氟沙星的吸附

以氧化铝行业废弃物赤泥和食用菌产业废弃物菌棒为原料,采用共热解法制备赤泥/废菌渣磁性生物炭(RMMBC),解析其形貌特征、孔隙结构及表面官能团变化等情况,探究其对水中诺氟沙星(NOR)的吸附效果,通过吸附动力学和等温吸附特性探究其吸附机制,并在实际废水进行试验。结果表明,最佳制备条件为原料比(赤泥、废菌渣、尿素)1∶2.5∶0.5、煅烧时间1 h、煅烧温度700℃。水中NOR浓度为10 mg/L,投加0.25 g RMMBC,其对NOR的最大去除率为96.3%。结果表明,RMMBC具有较大的比表面积(59.295 m^(2)/g)、孔体积(20.157 cm^(3)/g)和饱和磁化率(16.735 emu/g)。RMMBC准二级动力学和Freundlich等温模型能较准确地描述NOR在RMMBC上的吸附过程,表明化学吸附可能是NOR在RMMBC上吸附的主要机制,主要为π-π相互作用、表面络合、疏水作用、氢键和静电作用。利用赤泥和废菌渣制备磁性生物炭吸附效果显著,兼具便于从水体中分离的优势,避免对环境造成二次污染,不仅为低成本处理抗生素废水提供新思路,还有助于实现赤泥与废菌渣的稳定化、无害化、资源化利用,实现“以废治废”的环保目标。

纳米磁性材料CuFe_(2)O_(4)/rGO吸附废水中亚甲基蓝

以还原氧化石墨烯(rGO)和铁酸铜(CuFe_(2)O_(4))为原料,采用水热法制备了纳米磁性材料CuFe_(2)O_(4)/rGO,采用TEM、XRD、FTIR、XPS、TG等技术手段进行了表征,并考察了CuFe_(2)O_(4)/rGO对溶液中亚甲基蓝(MB)的吸附性能。表征结果显示:CuFe_(2)O_(4)纳米粒子呈方形或梭形,均匀分散在rGO片层上,平均粒径66 nm;CuFe_(2)O_(4)/rGO具有超顺磁性。在初始MB质量浓度20 mg/L、溶液pH 9.3、CuFe_(2)O_(4)/rGO加入量2.5 g/L、吸附时间100 min的条件下,CuFe_(2)O_(4)/rGO对MB的吸附量为33.20 mg/g,溶液中MB的去除率为83.0%。Langmuir等温吸附模型能够更好地描述CuFe_(2)O_(4)/rGO对MB的等温吸附过程,25℃时,CuFe_(2)O_(4)/rGO对MB的理论饱和吸附量为41.09 mg/g。CuFe_(2)O_(4)/rGO对溶液中MB的吸附动力学过程符合准二级动力学模型。

利用粉煤灰制备Ni负载的微波吸收材料

粉煤灰(CFA)的回收利用对缓解日益严重的环境污染具有重要意义。本文以CFA为原料,利用简单的“一锅法”设计合成负载Ni的复合微波吸收材料(Ni/CFA-x),以实现低成本吸收材料的制备和CFA资源回收利用。研究表明,随硝酸镍前驱体溶液浓度的增加,材料的吸波效果先增强后减弱。负载适量的金属Ni颗粒,使得材料介电和磁性组分之间的有效复合表现出显著增强的微波吸收性能。当硝酸镍前驱体溶液浓度为1.0 mol/L时,材料的吸波效果最佳,在2.0 mm涂层厚度下,材料最小反射损耗达到-47.9 dB,对应的有效吸收带宽达到4.2 GHz。材料优异的吸波性能主要源于金属Ni颗粒与一定石墨化程度碳引起的导电损耗及其与CFA基体各组元间的界面极化损耗。