Hydrometallurgical process and recovery of valuable elements for limonitic laterite:A review

Nickel is a strategic resource in social life and defense technology,playing an essential role in many fields,such as alloys and batteries.With the decrease in nickel sulfide,it is of great significance to extract nickel from laterite.The limonitic laterite is a kind of rich nickel-cobalt-scandium resource.At present,there are few reviews on the extraction of limonitic laterite.This study reviews the hydrometallurgical processes for limonitic laterite ores and the methods of recovering valuable elements.The mineralogical characteristics are analyzed,and the typical mineral compositions are summarized.The main hydrometallurgical processes are compared and discussed,including reduction roasting-ammonia leaching,sulfuric acid pressure leaching,nitric acid pressure leaching,and the atmospheric nitric acid leaching(DNi process).The methods of recovering nickel,cobalt,scandium,and iron are emphatically outlined.Finally,reasonable suggestions are proposed for comprehensive utilization.This study can provide a reference for industrial development and diversified applications.

Family journey in the process of recovery of schizophrenia:A qualitative study

Objective:The aim of this research is to explore the life experiences of schizophrenic families in accompanying the recovery process.Methods:This study uses a qualitative method with descriptive phenomenology to explain phenomena from family experiences.The number of the participants was eight families who had family members with schizophrenia.Sampling was determined by purposive sampling.Data were collected through in-depth interviews and analyzed using the Colaizzi method.Results:The results of this study show four themes that emerged including(1)psychological burden on the family,(2)families needing support in the recovery process,(3)obstacles due to social stigma,and(4)family gratitude for being able to pass the test patiently.Conclusion:The schizophrenia family’s journey in the recovery process is very long.They are required to endure in assisting the recovery process.Experiences felt by the family include feelings,obstacles,and hopes that arise in carrying out their role to assist the recovery process which aims to improve the health of schizophrenia patients.The findings from this study provide insight for nurses to be able to pay attention to family psychological problems by strengthening families through home visits and health promotion related to the recovery process of survivor schizophrenia.

Preparation of single-phase ammonium dimolybdate by combination process

A novel method for the preparation of single-phase ammonium dimolybdate with industrial ammonium molybdate was studied. Various in- fluential factors were evaluated in the paper, including reaction temperature, reaction time, initial molybdenum concentration, initial NH_3 /Mo molar ratio, and stirring speed. Under the optimum experimental conditions, the crystallization rate of product is 85.23%. The X-ray diffraction (XRD) analysis and chemical analysis show that the product is single-phase ammonium dimolybdate, and no impurity phases exist. The scanning electronic microscope (SEM) image reveals uniform particle size, good particle dispersion, and no agglomeration between particles. Meanwhile, the final pH value of acidification was investigated. The total molybdenum recovery can reach up to 99.40%, and the main phases of acidification product are the same as those of raw material with the final pH value of 1.5. This determines that the acidification product can be used as a raw material to produce single-phase ammonium dimolybdate.

Recovery and regeneration of LiFePO_(4)from spent lithium-ion batteries via a novel pretreatment process

The recycling of spent LiFePO_(4)batteries has received extensive attention due to its environmental impact and economic benefit.In the pretreatment process of spent LiFePO_(4)batteries,the separation of active materials and current collectors determines the difficulty of the re-covery process and product quality.In this work,a facile and efficient pretreatment process is first proposed.After only freezing the electrode pieces and immersing them in boiling water,LiFePO_(4)materials were peeled from the Al foil.Then,after roasting under an inert atmosphere and sieving,all the cathode and anode active materials were easily and efficiently separated from the Al and Cu foils.The active materials were subjected to acid leaching,and the leaching solution was further used to prepare FePO_(4)and Li_(2)CO_(3).Finally,the battery-grade FePO_(4)and Li_(2)CO_(3)were used to re-synthesize LiFePO_(4)/C via the carbon thermal reduction method.The discharge capacities of re-synthesized LiFePO_(4)/C cathode were 144.2,139.0,133.2,125.5,and 110.5 mA·h·g−1 at rates of 0.1,0.5,1,2,and 5 C,which satisfies the requirement for middle-end LiFePO_(4)batteries.The whole process is environmental and has great potential for industrial-scale recycling of spent lithium-ion batteries.

A New Quenching Process and Tower to Improve the Recovery of Acrylonitrile

Quenching process and design of the quenching tower in acrylonitrile production in China were studied in order to decrease the polymerization loss of acrylonitrile in the quenching tower. Based on the research of acrylonitrile polymerization in the quenching tower, a new quenching process was proposed to avoid the disadvantages of the original process. Two kinds of internals were installed to improve the performance of the quenching tower. Through a series of air-flow and real-flow model experiments, the new quenching process and new design were showed to be successful in enhancing the mass and heat transfer in the vapor-liquid system and decreasing the loss of acrylonitrile.Industrial application showed satisfactory results of decrease of the acrylonitrile loss in the quenching tower by about 4.5% and increase of the acrylonitrile recovery of the whole plant by more than 4%.

Phase Transition in Recovery Process of Complex Networks

The dynamic characteristic of complex network failure and recovery is one of the main research topics in complex networks. Real world systems such as traffic jams and Internet recovery could be described by the complex network theory. We propose a model to study the recovery process in complex networks. Two different recovery mechanisms are considered in three kinds of networks： external recovery and internal recovery. By simulating the process of the nodes recovery in networks, it is found that the system exhibits the feature of first-order phase transition only when the external recovery is considered. Internal recovery cannot induce such a kind of transitions. As external recovery and internal recovery coexist on networks, the systems will retain the most efficient part of external recovery and internal recovery. Meanwhile, a hysteresis could be observed when increasing or decreasing the failure probability. Finally, a largest degree node protection strategy is proposed for improving the robustness of networks.

Hybrid low salinity water and surfactant process for enhancing heavy oil recovery

Combining low salinity water (LSW) with surfactants has an enormous potential for enhancing oil recovery processes. However, there is no consensus about the mechanisms involved, in addition to the fact that several studies have been conducted in model systems, while experiments with rocks and reservoir fluids are scarce. This study presents a core-flooding experiment of LSW injection, with and without surfactant, using the core and heavy oil samples obtained from a sandstone reservoir in southeastern Mexico. The effluents and the crude oil obtained at each stage were analyzed. The study was complemented by tomographic analysis. The results revealed that LSW injection and hybrid process with surfactants obtained an increase of 11.4 percentage points in recovery factor. Various phenomena were caused by LSW flooding, such as changes in wettability and pH, ion exchange, mineral dissolution, detachment of fines and modification of the hydrocarbon profile. In the surfactant flooding, the reduction of interfacial tension and alteration of wettability were the main mechanisms involved. The findings of this work also showed that the conditions believed to be necessary for enhanced oil recovery with LSW, such as the presence of kaolinite or high acid number oil, are not relevant.

Recovery of iron from copper tailings via low-temperature direct reduction and magnetic separation: process optimization and mineralogical study

Currently, the majority of copper tailings are not effectively developed. Worldwide, large amounts of copper tailings generated from copper production are continuously dumped, posing a potential environmental threat. Herein, the recovery of iron from copper tailings via low-temperature direct reduction and magnetic separation was conducted; process optimization was carried out, and the corresponding mineralogy was investigated. The reduction time, reduction temperature, reducing agent (coal), calcium chloride additive, grinding time, and magnetic field intensity were examined for process optimization. Mineralogical analyses of the sample, reduced pellets, and magnetic concentrate under various conditions were performed by X-ray diffraction, optical microscopy, and scanning electron microscopy-energy-dispersive X-ray spectrometry to elucidate the iron reduction and growth mechanisms. The results indicated that the optimum parameters of iron recovery include a reduction temperature of 1150A degrees C, a reduction time of 120 min, a coal dosage of 25%, a calcium chloride dosage of 2.5%, a magnetic field intensity of 100 mT, and a grinding time of 1 min. Under these conditions, the iron grade in the magnetic concentrate was greater than 90%, with an iron recovery ratio greater than 95%.

Thermal recovery process of a backfilled open-pit in permafrost area at the Gulian strip coal mine in Northeast China

Timely and proper backfilling of open-pits in strip coal-mines has been an effective measurement for the recovery of the hydrothermal regimes and ecological environment in permafrost regions. In this study, numerical simulations and statistical regressions were applied for analyzing the recovery processes of the backfill and its major influencing factors for the thermal equilibrium in recently backfilled open pits at the Gulian strip coalmine in Mo'he, Northeast China. Results show that the thermal recovery time of backfilled areas is positively correlated to the backfill depth(BD) of the soils, the backfilled soil temperature(BST), and the mean annual ground surface temperature(MAGST); meanwhile, climate warming can impact on thermal regimes of the backfill area. The impact of climate warming on ground temperature of the backfill will show up significantly in about 50 years afterbackfilling(BD at 10.0 and 20.0 m, BST at 20.0°C) under the climate warming scenario(CWS) of 0.025°C·year ^(-1). Grey-relation analyses show that the sensitivity of the backfill recovery time declines in the order of the BD, BST and MAGST. On the basis of the abovementioned studies, the layer-by-layer backfilling in cold seasons is advised for more effective and more rapid recovery of thermal regimes of the backfilled open-pits in cold regions.

Copper Recovery from Barren Cyanide Solution by Using Electrocoagulation Iron Process

This paper is a brief overview of the role of inducing the nucleated electro winning of copper by using iron electrodes in electrocoagulation (EC) process. Cyanide compounds are widely used in gold ore processing plants in order to facilitate the extraction and subsequent concentration of the precious metal. Owing to cyanide solution employed in gold processing, effluents generated have high contents of free cyanide as well as copper cyanide complexes, which lend them a high degree of toxicity. In this regard, two options for the treatment of cyanide barren solutions has been used;in two ways;first for cyanide destruction by oxidation with the use of the EC process, in theory, has the advantage of decomposing cyanide at the anode and collecting copper simultaneously by a sludge of copper magnetic iron. In both cases excellent performance can be achieved using the high capacity of the bipolar iron EC technology. We found that it is possible to reduce the copper cyanide complex from 720 mg·l-1 to below 10 mg·l-1 within 20 minutes.

Polymer/Ceramic Composite Membranes and Their Application in Pervaporation Process

Pervaporation(PV),as an environmental friendly and energy-saving separation technology,has been received increasing attention in recent years.This article reviews the preparation and application of macroporous ceramic-supported polymer composite pervaporation membranes.The separation materials of polymer/ceramic composite membranes presented here include hydrophobic polydimethylsiloxane(PDMS) and hydrophilic poly(vinyl alcohol)(PVA),chitosan(CS) and polyelectrolytes.The effects of ceramic support treatment,polymer solution properties,interfacial adhesion and incorporating or blending modification on the membrane structure and PV performance are discussed.Two in-situ characterization methods developed for polymer/ceramic composite membranes are also covered in the discussion.The applications of these composite membranes in pervaporation process are summarized as well,which contain the bio-fuels recovery,gasoline desulfuration and PV coupled proc-ess using PDMS/ceramic composite membrane,and dehydration of alcohols and esters using ceramic-supported PVA or PVA-CS composite membrane.Finally,a brief conclusion remark on polymer/ceramic composite mem-branes is given and possible future research is outlined.

Mineral Processing of Silica Sand in Hanout Area/South of Jordan

White sandstone samples from Hanout area of Late Cambrian-Early Ordovician sandstone in south of Jordan were studied and assessed as a source of glass sand. Upgrading the sand included removing or reducing the content of the contaminant oxides and the heavy minerals. The aim of this research was to achieve this upgrading by examining the best-suited and cost-effective processing method(s) with sufficient product recovery. Following the initial sample characterisation at “bench scale”, a pilot study was performed. A high-grade Glass Sand product of 500 - 125 μm size fraction was produced by wet screening, attrition scrubbing and the separation of heavy minerals using spirals. The high quality Glass Sand product compared well with Grade-A of the British Standard for glass sand. Due to the relatively low level of impurities in the raw material, a substantial silica sand recovery was produced with a high silica grade. The silica sand product was capable to be used in the high quality glass industry and in many other applications where pure silica is required. The mass flowrate of the feeds and the products in the spiral was calculated for the bulk sample as well as the amount of water required operating the process.

Sustainabilty of Rice Processing in Rural Sub-Saharan Africa

Energy and environmental sustainability are important considerations for increased rice production. This study examined the energy utilization and sustainability of rice processing in sub-Saharan Africa. The community of Gadan Loko village in the song local government of Adamawa State, Nigeria was selected as the focus of study. Rice parboiling, the most energy intensive process in rice processing is carried out usually by women in small quantities of about 13.2 kg using traditional pots on tripod support stoves. The parboiled rice is sun dried on mats before it is taken to the milling stalls where it is milled using milling machines driven by single cylinder diesel engines. There were large variations in the quality of milled rice due to lack of consistency in processing parameters. Accumulation of rice husk in the community created important environmental issues. In this study, methods of improving sustainability of rice processing were investigated. The areas included： the utilization of waste heat from the diesel engines for improved drying and efficient pre-soaking; the utilization of solar energy for pre-soaking; the utilization of rice husks as alternative fuel to firewood; and the optimization and redesign of the stoves and parboiling vessels to minimize heat loss to the environment. The results showed that the utilization of rice husk as alternative fuel and the redesign of the stoves and parboiling vessels will increase the sustainability of rice processing and can be easily adopted by the community. While solar energy pre-soaking was not economical and the utilization of waste heat from the diesel engines for drying and pre-soaking would be difficult to implement at the rural scale, because most of the parboiling is done far away from the milling stalls. The study showed that research, development of appropriate technology, and education （RATE） of the rural community is an important way of increasing sustainability.

Flow curve correction and processing map of 2050 Al-Li alloy

Hot compression tests of 2050 Al-Li alloy were performed in the deformation temperature range of 340-500°C and strain rate range of 0.001-10 s-1 to investigate the hot deformation behavior of the alloy.The effects of friction and temperature difference on flow stress were analyzed and the flow curves were corrected.Based on the dynamic material model,processing map at a strain of 0.5 was established.The grain structure of the compressed samples was observed using optical microscopy.The results show that friction and temperature variation during the hot compression have significant influences on flow stress.The optimum processing domains are in the temperature range from 370 to 430°C with the strain rate range from 0.01 to 0.001 s-1,and in the temperature range from 440 to 500°C with the strain rate range from 0.3 to 0.01 s-1;the flow instable region is located at high strain rates(3-10 s-1)in the entire temperature range.Dynamic recovery(DRV)and dynamic recrystallization(DRX)are the main deformation mechanisms of the 2050 alloy in the stable domains,whereas the alloy exhibits flow localization in the instable region.

Europium recovery process by means of polymeric nanoparticles functionalized with acrylic acid,curcumin and fumaramide

Polymeric nanoparticles of poly(methyl methacrylate)were obtained by emulsion polymerization techniques in a proce ss of two stages.The particles were functionalized with acrylic acid,curcumin,and fumaramide and three series of polymeric particles were obtained.The incorporation of functional groups was confirmed by Fourier transform-infrared spectrosocopy(FT-IR)and ultraviolet-visible(UV-Vis)methods.The spherical morphology of particles with an average diameter of 100 nm was observed by scartning electron microscopy(SEM).The polymeric materials were used for recovery of[Eu]from synthetic solutions.The nanoparticles show excellent chelation capacity to trap rare-earth ions,because they recover more than 85%of[Eu]at pH of 2.The images of SEM after extraction process show arrays between particles with larger average particle sizes to 1.5 um.In addition,the particles have a good stripping capacity,exceeding 50%of it,maintaining their homogeneity in morphology and good stability in dispersion for the recovery and stripping processes.A pseudo-second model order is obtained for the extraction and stripping processes while the best results of stripping process are obtained at pH of 6.

Disaster Recovery and Reconstruction Following the 2011 Great East Japan Earthquake and Tsunami: A Business Process Management Perspective

The Tohoku Regional Bureau(TRB) of the Ministry of Land, Infrastructure, Transport and Tourism(MLIT) performed various actions in response to the 2011 Great East Japan Earthquake and Tsunami. The total disaster recovery and reconstruction period is expected to last for 10 years, of which the first five years are regarded as the concentrated reconstruction period. As of 2013, a majority of the mega projects that involved restoration actions have been completed, which indicates a more effective rate of completion compared with the MLIT projects performed in normal non-disaster situations. This short article explains the management process of the recovery and reconstruction utilized by the TRB—an interorganizational process—from a business process management(BPM) perspective and creates a simple organization construction diagram of the entire process. The study focused on the transactions and actor roles to identify their strengths. The findings indicate the utilization of different operational procedures in some parts of the process, the importance of liaison role, as well as some obstacles. The lessons learned from this analysis can assist managers and researchers in designing and managing restoration processes for future disasters.

Emerging electrochemical processes for materials recovery from wastewater: Mechanisms and prospects

Recovering valuable materials from waste streams is critical to the transition to a circular economy with reduced environmental damages caused by resource extraction activities.Municipal and industrial wastewaters contain a variety of materials,such as nutrients(nitrogen and phosphorus),lithium,and rare earth elements,which can be recovered as value-added products.Owing to their modularity,convenient operation and control,and the non-requirement of chemical dosage,electrochemical technologies offer a great promise for resource recovery in small-scale,decentralized systems.Here,we review three emerging electrochemical technologies for materials recovery applications:electrosorption based on carbonaceous and intercalation electrodes,electrochemical redox processes,and electrochemically induced precipitation.We highlight the mechanisms for achieving selective materials recovery in these processes.We also present an overview of the advantages and limitations of these technologies,as well as the key challenges that need to be overcome for their deployment in real-world systems to achieve cost-effective and sustainable materials recovery.

Remembering,Forgetting,and Absencing Disasters in the Post-disaster Recovery Process

Sustainable post-disaster recovery implies learning from past experience in order to prevent recreating forms of vulnerability.Memory construction supports both the healing process and redevelopment plans.Hence,memory of disaster results from the balance between remembering,forgetting,and absencing elements of the disaster,and can be both a tool and an obstacle to sustainable recovery.We explore here how collective memory is built in a post-disaster context to respond to the needs of this critical period,and how it shapes recovery.This ethnographic study,conducted between 2015 and 2017,explores the recovery processes in Montserrat,a small Caribbean island affected by an extended volcanic crisis from 1995 to 2010.Although this study does not give tangible solutions for disaster risk reduction in a post-disaster context,it highlights potential obstacles for learning from a disaster and how they may be surmounted.We argue that it is crucial to acknowledge evolving collective memory in order to implement effective measures for preserving and sharing a shared understanding of disaster across generations and social groups in a way that supports disaster risk awareness.We also maintain that acknowledging the dilemma faced by authorities and disaster management agencies during a period of conflicting needs may encourage the reconsideration of risk framing,and hence reveal how to improve implementation of disaster risk reduction measures.

The influence of desiccation on the recovery process of nitrogenase activity in restored biological soil crusts

Dear Editor,Biological soil crusts(BSCs),a layered structure formed by associations of soil organisms and topsoil,dominate arid and semiarid areas and serve important ecological functions in these areas(Eldridge and Greene,1994).Nitrogen fixation by BSCs is the main source of N in arid and semi-arid ecosystems.Desiccation is the most notable factor that influences BSCs,which recover physiological activity only after moistening.By influencing the amount of carbohydrates,

Multistate Models for the Recovery Process in the Covid-19 Context:An Empirical Study of Chinese Enterprises

The Covid-19 pandemic has severely affected enterprises worldwide.It is thus of practical significance to study the process of enterprise recovery from Covid-19.However,the research on the effects of relevant determinants of business recovery is limited.This article presents a multistate modeling framework that considers the determinants,recovery time,and transition likelihood of Chinese enterprises by the state of those enterprises as a result of the pandemic(recovery state),with the help of an accelerated failure time model.Empirical data from 750 enterprises were used to evaluate the recovery process.The results indicate that the main problems facing non-manufacturing industries are supply shortages and order cancellations.With the increase of supplies and orders,the probability of transition between different recovery states gradually increases,and the recovery time of enterprises becomes shorter.For manufacturing industries,the factors that hinder recovery are more complex.The main problems are employee panic and order cancellations in the initial stage,employee shortages in the middle stage,and raw material shortages in the full recovery stage.This study can provide a reference for enterprise recovery in the current pandemic context and help policymakers and business managers take necessary measures to accelerate recovery.