Gravity Separation Research Articles

An Innovative Magnetic Density Separation Process for Sorting Granular Solid Wastes

Solid waste sorting is an important pre-treatment in recycling to improve the efficiency of material recovery and reduce costs. Motivated by the PEACOC project on metal recovery from solid wastes, an innovative magnetic density separation (MDS) process has been developed for solid waste sorting. It has intrinsic advantages over conventional gravity separation technologies and the previously industrialized MDS process. The new MDS process applies an inclined planar magnet and a horizontal basin containing a static magnetic fluid as the separation medium. A particle sliding phenomenon is identified as a feature that could help the separation. Experiments have been carried out to demonstrate the role of the MDS in concentrating valuable metals in shredded PCBAs and reducing metallic contaminants in plastic fractions of shredded wires. A pilot scale facility is introduced to show the design to achieve continuous production and to reduce the consumption of ferrofluid.

Design of downhole oil-water separation device and study on separation mechanism based on rod pump heavy oil system

Abstract Downhole oil-water separation technology (DOWS) is a new type of separation technology, which can improve efficiency, reduce energy consumption, and can solve the problem of high water cut oilfield development. At present, there are only two separation methods in the same well injection-production separator, one is the swirl separation technology and the other is the gravity separation technology. Cyclone separation technology mainly relies on cyclone separators to separate oil and water, but it is affected by oil viscosity, water content, and temperature. The gravity separation technology mainly relies on the similar separation principle of a multi-cup equal-flow gas anchor to design a multi-cup equal-flow oil-water separator, but it requires the oil-water mixed production liquid to stay in the settling bowl for a long time. The centrifugal separator has the characteristics of a good separation effect, high efficiency, and low demand for oil. At present, the downhole centrifugal separator is not used in the same well injection-production technology, which mainly needs to solve the driving force problem of the centrifugal separator. The new injection-production device designed in this paper can better solve the driving problem of the centrifugal separator and meet the working requirements of the process.

UiO-66-NH2/hydrothermal carbon nanocomposite assembled mesh membrane with photocatalytic self-cleaning and antibacterial properties for on-demand oily wastewater separation

The poor wettability, limited permeation flux and unsatisfactory anti-fouling property of oil/water separation membranes significantly hinder their practical application. This study developed a novel UiO-66-NH2/hydrothermal carbon@stainless steel mesh (UiO/HC@SSM) membrane, fabricated through a straightforward dip-coating strategy that offers membrane thickness control. The resulting membrane exhibited superhydrophilic/underwater superoleophobic property and high porosity, enabling gravity-driven separation of emulsified and stratified oil/water mixtures on-demand with high separation efficiency and superior flux. Specifically, UiO/HC@SSM-5 (dip-coating five times) showed ultrahigh permeate fluxes of 51428–56425 L m−2 h−1 for stratified oil/water mixtures separation, and UiO/HC@SSM-10 exhibited interface demulsification and gravity separation ability for emulsified oil/water mixtures with high fluxes of 4050–4504 L m−2 h−1. Notably, UiO/HC nanocomposite endowed the membrane with exceptional photocatalytic self-cleaning and antibacterial activities, effectively addressing both oil and microbial fouling. High-viscosity crude oil fouling can be light-induced decontaminated from the composite membrane surface with superior flux recovery ratio (FRR) up to 97 %. The as-prepared UiO/HC@SSM also exhibited near-complete bacterial inactivation activity after 10 min of visible light irradiation. Encouragingly, UiO/HC@SSM demonstrated superior separation and photocatalytic capabilities compared to UiO@SSM, attributed to the dual promoting role of cost-effective hydrothermal carbon in hydrophilicity and photoelectric properties. Moreover, UiO/HC modified SSM membrane displayed robust chemical and mechanical stability, coupled with superior harsh environments and oil pressure resistances. This membrane, boasting desirable wettability, high permeability, exceptional photocatalytic activity, and excellent stability, offers a reliable solution for treating complex oily wastewater. Additionally, the demulsification and photocatalysis mechanisms of UiO/HC@SSM membrane were examined in depth. This study holds significant potential in advancing the development of novel SSM membranes functionalized with MOF/carbon material, thereby enhancing their practical applications in purifying oily wastewater.

Influence of Mineralogy and Mineralogy Approach to Optimize Processing: A Case Study of Tin–Copper Polymetallic Ore

Tin-Copper polymetallic ore is a type of typical ore that cassiterite is closely associated with sulfide minerals. In mineral processing of tin–copper polymetallic ore, flotation is generally used to recover valuable sulfide minerals, while gravity separation is used to recover cassiterite. A mine in Yunnan, China, uses the traditional “flotation–gravity separation” process to recover copper and tin but faces several problems during processing, such as an insufficient copper grade in Cu concentrate, a much higher grade of As in S concentrate, and a grade of S in Sn concentrate that exceeds the standard. A process mineralogy study was conducted, with a focus on Cu–S mixed concentrate, S concentrate, and Sn rough concentrate. It was determined that the main cause of these problems is not the liberation or size distribution of valuable minerals but the superstructure of pyrrhotite, which represents one of the most abundant minerals in the products. Based on EMPA, SEM-EDS, and XRD data, both monoclinic pyrrhotite and hexagonal pyrrhotite occurred in all samples. The abundance of different superstructures of pyrrhotite in one sample was determined by means of particle extraction and area calculation from microscopic images, and the distribution characteristics of monoclinic pyrrhotite and hexagonal pyrrhotite in the whole process were clarified. This process mineralogy study indicates that the strong magnetic hexagonal pyrrhotite mainly affects the copper recovery during flotation, and the hexagonal pyrrhotite mainly affects the recovery of cassiterite during gravity separation. Strong magnetic monoclinic pyrrhotite and weak magnetic hexagonal pyrrhotite should be fully considered in the optimization of mineral processing, and the magnetic separation of pyrrhotite should be adopted to optimize the overall environment of copper flotation and tin gravity separation.

Analysis of remaining life assessment of three-phase gravity separator for oil rectification with the simultaneous usean RBI matrix

The paper presents a detailed description of the oil rectification process used in upstream oil and gas plants, including the significant equipment involved. One such equipment highlighted in the study is a pressure vessel utilized as a separator to separate the liquid and gas phases. This pressure vessel has been in operation for over two decades. A thorough examination of the mentioned pressure equipment was conducted during the process evaluation. It was discovered that the internal side of the vessel, particularly its back elliptical head, had suffered extensive damage due to erosion and corrosion, emerging as the most significant cause of the deterioration. The application of RBI-estimation revealed that the vessel falls under the category of highly risk equipment, and there is a significant risk of both environmental and financial consequences associated with its potential failure (leakage). Such failure is anticipated to occur promptly in the area below the wear plate of the vessel's nozzle.

The multi‐stage gasification process of low‐rank coal samples from gravity separation process

AbstractThe separation process is a well‐established method for beneficiation technologies of low‐rank coal, especially in the case of utilization in the thermochemical processes. In this study, three coal samples, including the original low‐rank coal sample and two coal samples (C1 and C2) from the gravity separation process of the original coal sample, were gasified in a multi‐stage gasification process at the gasification temperature of 900°C and the steam‐to‐carbon (S/C) ratio of 1.00 and 1.25. The separation process led to a significant improvement in the quality of coal samples. This improvement is particularly characterized by a higher carbon and volatile fractions and a lower ash content compared with the original coal. This could be the main reason for the higher gasification performance in the case of the experiment of C1 and C2 coal samples. The volume of syngas obtained from gasification experiments of C1 and C2 samples increased between 1.3 and 1.5 times that of the original coal sample. At all S/C ratios and 900°C, the gasification experiment of the C2 sample produced the highest produced gas yield followed by the gasification experiment of the C1 sample. From the chemical point of view, the produced gas had an H2/CO ratio close to the desired ratio of 2.00, which is suitable for chemical synthesis processes. In the case of C1 sample experiments, the H2/CO ratios were 2.11 and 2.18 at S/C ratios of 1.00 and 1.25, respectively. For the experiments of the C2 sample, the H2/CO ratio reached 1.88 and 2.00 at S/C ratios of 1.00 and 1.25, respectively.

Dynamic Modelling and Simulation of A Three-Phase Gravity Separator

Many studies have investigated the crude oil separation process’s separation mechanisms, size, and design, employing horizontal 3-Phase Gravity Separators in depth. There are, however, very few articles on their dynamics, modelling, and simulation. Understanding its dynamic behaviour will aid in designing and tuning the device that can manage water level, oil level, and gas pressure in response to feeding variations. This Scientific Paper gives a complete mathematical analysis, modelling, and simulation of a crude oil separation process using a horizontal 3-Phase Gravity Separator using Mathworks Matlab R2016b-x64 and Aspen Hysys V10. Bishoy’s Equations, which were constructed, will assist in operating this gadget, locating various variables, and observing the effect of modifying variables on the system’s variables. The rationale for this study was developed in response to the small number of articles discovered, which may be a covert issue held up by large oil companies, as well as the complicated equations related to this process that remain unsolved, and to monitor what is happening in this complex dynamic process. As a result, this Research Paper is unique and novel, and it can be compared to the work done by some authors who did not solve the obtained differential equations and did not go further in Aspen Hysys Modeling and Simulation, whereas this paper provides everything related to a three-phase gravity separator, including changing of variables and observing the effect on the system when those variables were modified. Furthermore, separators are designed with internal baffles to promote laminar flow and increase separator efficiency. However, it has been assumed that there are no baffles here, which is a significant problem, but with the help of these equations, the horizontal three-phase gravity separator can be operated at its maximum efficiency. The equations determined the following variables: The height of gas, water, oil, the height of oil when it jumped the weir, the pressure of the gas (in and out), water pressure (in and out), oil pressure (in and out), and the effect of increasing (control valve’s stem position) and decreasing Qin (inlet volumetric flowrate) on these variables have all been studied. This article discovered that increasing the control valve stem position and decreasing the inflow volumetric flowrate of both oil and water was highly unsafe and caused significant variations in the system’s heights and pressures using Matlab. The Aspen Hysys analysis optimally separates the oil, gas, and water to determine material, energy streams properties, and compositions. As a result, this complex dynamic behaviour was observed, and no additional articles were discovered that addressed this subject. This process monitoring will determine the best conditions for flawless separation, with the selectivity of the desired product or products as the primary goal. This research can revolutionize the way people think about oil and gas extraction and processing and benefit colossal oil and gas firms in Europe, Asia, and Africa.

Efficient oil–water emulsion separation using chitosan hydrogel-coated aluminium electrodes

ABSTRACT The escalating consumption of crude oil, driven by rapid industrialization, poses a significant threat to terrestrial and marine ecosystems. Addressing the treatment of oily wastewater is imperative, given the environmental consequences and the loss of oil feedstock. Methods such as centrifugation, gravity separation, and chemical–physical membrane separation have limitations in handling stable emulsions, especially microemulsions present in water. In this study, we present an innovative approach utilizing electricity for the coagulation process. Electrocoagulation is employed, and the resulting oil particles are efficiently removed through low-tech physical methods such as sedimentation and filtration. To enhance efficiency and reusability, we introduce chitosan hydrogel-coated aluminium electrodes in the electrocoagulation process. The research demonstrates remarkable success, achieving a 99% efficiency in separating artificial oil–water emulsions. Optimal separation (95.85%) is achieved at a 10 mm inter-electrode distance, and efficiency increases with higher oil content, longer electrocoagulation time (up to 99.15% at 60 min), and increased voltage (up to 85% at 50 V). The chitosan-coated electrodes offer a sustainable and cost-effective solution by improving reusability and mitigating the need for frequent changes. These findings underscore the significance of electrocoagulation, particularly with chitosan-coated aluminium electrodes, as an efficient and eco-friendly method crucial for addressing oil removal in industrial processes.

Economic heavy minerals in the stream sediments of wadi Shaàb, southern coast of the Red Sea, Egypt; characterization and upgrading for investigation of their potential recovery

The southern coast of the Red Sea is one of the most promising areas for the occurrence of economic minerals. Therefore, studying the characterization and evaluation of these minerals in the Wadi Shaàb Quaternary sediments and investigating their ability to concentrate and physically separate using economical and ecofriendly techniques is the main goal of this work. The results showed that the representative sample contains an average of 0.06% ilmenite, 0.08% zircon, 0.07% rutile, 0.07% leucoxene, 0.008% cassiterite, 0.004% xenotime, 0.0004% monazite, 0.022% almandine garnet, and 0.46% magnetite. The recovery of economic heavy minerals was applied using a combination of wet-gravity technique via shaking table and magnetic separation using high intensity magnetic separator. The results demonstrated the success of gravity separation in raising the grade from 7.63% to 45.03% in a yield of 13.74% out of the original sample, and also valuable metallurgical recoveries that greater than 89% for tabling multi-stages (rougher and scavenging) was obtained. Concentrated mineral fractions of magnetite, ilmenite, almandine, heavy silicates, and the non-magnetic fraction bearing zircon and rutile were obtained using a high intensity magnetic separator at different ampere range

Pre-concentration of REE values from nepheline syenite rocks of western Odisha, India

ABSTRACT The rare-earth elements (REEs) have gained enormous economic and scientific attention due to their distinct properties and new applications. Nepheline syenite rock is an important primary source of rare earth minerals. The nepheline syenite rocks from the Rairakhol area, western Odisha, have been characterized for their rare earth mineralogical and textural characteristics. Preliminary beneficiation studies of these rocks were carried out to upgrade the REE values using falcon gravity separation and floatation technique. Hornblende, biotite, K-feldspar, albite, and nepheline are the major mineral constituents of the nepheline syenite where REE-bearing minerals occur as accessory minerals. The REE mineral phases present are zircon, sphene, apatite, allanite, britholite, and REE phosphate, with grain sizes ranging from 10 to 50 microns. Allanite and britholite occupy the intergranular spaces of major mineral phases and occur as thin lines or veins whereas sphene and zircon occur as inclusions within major mineral phases. The flotation study shows that the total REE content of the froth product could be enriched to 1696 ppm, which is three times more than the total REE content (563 ppm) of the feed sample.

Bastnaesite Beneficiation by Froth Flotation and Gravity Separation

Bastnaesite Beneficiation by Froth Flotation and Gravity Separation

Characterizing low-grade refractory gold ores using automated mineralogy coupled with LA ICP-MS

Researchers have made notable progress in quantifying refractory components causing gold losses in traditional extraction methods. The potential for improving gold recoveries lies in targeted re-treatment of the 'invisible' gold fraction hosted within various ore minerals, even at low concentrations. This study presents a methodology for analysing the refractory components that cause gold losses in traditional extraction methods. The approach utilizes automated mineralogical techniques in conjunction with in-situ laser ablation inductively coupled plasma mass spectrometry (LA ICP-MS) to characterize low-grade refractory ores and assess gold deportment. The methodology combines pre-concentration gravity separation, traditional chemical and mineral techniques, and LA ICP-MS to generate comprehensive datasets. To demonstrate the practical application of the methodology, a case study was conducted on historical tailings material from Witwatersrand's Evander Goldfield in South Africa. The case study aimed to determine the mineralogical distribution of gold that cannot be extracted through cyanidation. The results indicated that invisible gold is primarily hosted in pyrite (with an average concentration of 10.21 ppm representing 32 % of total gold), other sulphides (with an average concentration of 1.29 ppm representing 0.42 % of total gold), and oxides (with an average concentration of 0.50 ppm representing 1 % of total gold). The remaining gold is present in discrete fine cyanide amenable phases (with 28 % deportment) and silicate-hosted phases (with 39 % deportment). Environmental monitoring of the Witwatersrand tailings material revealed a net “acid-producing” nature, with high concentrations of heavy metals (such as As, Cu, Pb, Mn, Hg, and Ni) associated with sulphides (with over 78 % deportment). The deportment information obtained through this approach can optimize ore processing strategies and provide valuable insights for future remediation plans. By characterizing the refractory components causing gold losses and understanding the distribution of gold within the ore, this methodology offers the potential to enhance gold recovery and improve the efficiency of ore processing operations.

Robust Adaptive Control of the Offshore Produced Water Treatment Process: An Improved Multivariable MRAC-Based Approach

The application of deoiling hydrocyclone systems as the downstream of three-phase gravity separator (TPGS) systems is one of the most commonly deployed produced water treatment processes in offshore oil and gas production. Due to the compact system’s complexity and tailor-made features, it is always challenging to develop some optimally coordinated control solution for the coupled hydrocyclone and TPGS systems. It is obvious that coordinated control can better fulfill legislative discharge regulation by robustly maintaining high separation efficiencies. This paper presents a new control solution for a set of integrated hydrocyclone and TPGS systems by applying an improved multi-variable model reference adaptive control (MV-MRAC) approach with the aim of achieving both asymptotic output tracking and unknown disturbance rejection. A robust MV-MRAC controller design is proposed based on a control parameterization derived from a factorization of a high-frequency gain matrix Kp=LDS as a product of three matrices, where L represents unity lower triangular, D=sign(D) represents diagonal, and S represents positive definite, and a teaching–learning-based optimization (TLBO) algorithm for optimizing the adaption rates. The developed solution is analyzed and compared with a commonly deployed PI control solution on a model that is derived from a lab-scale produced water treatment process. This simulation study demonstrates the promising potential of the proposed control solution compared with the currently deployed PI control solution.

Investigating the Gravity Beneficiation Consequence on Farin-Lamba (Plateau State) Cassiterite towards Tin Oxide Production

This research aims to assess the amenability of Farin-Lamba cassiterite to the gravity concentrations techniques towards tin oxide production. The ore was subjected to fractional sieve size analysis, work index, and the concentration test to gravity method using the Wilfley shaking table and Spiral concentrator processing. Fractional sieve analysis of the crude sample was carried out at a sieve range of 500-63 µm towards liberation size determination. Five hundred (500) g each of Farin-Lamba cassiterite and Igbokoda silica sand was prepared by grinding to 100% passing 500 μm sieve towards work index determination and the gravity separation method was determined using the Wilfley shaking table and spiral concentration method. The fractional sieve size analysis carried out revealed that the Tin oxide-bearing mineral can be liberated at the particle size fraction of -180 + 125 μm. The work index alongside the energy expended in grinding the ore was found to be 9.980 Kwh/ton and 2.435 Kwh respectively. The chemical analysis of the ore concentrates revealed that the optimum yield was obtained at +125 µm assaying 62.74% SnO2 for Wilfley shaking table and 60.07% SnO2 for spiral concentration.

Начальный этап разработки математической модели для управления процессом магнитно-гравитационной сепарации в режиме реального времени

The initial stage of the mathematical model development designed to control in real time the enrichment of magnetite ores in magnetic gravity separators is presented the article. A significantly lower computational complexity in comparison with models using computational fluid dynamics tools is a main requirement for the created model. The study uses physical modeling and applies similarity criteria which well-known in hydrodynamics. As a result of processing of the laboratory experiments data, the structure of the model was established, the values of its parameters for boundary cases were obtained and the directions of further research on improving the model were determined.

Comprehensive Study on Mineral Processing Methods and Mineral Technical Economics of Manganese Ore in Chongqing Chengkou.

Chongqing Chengkou manganese deposit is a large carbonate-type manganese deposit in the upper reaches of the Yangtze River, located in Gaoyan Town, Chengkou County, Chongqing. In order to improve the recovery rate of low-grade manganese ore and concentrate grade index, achieve efficient utilization of mineral resources, and sustainable development of Gaoyan manganese ore deposit in Chengkou, Chongqing, China, in this paper, by means of optical microscope analysis, high-resolution X-ray tomography technology, three-dimensional image analysis technology, X-ray diffraction analysis, X-ray fluorescence spectrum analysis, and technical and economic analysis, the occurrence state and process mineralogy of manganese are studied, and the technical and economic analysis of flotation, high-intensity magnetic separation, and gravity separation are carried out. It provides a reference for other mining enterprises to choose the most suitable beneficiation method according to the specific mineral species.

Design and Fabrication of Gravity Separator for Grains and Dust

Gravity separators are machines used to separate grains and dust by using the difference in weight between grains and dust. They work by causing grains to fall at different speeds, with heavier grains falling faster and lighter dust falling slower. The new gravity separator design is more efficient and effective than previous designs, making it easier to clean and maintain. It has the potential to revolutionize the separation process, saving businesses time and money. The new gravity separator is more effective at separating grains from dust and other impurities, improving the quality of food products and mined minerals. Additionally, it is also reducing waste.

Research on extraction of carbon from coal gasification fine slag using hydrophobic-hydrophilic separation: Efficient separation, molecular dynamics simulation, and model optimization

Disposing of coal gasification fine slag (CGFS) in piles and landfills result in enormous resource wastage and potential environmental risks. The precondition for CGFS resource utilization is separating residual carbon and ash materials. However, froth flotation products are heavily entrained, and gravity separation is not targeted for fines. This research introduced Hydrophobic-Hydrophilic Separation (HHS) as a solution to achieve efficient separation of residual carbon and ash materials. We investigated the surface morphology, elemental composition, and functional group species of residual carbon and ash materials by various testing methods. Additionally, molecular dynamics simulations were employed to reveal the visualization mechanism of CGFS in HHS. Response surface methodology analyzed the effects of mixing time, stirring speed, and n-heptane dosage on HHS carbon/ash separation. Furthermore, the sequence and interaction relationships of factor effects were analyzed, and optimal parameter values were determined. The advantages of HHS over froth flotation and gravity separation were briefly discussed. Finally, research directions were proposed for the process design of HHS and resource utilization with HHS products. This research would provide the theoretical basis and technical support for the efficient separation of residual carbon and ash materials, the large-scale resource utilization of CGFS, and the high-value processing of HHS products, which was beneficial to clean production, sustainable development, and environmental management.

Gravity-based pre-concentration strategies for complex rare earth ore containing niobium and zirconium

The Balzhe rare earth mine, renowned for its rich reservoirs of niobium, zirconium, and rare earth elements, poses a unique challenge due to its diverse and interbedded mineral composition. Despite the abundance of these elements, their valuable grade remains notably low, falling short of economic thresholds. To this end, pre-concentration of valuable minerals to discard gangue minerals before flotation would be an economical option. In response, this study delves into the feasibility of gravity-induced pre-concentration, aiming to segregate valuable minerals from gangue for subsequent flotation processes. Conducting float-and-sink tests on varied particle sizes (-2+0.5 mm, -0.5+0.074 mm, and -0.074+0.02 mm) within heavy liquids of specific gravities (ranging from 2.55 to 2.85), the study reveals the effectiveness of gravity separation. Notably, particles sized -2+0.5 mm and -0.074+0.02 mm demonstrated superior separation performance over the -0.5+0.074 mm fraction. Comparative analysis of diverse gravity separation equipment unveiled compelling results. The dense medium cyclone separator showcased impressive recovery rates and high-grade concentrates of Nb<sub>2</sub>O<sub>5</sub>, ZrO<sub>2</sub>, and total rare earth oxides (TREO) at 0.34%, 8.20%, and 0.41%, respectively, surpassing the sand table's performance for -2+0.5 mm particles. Conversely, for -0.5+0.074 mm particles, the shaking table exhibited optimal separation efficiency, yielding grades of Nb<sub>2</sub>O<sub>5</sub>, ZrO<sub>2</sub>, and TREO at 0.37%, 4.08%, and 0.44%, with substantial recovery values. Ultimately, the Knelson centrifugal separator proved most effective for -0.074+0.02 mm particles, yielding notable grades and recoveries of Nb<sub>2</sub>O<sub>5</sub>, ZrO<sub>2</sub>, and TREO. This study underscores the promising potential of gravity-induced pre-concentration techniques for enhancing the recovery of valuable elements from the complex Balzhe rare earth ore, offering critical insights into optimizing mineral extraction processes.

Classification Evaluation Method Considering the Effect of Specific Gravity Sorting in Air Classification—Case Study of Solar Panel Cell Sheets Classification—

Classification Evaluation Method Considering the Effect of Specific Gravity Sorting in Air Classification—Case Study of Solar Panel Cell Sheets Classification—