Gravity Separation Process Research Articles

Tellurium Enrichment in Copper Tailings: A Mineralogical and Processing Study

As the global demand for tellurium (Te) increases, it is crucial to develop efficient recovery methods that consider existing supply streams. This research combines gravity separation and froth flotation processes to enhance the recovery of Te minerals from tailings produced during the beneficiation of copper porphyry ores. Prior to processing, a systematic and comprehensive characterization study of copper tailing (CT) samples was conducted to examine the deportment of Te minerals in different mineral phases and to understand their locking and liberation behavior. Characterization techniques included inductively coupled plasma mass spectrometry (ICP-MS) and TESCAN’s integrated mineral analysis (TIMA). Copper tailing characterization showed that minerals with gold (Au), silver (Ag), bismuth (Bi), and Te were present in various forms, including native Au, electrum, tellurides, and sulfosalts. TIMA revealed that >90% of these minerals were primarily hosted in pyrite as less than 10 µm inclusions in the CT. TIMA also revealed that Te minerals exhibited fine-grained liberation of less than 20 μm. Moreover, TIMA results showed that >80% of mica and other silicate minerals were concentrated in size fractions < 38 μm, suggesting that desliming processes would positively impact Te enrichment. The results from the processing tests showed a Te recovery rate of ~77% and a Te enrichment ratio of 13 when using the combination of gravity separation and froth flotation at 90 g/t xanthate collector and 50 g/t glycol frother. The findings from this study show a significant potential for Te recovery from unconventional sources if appropriate physical beneficiation approaches are adopted.

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.

Zirconia Enrichment of Zircon from Arikya, Nasarawa State, Nigeria, by Magnetic and Gravity Separation Processes for Use as Reinforcing Agent in Composite Formulation

Acceptable zircon for composite formulation in the aerospace industry requires that the mineral contains a minimum of 65% zirconia (ZrO2). Despite having vast deposits of zircon, Nigeria’s aerospace industry has historically relied primarily on imported mild steel tubes for solid rocket motor cases (SRMCs) construction, resulting in three major challenges: low strength-to-weight ratio, pressure, and temperature containment. In this study, the Arikya zircon deposit located in northern Nigeria was investigated with the aim of upgrading low-grade zircon ore using magnetic and gravity separation processes for use in composite formulation for SRMCs. The dry high-intensity magnetic separator (DHIMS) produced a ZrO2 grade of 52.48%, recovery of 57.99%, and an enrichment ratio of 0.78 with a separation efficiency of 0.56, while the air-floating separator (AFS) generated the highest of 65.52% ZrO2 grade with 70.81% recovery and enrichment ratio of 1.25 with a separation efficiency of 0.25. The ZrO2 content increased from 40.77 to 65.52% after beneficiation. Iron oxide and titanium dioxide contaminants at 0.73 and 0.83% were reduced to 0.66 and 0.54%, respectively, while the specific gravity increased from 4.4 to 4.6 g/cm3. The ZrO2 content and specific gravity were improved to the minimum standard specified for zirconia-reinforced composite application and competed effectively with industrially/globally accepted zircon. These results demonstrated the efficacy of combining DHIMS and AFS to upgrade the low-grade zircon ore from Arikya, Nasarawa State.

Gravity Separation Tests of a Complex Rutile Ore

The complex rutile ore containing TiO2 and ZrO2 exhibited a high economical value. To effectively recover TiO2 and ZrO2 from the raw sample, a complete gravity separation process including a spiral chute and a shaking table was proposed. Chemical constituents, phase, liberation degree and size distribution were firstly characterized by XRF, chemical analyses, XRD, EPMA-EDS and screening to understand the mineralogy. Then, two stages of spiral chute separation tests were performed to treat the complex rutile ore. A rough zircon concentrate containing 33.18% ZrO2 was obtained after the first-stage spiral chute and a rough rutile concentrate containing 56.77% TiO2 was obtained after the second-stage spiral chute. To further improve the grade and recovery of ZrO2 and TiO2 in the rough products obtained by spiral chutes, shaking table tests were performed. A zircon concentrate containing 42.65% ZrO2 and a rutile concentrate containing 61.75% TiO2 were obtained. For the tailing of the first-stage spiral chute, a rutile product assaying 57.50% TiO2 was obtained, and the tailing was directly discarded as waste after the shaking table tests. Moreover, the distribution regularities of ZrO2 and TiO2 in the products were further revealed by XRD analyses. Finally, a closed-circuit beneficiation process was proposed to treat the complex rutile ore for achieving comprehensive and effective utilization.

Минералого-геохимические особенности золотосодержащих руд месторождения Пакрут (Центральный Таджикистан) как основа гравитационного обогащения

The mining sector, in particular gold mining, plays an important role in the economy of Tajikistan. Today, the issue of optimizing gold mining mechanisms, increasing its efficiency and expanding the resource base is of topical importance. The depletion of easily accessible gold deposits is stimulating the development of methods for extracting gold from refractory and low-grade ores. One of the promising methods of pre-treatment of such ores is gravity enrichment. The aim of the study is to characterize the Pakrut gold deposit, to determine its mineralogical and chemical composition, and to develop an optimal gravity enrichment scheme for gold recovery. Research objectives are as follows: to study the mineralogical composition and geochemical characteristics of gold-bearing ores, and then to develop a technique for their gravitational enrichment. The object of the study is the gold-bearing ores of the Pakrut deposit (Central Tajikistan). Materials and methods of research: analytical work and enrichment in laboratory conditions were carried out in the chemical laboratory of the Pakrut Joint Venture, the ore enrichment laboratory of the V. I. Nikitin Institute of Chemistry of NANT, the Central Committee of the Main Geological Directorate under the Government of the Republic of Tajikistan. It is found that gold in the Pakrut ores is mainly represented by native gold and electrum. The main gold-bearing minerals are pyrite, arsenopyrite, sphalerite, galena, jamesonite and some vein minerals. The gold content in the ore is about 6 g/t. The granulometric composition of gold is extremely uneven. Most of the gold particles are less than 10 μm in size and are coated with gold-bearing minerals, which hindered their release during grinding. In accordance with the characteristics of the gold deposit, gravity enrichment method has been used to extract the liberated coarse gold. Studies have shown that the gravity separation process is used for the primary processing of ore to recover coarse gold particles. The gold content and recovery in the gravity separation concentrates are 46.58 g/t and 44.59 %, respectively.

Applicability of the Teetered Bed Separator for Beneficiating Indian Iron Ore Fines: An Experimental Study

Higher alumina and lower iron content in Indian iron ore fines is a major problem for its effective utilization in the ironmaking process. India is the second largest steel producer in the world with an annual production of 200 million tons in the year 2020, whereas iron ore beneficiation of this country is highly derisory. Only 52 concentrators are required to produce 220 MTPA of iron ore. Most of the concentrator's benefits are limited to sizing and washing. In recent years, the Teetered Bed Separator (TBS) has gained significant importance and appeared as a viable option for beneficiating a variety of fine minerals. So, a systematic study has been carried out to verify the suitability of the TBS to reduce the alumina content and improve the iron grade in Indian iron ore fines. As the performance of gravity separation processes strongly depends on the feed particle size, a size-by-size beneficiation study was carried out to delineate the role of particle size on the performance of the TBS. Based on this study, the TBS is established to be a possible alternative to the other conventional equipment used for the beneficiation of iron ore fines.

Wet gravity separation and froth floatation techniques for rare earth elements beneficiation from monazite ore in Jordan

The demand for extracting Rare Earth Elements (REEs) from their deposits is growing significantly around the world since they are essential in many mature and growing industries. This study investigated the elemental and mineralogical composition of a Bulk sample and its potential for rare earth elements (REEs) beneficiation through Wet Gravity Separation (WGS) and Froth Floatation (FF) processes. Results obtained from WDXRF analysis showed that Si, Hf, Ti, Fe and Zr were the major elements present in the Bulk sample, with SiO2 accounting for 64.79 wt%. The TREOs concentration was around 0.90 wt%, dominated by Ce, La, and Nd, with other REEs present in smaller concentrations. XRD analysis indicated that Quartz was the major mineral present in the Bulk sample. WGS and FF were then used to beneficiate the oxides CeO2, La2O3, Nd2O3, Pr6O11, Y2O3, Gd2O3, and Sm2O3. Results showed significant concentration increases of these elements in the WGS concentrate, with high grade and good recoveries achieved for Ce, La, and Nd. Overall, the study provides insights into the potential of WGS and FF as a beneficiation technique for REEs in monazite ore.

Опыт освоения магнитно-гравитационной сепарации на предприятиях России и стран СНГ для повышения качества железорудного сырья

The paper analyzes the tasks of producing high-quality iron ore concentrates suitable for nonblast-furnace metallurgy and the challenges of processing magnetite ores with the current technological level of dressing equipment and technologies. One of the best methods to improve the quality and the grade of iron ore raw materials is the use of magnetic gravity separation in the technological process, which allows selective separation of the liberated magnetite particles from their aggregates in processing of undersize products of fine vibrating screening. This trend is implemented in the innovative magnetite ore processing technology that uses the principle of the staged output of finished concentrate. The technology makes it possible to produce a high-quality concentrate after the first grinding stage. The magnetic gravity separation has undergone industrial validation, has proven its efficiency in practice, and has become widespread at mining and processing plants not only in Russia, but also in the CIS countries. Over 180 MGS-2.0 magnetic gravity separators produced by Russian manufacturers have already been or are being implemented at various Russian and CIS companies. Industrial separators are equipped with modern automation systems providing high technological separation performance, have no rotating parts and are simple in design. The authors continue R&D works on creation of automated control systems for the magnetic gravity separation process based on designing digital models adapted for introduction into the plant’s automated process control systems.

Virtual Multiphase Flowmeter Using Deep Convolutional Neural Networks

Summary Petroleum wells produce a combination of oil, gas, and water in what is called a multiphase flow. This mixture is transported through flowlines to a tank separator that isolates and quantifies the volume of each fluid. However, this mechanical gravity separation process takes a long time, and the tank is often shared between many other wells in a field, making it difficult to allow an individual online measurement of the extracted fluids. Without this information, operators cannot effectively control production or estimate each well’s depletion rate, leading to losses or reduced profits. This paper aims to propose a low-cost, instantaneous model to perform this measure using artificial intelligence, commonly known as a virtual flowmeter (VFM). The idea behind it is to use data from pressure and temperature sensors already available on every well in addition to the state of the opening control valve to train a deep neural network with a convolutional layer to output each fluid’s volume rate. The proposed method is computationally simpler than recurrent neural networks and provides similar results. However, it still requires data to train the neural network. Adequate free databases of well production with telemetry are hard to find, so this paper proposes using the Schlumberger OLGA multiphase flow simulator software to provide the data, adjusting the simulator with fluid and operational information from actual wells. Tests have shown that the approximation with the proposed methods achieves up to 99.6% accuracy, making it possible to replace an expensive multiphase meter or use it as a redundant digital sensor for fault alerts of possible inaccurate readings.

Mineralogy of beach sand in Jumundo, Korea and recovery of heavy minerals using Humphreys spiral concentrator and shaking table followed by magnetic separation process

ABSTRACT The mineralogy of beach sand, which was sampled from an island, Jumundo of South Korea, was investigated and beneficiated using gravity and magnetic separation processes. Ilmenite was determined to be a major heavy mineral and, as minor heavy minerals, zircon, monazite, and sphene were observed. Quartz, biotite, microcline, kaolinite, hornblende, and chlorite were present as gangue minerals. The Ilmenite was concentrated with a Humphrey spiral concentrator and shaking table followed by magnetic separators (drum and cross belt types). As a final product, 18% of the Humphrey spiral system concentrate was recovered, and the grade of final product was determined to be 93% ilmenite. The electron probe microscope analysis indicates that ilmenite was a solid solution of major FeTiO3, minor MgTiO3 (geikielite), and MnTiO3 (pyrophanite).

Effect of Grain Crushing on the Hydraulic Conductivity of Tailings Sand

AbstractTailing dams are constructed to impound the byproducts of mining operations and are often built using the coarser fraction of the tailings resulting from gravity separation processes. The h...

Modes of motion of the medium and universal curves for gravity separation processes

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Medium Motion Modes and Universal Curves for Gravity Separation Processes

Medium Motion Modes and Universal Curves for Gravity Separation Processes

Extraction of Sc from Sc-Bearing V–Ti Magnetite Tailings

In this study, a magnetic separation–shaking table gravity separation process was used to treat Sc-bearing V–Ti magnetite tailings, and the Sc2O3 content in the Sc concentrate was enhanced from 0.0039 to 0.0061%. The majority of the Sc in the Sc concentrate originates from augite, hornblende, and aluminosilicate. Magnesium chloride and the Sc concentrate were placed in a roasting furnace for chloridizing roasting, causing the partial chlorination of Sc to ScCl3. Sc was extracted from the roasted ore using hydrochloric acid leaching. Sc extraction indices demonstrated 95.12% Sc2O3 leaching efficiency and 0.0011% Sc2O3 content in the acid leaching residue, clearly indicating the extraction of Sc. No noticeable peak of Sc was observed in the spectrum of the acid leaching residue. Most of the Sc in the roasted ores was dissolved as Sc3+, and it entered the liquid phase. The main minerals in the acid leaching residue were Mg2SiO4, CaTiO3, and Fe2SiO4.

Equal Extractability of Various Size Classes in Gravity Separation Processes

The theory of gravity classification processes is usually based on the regularities of the behavior of isolated particles in a flow. This approach has been justly criticized since long ago, since it is impossible to interpret the phenomena observed in actual processes (incomplete separation, affinity of curves, products contamination, etc.) from this standpoint. Only after providing an insight into the phenomenon of equal extractability of various size particles, have we managed to reveal the connection between the regularities of the behavior of an isolated particle and actual mass separation in a flow.

A study of gold ore for processability by gravity separation techniques

Today’s concentrators deal with a lot of gold deposits comprising smaller ore bodies, having low concentrations of the metal and situated in remote areas. The cost of detailed exploration and a full-fledged processability study considering the time and labour required may appear to exceed the cost of metal recovered from a deposit or a particular ore body. This paper describes some approaches to examining the gold ores mined at such deposits for processability and to developing gravity separation processes, which help save the time and cost of research without affecting the quality of resultant data. This research relied on the GRG test developed by Knelson in Canada, as well as a stage test developed by Institute TOMS in Russia (designed to determine optimum grinding size and number of processing stages). A simulation study was conducted to understand the recovery of gold during the grinding cycle (Stage 1) and to examine the Stage 2 process in a KC-CVD concentrator including concentrate refinement. The authors determined the distribution size of the feed material for each GRG test stage, documented the total percentage of gold recoverable by gravity separation as a function of the ore size, and established how the ore size and the KC-CVD concentrate output influence the gold recovery. This research study resulted in a process flow chart indicating the concentration performance based on gravity separation techniques.

Equal extractability of various size classes in gravity separation processes

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Kalman Filter-Based Convolutional Neural Network for Robust Tracking of Froth-Middling Interface in a Primary Separation Vessel in Presence of Occlusions

Bitumen in the oil sands industry is separated from sand using a water-based gravity separation process in a primary separation vessel (PSV). The interface between the froth and the middlings layer is an important parameter to control for optimal operation of the PSV unit. In this paper, a method using computer vision based on convolutional neural networks (CNNs) and Kalman filter (KF) is designed for the detection of the interface in PSV, with the CNN estimating both the interface level and the image quality. The proposed method consists of two parts: an offline and an online stage, wherein the parameters of CNN and KF are trained in the offline stage using the available data. The algorithm is made robust to any new type of occlusions, not present in the training dataset, in the online stage. Experimental results demonstrate that the proposed method is accurate and robust to different abnormalities in the process.

Cleaner Pre-concentration of Metals from Printed Circuit Board Waste Using Novel Dense Liquid Medium Based on Sodium Silicate

Printed circuit boards (PCBs) are present in most electrical and electronic equipment and contain valuable metals such as Cu, Au, Ag, and Pd, being considered attractive sources of metals. In order to recover those metals from PCBs by metallurgical processes, a pre-concentration step is needed. In this study, the metallic components from waste PCBs have been pre-concentrated using a separation process with dense liquid medium based on sodium silicate, as an alternative to toxic chloroform, which is commonly used. After grinding, the waste PCBs presented a mean particle size of less than 0.56 mm. After dense medium separation, similar concentrations of Cu and precious metals were obtained using either sodium silicate solution or chloroform. Therefore, sodium silicate has a high potential to be applied as a cleaner dense liquid medium in gravity separation processes.

A comparison of oil-water separation by gravity and electrolysis separation process

ABSTRACT This study investigates the performance of oil-water separation experimentally using two methods: gravity separation, and electrolysis separation. A factorial design experiment was conducted for gravity separation using a five-variable experimental plan where the factors are as follows: water flow rate, oil flow rate, temperature, number of compartments (2) and (1), and type of separator inlet deflector plate and elbow. The electrolysis separation was conducted using one factor at a time method. It was found that increasing temperature, voltage, and (NaCl) salt increases the performance of oil-water separation, however increasing the pH or volumetric oil to water ratio acts adversely.