Wash Water Rate Research Articles

Recovery of copper from printed circuit boards (PCBs) using shaking table

In recent years, there has been a growing focus on the reuse of metallic components from waste electrical and electronic equipment (WEEE) which refers to electrical and electronic equipment that has become obsolete, stopped working, or developed defects during production. In this research, shaking table was selected as a gravity concentration tool for the recovery of copper from the light components. The flowsheet included comminution, gravimetric concentration and physical/chemical characterization of feed material and products. The process parameters were deck angle (degrees), motion frequency (Hz), wash water rate (L/m) and particle size diameter. The Box Behnken Design (BBD) was used to optimize the performance of the wet shaking table and to identify the ideal combination of its operating parameters. By analysing the experimental design, it was found that the optimal settings for deck angle, motion frequency, wash water rate and particle size diameter were 2?, 50 Hz, 12 L/m, and ?500+300 mm, respectively. These optimal settings were located near the central points of the experimental design, suggesting that the actual optimal point could be within the designed space.

Separation behavior of Falcon concentrator for the recovery of ultrafine scheelite particles from the gold mine tailings

The utilization of mining and industrial wastes is gaining importance worldwide as it is a potential resource of many valuable minerals. The present study is focused on the separation of the fine and ultra-fine size scheelite particles present in the gold mine tailings using a Falcon advanced gravity concentrator. The manuscript reveals the mechanism of separation, segregation of particles, a saturation of the concentrate bed, and the role of different process parameters in the scheelite recovery. The experimental results indicate that the formation of the concentrate bed inside the Falcon bowl constitutes mainly coarse particles in the initial interval, which are later replaced by fine heavy particles. The saturation studies, carried out using different amounts of feed, indicate that the bowl can operate with 830g of feed sample, called the critical mass, beyond which erosion of particles occurs. Considering the Falcon concentrator efficiency is greatly influenced by operating variables such as bowl speed, wash water rate, and feed rates, statistical tools have been used to evaluate the influence of the different variables on yield, enrichment ratio, and recovery of WO3 values. The results indicate that only bowl speed and wash water have a significant effect on the separation efficiency. The optimum results for all the three responses were obtained as 17.16% yield, 4.66 as enrichment ratio, 67.5% of recovery at a rotational speed of 70 Hz, and wash water rate of 4 L/min where feed rate was fixed at 1 kg/min.

A Review on Froth Washing in Flotation

In the attempt to process lower-grade ores, mineral flotation has taken centre stage as the preferred recovery route. However, in many instances, the froth product does not have a high grade due to the entrainment of gangue minerals. Industry has solved this challenge by introducing froth washing mechanisms. Clean wash water is introduced into or on top of the froth to reduce the amount of entrained gangue in the final concentrate. This article reviews froth-washing systems in detail and highlights the advantages and disadvantages of each wash-water delivery mechanism. Comments on industrial uptake are provided. The indications are that froth washing improves the grade of the concentrate and influences froth stability and mobility. Other researchers have reported an improvement in recovery—especially of coarse particles—with wash water being added, while others have reported a reduction in recovery, especially with composite particles. Froth washing is generally applied in mechanical flotation cells by washing at the lip. In column flotation cells and Jameson cells, wash water is added to the entire froth surface. The literature also indicates that the wash-water rate, wash-water quality, type of wash-water delivery/ distribution mechanism and the area covered by wash water are critical parameters that dictate the efficacy of the washing system. Further research is necessary on the impact of wash-water quality on the froth phase sub-processes including froth rheology.

Wash water addition on protein foam for removal of soluble impurities in foam fractionation process

This work evaluates the addition of wash water to a foam fractionation cell in order to remove the soluble impurities from a protein foam. Due to the irreversible adsorption of the proteins at the air interface, the addition of wash water to the foam can displace the entrained substances downward together with the liquid, while the adsorbed proteins are not desorbed from the foam surface. Here, we performed experiments on bovine serum albumin (BSA), as a model protein and NaCl salt, as a model of soluble impurities. The experiments were conducted in a glass foam fractionation cell, where the liquid level was kept constant. The wash water was added on the foam top with different flow rates and BSA and NaCl concentrations were measured at the outlets for further analysis. The influence of initial bubble size and the wash water rate on purification efficiency were investigated. The results show that wash water displaces the entrained liquid in foam and reduces the salt content of the foam. The process shows higher salt removal for higher wash water rates as well as for foams with larger bubble sizes, where up to 93 % of the salt was removed from the main solution. A lower air flow rate can further enhance the washing efficiency. However, it intensifies the foam collapse and hence diminishes the foam outflow.

Recovery of clean coking coal from difficult-to-wash low volatile coking coal fines of Jharia coalfield by multi gravity separator

ABSTRACT Multi-gravity separator (MGS) is a centrifugal gravity separator deployed for beneficiation of fine particles with relatively low concentration. It is for the first time that a statistical tool was engaged to evaluate effects of the most influencing process variables and their actual impact upon the performance of MGS with respect to its potential to clean the difficult-to-wash low volatile coking (LVC) coal fines. Characteristics of LVC coal sample were analyzed and discussed in terms of physical properties, petrographic composition, washability, XRD and SEM analysis. Three different feed sizes such as – 500 μm, – 250 μm and – 150 μm were used for assessing the separation mechanism and efficacy of MGS along with three different process variables such as drum speed, shaking amplitude and wash water rate to study and ascertain the most efficient experimental design for obtaining optimal result. Results revealed that drum speed and feed size turned out to be most significant parameters for reduction of ash concentration. In design of experiments, clean coal ash, combustible recovery and separation efficiency were considered as response functions. Material balance for MGS unraveled that about 74% clean coal produced with 10% ash reduction from the feed ash of 32.8% could be achieved in single stage, in optimized process conditions.

An Investigation into Pre-concentration of Low-Grade Silica-Rich Malanjkhand Copper Ore by Wilfley Table

Pre-concentration stages are generally employed to process base and precious metals where the feed grades are inferior. The pre-concentration could remove major gangue minerals and enrich the desired metal content. Further, it improves the efficiency of subsequent concentration stages. In the present investigation, pre-concentration studies were carried out on the mixed copper ore from Malanjkhand, India, containing 0.48% Cu and 74.12% SiO2 contents. Mineralogical characterization revealed that chalcopyrite is the major copper contributing mineral along with a minor amount of malachite. The major gangue minerals present in the ore are quartz, feldspar and mica. Liberation studies of the feed material indicate that around 75% of gangue minerals (mainly quartz) are liberated at 150 µm. Pre-concentration studies were carried out using a Wilfley shaking table, wherein deck angle and wash water rate were varied to achieve the maximum recovery and grade. Optimum results were achieved at a wash water rate of 3.5 lpm and deck angle of 4.9°, wherein the silica rejection and separation efficiency of 52.19% and 53.68% were achieved. The final product assays 2.79% Cu grade and 66.32% copper recovery. The investigation results indicate that the shaking table could be used to pre-concentrate Malanjkhand copper ore.

Optimisation of a Multi-Gravity Separator with Novel Modifications for the Recovery of Ferberite

Tungsten is considered by the European Union as a critical raw material for future development due to its expected demand and scarcity of resource within Europe. It is therefore, critical to optimize European tungsten operations and maximise recoveries. The role of enhanced gravity/centrifugal concentrators in recovering tungsten from ultra-fine fractions should form an important part of this aim. Reported herein are the results of investigations to improve efficiency of Wolf Minerals’ Draklends mine, a major European tungsten mine, by recovering saleable material from a magnetic waste stream of a low-intensity magnetic separator using an enhanced gravity concentrator. The mine hosts wolframite and ferberite as the main tungsten bearing mineral species. A Mozley multi-gravity separator (MGS) C-900 was selected as it is suited to exploiting small variations in mineral density to affect a separation. Working with a current manufacturer, a novel scraping blade system was tested. To assess the MGS in a statistically valid manner, a response surface methodology was followed to determine optimal test conditions. The test programme showed that the most important parameters were drum speed and wash water rate. Under optimal conditions the model predicted that 40% of the tungsten could be recovered above the required grade of 43% WO3.

Optimization of Froth Feed Flotation in a Conventional Column for Beneficiation of Oxidized Coal

ABSTRACT Nowadays, the flotation of oxidized coal attracts more and more attention in China. In this study, a conventional flotation column with a novel of forth feed was used to beneficiate the oxidized coal. Exploratory experiments showed that the froth feed flotation can improve the overall combustible recovery by 22.25% with only 1.19% increase in ash content compared to conventional pulp feed flotation. Box-Behnken design (BBD), a response surface method, was used to design the flotation tests and model the effect of variables on responses. Four operating parameters, including frother concentration, superficial gas velocity, feed height and wash water rate as well as two response factors, namely ash content and combustible recovery were investigated. Meanwhile, their interactions were also described with three-dimensional response surface. Results showed that the models obtained for both ash content and combustible recovery were statistically significant. Additionally, the effect of wash water rate on ash content was found to be more significant than those of other parameters, while the combustible recovery depended more on the frother concentration. At last, the predicted optimal results were obtained within the experimental ranges, which well responded to the verification experiments.

Simultaneous Ash and Sulphur Removal from Bitumen Using Column Flotation Technique: Experiments, RSM Modeling and Optimization

An efficient method was employed for the ash and pyrite sulphur removal from bitumen using column flotation process. The bitumen samples containing 9.6% sulphur (6.81% in the pyrite sulphur form) and 26.4% ash were successfully showed up to 75.20% of pyrite sulphur (e.g.; 51.66% of total sulphur) and 70.81% of ash removal. The Box-Behnken Design (BBD) was employed to design the experiments, to optimize and evaluate the individual and interactive effects of six effective independent factors: the amounts of collector and frother agents, solid weight percentage in the pulp, particle size, wash water rate and feed rate. In order to investigate system a laboratory scale rig was built. In all experiments, pine oil and kerosene were considered as frother and collector agents, respectively. The best result for column flotation process were amount of collector (1.5 kg/tbitumen), amount of frother (0.3 ppm), pulp content (10% of solid), particle size (100 mesh), wash water rate (0.4 L/min), feed rate (1.5 L/min) and flotation time (10 min). The coefficient of determination, R2, showed that the RSM model can specify the variations with the accuracy of 0.924 and 0.938 for the percentage of ash and pyrite sulphur removal from bitumen, respectively.

Application of gravity separators for enrichment of South Chah-Palang tungsten ore

In the present study, the possibility of concentrating tungsten-copper vein ore in South Chah-Palang was examined using gravity separators including Jig Machine (-2360+600 μm), shaking table (-600+120 μm), and multi-gravity separator (MGS) (-120 μm). The representative sample contains 1.5% WO3 and 5.95% CuO. The main tungsten minerals were ferberite and wolframite and their appropriate liberation degree was approximately in the range of 250 μm. Box-Behenken and CCD response surface methods were applied to model and optimize jig machine and MGS results, respectively. Shaking table performance was modeled by full factorial design method. In Jig machine tests, the effects of water flow rate, frequency and feed particle size were investigated. Deck inclination, wash water, and feed water flow rate were operational parameters in shaking table. In the MGS testes, the effects of two parameters of tilt angle and wash water flow rate were inspected. In this set of experiments, WO3 recovery and grade were considered as responses of each model. The maximum recovery of WO3 in jig machine was obtained in water flow rate of 3.71 lit/min, frequency of 153rpm, and the particle size range of -2360+1700 μm. In this case, the grade and recovery of WO3 were 2.85% and 94.33%, respectively. The maximum WO3 recovery was 93.9% with grade of 8.20 % using shaking table in the deck inclination of 11 degree, feed water flow rate of 7 lit/min, and wash water flow rate of 8 lit/min. The maximum WO3 recovery in MGS attained with 3.45 degrees tilt angle and wash water rate of 3.16 lit/min. The grade and recovery of WO3 in the MGS method were 4.2% and 90.61%, respectively.

Optimization of Mineral Separator for Recovery of Total Heavy Minerals of Bay of Bengal using Central Composite Design

The present study is aimed at investigating the optimization of a mineral separator for processing of beach sand minerals of Bay of Bengal along Ganjam–Rushikulya coast. The central composite design matrix and response surface methodology were applied in designing the experiments to evaluate the interactive effects of the three most important operating variables, such as feed quantity, wash water rate and Shake amplitude of the deck. The predicted values were found to be in good agreement with the experimental values (R2 = 0.97 for grade and 0.98 for recovery). To understand the impact of each variable, three dimensional (3D) plots were also developed for the estimated responses.

Optimization of Operating Parameters of Oil Desalting in Southern Treatment Unit (HMD/Algeria)

Crude oil often contains fine saline water droplets, salt crystals, suspended solids and traces of metals. To meet business requirements, the salinity of the latter is limited to 40 mg/L and (BS&W) Basic Sediment and Water must to be lower than 1%. For this reason and to prevent corrosion, plugging, and fouling of equipment, electrical desalting plants are often installed in crude oil production units. This paper presents the results of a laboratory work conducted regarding the impact of important key parameters of oil desalting, namely: the rate of wash water, oil temperature, and injected chemical demulsifier amount in aim to achieve their optimum value and thus to reach the lowest oil salinity and (BS&W) without applying electrical field. Experiments conducted in South Crud Treatment Unit laboratory (UTBS/Hassi-Messaoud/Algeria), showed that the salts removal efficiency (SRE) increases with increasing the wash water rate, demulsifier amount and operating temperature. For 5% of wash water rate and 0.5% of demulsifier at 52°C, the (SRE) was 96.94%. Applying these parameters values to electrical desalting vessel with electrical field supply, would increase the (SRE) to a remarkable extent. The mean value recorded for (BS&W) during experiments was only 0.5%.

다중비중선별기를 이용한 광물찌꺼기로부터 비소제거 연구

광물찌꺼기에는 다양한 종류의 중금속이 함유되어 있어, 국내외에서 광물찌꺼기로부터 중금속을 제거하기 위해 많은 연구가 이루어졌으나, 중금속을 제거하기에는 여러 가지 문제점과 제약이 따르기 때문에 한계가 있었다. 따라서 이를 해결하고자 본 연구에서는 미립자의 선별까지도 가능한 다중비중선별기(Multi-gravity separator, MGS)를 사용하여 광물찌꺼기에 함유된 비소를 제거하기 위한 비중선별실험을 수행하였다. MGS를 이용하여 비중선별에 의해 비중이 높은 비소를 함유한 광물을 제거하고자 경사각, 세척수량, 광액농도, 드럼의 회전속도, 급광량에 따른 영향을 확인하였다. 실험결과 최적실험 조건인 MGS의 경사각 <TEX>$3^{\circ}$</TEX>, 세척수량 5 l/min., 광액농도 30%, 드럼 회전속도 208 rpm, 그리고 급광량 265.24 g/min. 에서 As 제거율과 산출율이 각각 88.21%와 92.25%인 결과를 얻었다. It comtained various kinds of heavy metal in beneficiatian tailing and in order to eliminate the heavy metals, various technologies have been researched, But there are a limits because many problems and restrictions are accompanied. Therefore, in this study, in order to solve this problem, It was performed gravity separation using melti-gravity seperator (MGS) to remove As contained in tailing, which can sort out even the fine particle. It was attempted a study to remove As, which is a kind of heavy metals, by MGS gravity separation and verified the impact by slope, wash water, pulp density, rotational speed and feed rate. In the results of performing gravity concentration under the condition with the MGS slope of <TEX>$3^{\circ}$</TEX>, wash water of 5 l/mm, pulp density of 30%, rotational speed of 208 rpm, and the feed rate of 265.24 g/mm, the As removal rate of 88.21% and yield of 92.25% were obtained.

Pilot-scale Studies of Ash and Sulfur Removal from Fine Coal by Using the Cylojet Flotation Cell

This article presents the results of pilot-scale studies of ash and sulfur removal from a Turkish coal by using the cyclojet flotation cell. The cyclojet cell, which was developed by H. Hacifazlioglu and I. Toroglu in 2006, utilizes an alternative jet flotation technique. Apart from being based on the working principle of jet flotation, the cyclojet cell incorporates centrifugal forces into the flotation process, thus providing an excellent separation for ash and pyritic sulfur removal. The most important parameters for the removal of ash and pyritic sulfur in the cycojet cell are the length of the conical jet, frother type, wash water rate, and froth thickness. With decreasing the conical jet length and increasing the wash water rate and froth thickness, there is an increase in the removal of pyritic sulfur. On the other hand, the frothing agents MIBC produced better results in terms of pyritic sulfur removal in the cyclojet cell. Under optimal conditions, the cyclojet cell removed 61.25% of the pyritic sulfur and 73.98% of the ash with a combustible recovery value of 71.10% without any need for a depressant.

OPTIMIZATION OF THE OPERATING PARAMETERS AFFECTING DAVIS TUBE MAGNETIC TESTER USING 2ND FACTORIAL DESIGN

The current practice of assessing the efficiency for recovery of magnetite by Davis tube tester at a magnetic induction is very important. 2nd factorial design is used for the parametric study of the magnetic separation because the classical approach is a tedious method. Factorial design is the most efficient way to explore the combinations of variables, because it uses every observation and calls only for as many observations as necessary. The results of the factorial experiments were used to identify the variables having a significant effect on magnetite recovery. The main objective of this work is to upgrade the iron ore using the Davis tube magnetic tester. It is also intended to study the most important operating parameters affecting the separation process. Among these are the feed size (µm), current intensity (Amp.), tube oscillation (rpm), tube inclination (degree) and wash water rate (Liter min-1). Consequently, the best fit relation can be expressed mathematically as: Y = 58.99 + 7.25X + 4.56I - 1.49O - 2.19W - 1.84S

Evaluation and Optimization of Operating Parameters Affecting the Davis Tube Magnetic Tester by Using 2ndFactorial Design

AbstractThe current practice of assessing the efficiency of recovery of magnetite is represented by Davis tube tests based on magnetic induction. 2ndfactorial design is used for the parametric study of the magnetic separation, because the classical approach is a tedious method. Factorial design is the most efficient way to explore the combinations of variables, because it considers every observation and uses only the most necessary observations. The results of the factorial experiments were used to identify the variables having a significant effect on magnetic recovery. The main objective of this work is to upgrade the iron ore using the Davis tube magnetic tester. It is also intended to study the most important operating parameters affecting the separation process. Among these are the feed size (μm), current intensity (A), tube oscillation (rpm), tube inclination (degree) and wash water rate (l/min). Consequently, the best fit relation can be expressed mathematically as: Y = 58.99 + 7.25X + 4.56I — 1.49O — 2.19W — 1.84S.

Analysis of Wet High-Intensity Magnetic Separation of Low-Grade Indian Iron Ore using Statistical Technique

The particle separation in a wet high-intensity magnetic separator depends on a number of variables. Applied magnetic field, particle size, and wash water rate play a vital role among them. Influences of these important variables were studied in detail following 33 full factorial designs of experiments using a laboratory/pilot-scale wet high-intensity magnetic separator (Gaustec G-340 Minimag). Statistical analysis of the results indicated that the influence of all these variables are significant (95% confidence level) on the recovery of magnetics and the order of significance follows, particle size > magnetic field > wash water rate. The experimental results used to develop the regression models to predict yield and grade at unknown operating conditions in the study range. Investigations carried out on a wet high-intensity magnetic separator using a low-grade iron ore sample containing 49.27% Fe shows that it is possible to upgrade to 62% Fe in the concentrate with poor yield values. A “tree” procedure (generally used to evaluate the flotation performance) was followed to evaluate maximum possible yield and grade by the magnetic separator. The “tree” procedure results provide useful information about the magnetic separation competence.

Processing of Alborz Markazi coal tailings using column flotation

Investigations were carried out on coal tailings by conventional cell and column flotation techniques. Tests were conducted to assess processing coal tailings of Alborz Markazi coal washing plant in Iran by column flotation. The effects of reagent type/dosage were investigated with conventional flotation and their results were used in the performance of column flotation. Also the effects of the air rate, the feeding rate, the wash water rate, the frother concentration, the collector dosage were evaluated with column flotation. These coal tailings have an average of 56% ash. This paper used factorial design to optimize grade and recovery of coal tailings. The column flotation results indicated concentrate produced under optimum conditions, kerosene, 2909 g/t; superficial air velocity, 0.96 cm/s; feeding rate, 3.6 lit/min; superficial wash water velocity, 0.98 lit/min; frother dosage, 350 g/t having an ash content of 12.11% and a combustible recovery of 28.51% was obtained.

Optimization of a Multi Gravity Separator to produce clean coal from Turkish lignite fine coal tailings

In this study, the beneficiation of two lignite tailings by Multi Gravity Separator (MGS) was investigated. The tailings samples from the Tunçbilek/Kütahya and Soma/Manisa regions have ash contents of 66.21% and 52.65%, respectively. Significant operational parameters of MGS such as solid ratio, drum speed, tilt angle, shaking amplitude, wash water rate, and feed rate were varied. Empirical equations for recovery and ash content were derived by a least squares method using Minitab 15. The equations, which are second-order response functions, were expressed as functions of the six operating parameters of MGS. The results showed that it is possible to produce a coal concentrate containing 22.83% ash with a recovery of 49.32% from Tunçbilek coal tailings, and a coal concentrate containing 22.89% ash with a recovery of 60.01% from Soma coal tailings.

The Benefication of Ultrafine Coal by Using the LM, Modified LM, and Conventional Flotation Cell

This article describes modification of the LM cell developed by Cheng Xinghua and using it to clean ultrafine coal. The major modifications involve replacing the column in a standard LM cell with a hydrocyclone and giving air into the system through a porous material. Thus, centrifugal forces are also incorporated into the system and a higher coal recovery is obtained. In addition, such important design and operating parameters as the apex diameter, gas flow rate, wash water rate, reagent dosage, and solid ratio were optimized, which affect the performance of the modified LM cell. Next, flotation experiments were carried out using the standard LM cell and conventional mechanical cell and the results were compared with those obtained from the flotation with the modified LM cell. It was established that the modified LM cell is an effective one for cleaning ultrafine coal and has a considerably high capacity. In fact, following the flotation of merely 60 sec, coals with an ash content of 46% yielded clean coals having a 10–15% ash content with 70–75% combustible recovery. The conventional flotation cell, on the other hand, produced a poor selectivity and lower coal yield. The separation efficiency of the modified LM cell was in the 55–60% range, whereas that of the conventional cell varied between 50–55%.