Recovery Of Non-ferrous Metals Research Articles

Leaching of non-ferrous metals using a microemulsion in the system sodium dodecyl sulfate–butanol–caproic acid–kerosene–water

The possibility of using reverse microemulsion based on sodium dodecyl sulfate containing an extractant caproic acid for the selective recovery of non-ferrous metals and their separation from iron in the process of microemulsion leaching has been demonstrated. Using a model system with a mixture of oxides, the following recovery factors of metals are achieved in 5 h of leaching (%): Cu, 47.6; Mn, 12.8; Ni, 9.4; Co, 9.1; Fe, 4.3. When leaching from a sample of oxidized cobalt–copper concentrate, the recovery of metals is as follows (%): Cu, 60.0; Co, 51.3; Mn, 16.5; Fe, 10.0; Ni, 9.3.

Optimal design of a new Halbach array magnetic roller with axial eddy current force

Non-ferrous metal recovery is of great significance to the sustainable development of resources. Small-sized nonferrous metal particles account for a large proportion of nonferrous metals in solid waste, but the recovery efficiency is low. Eddy current separation is an important technology for physical recovery of non-ferrous metals. Optimizing its magnetic roller is extremely important for improving the recovery efficiency and economy of small-sized non-ferrous metals. In this study, COMSOL Multiphysics is used to establish a three-dimensional transient simulation model of the vertical rotary-drum ECS. On the basis of the two-dimensional Halbach array magnetic roll, the magnetic system of the magnetic roll is designed in the axial direction, so that the particles are subjected to the axial eddy current force opposite to the direction of gravity for the first time. This force can slow down the falling velocity of particles, increase the difference in falling trajectory and repulsion distance, improve recovery efficiency. In addition, due to the generation of axial eddy current force, the interlayer dislocation type magnetic roller can achieve the same recovery effect by only using 1/3 of the length of the basic type magnetic roller. Based on the electromagnetic theory and particle dynamics, by comparing the axial magnetic density distribution of different magnetic rollers, the axial eddy current force and the trajectory of non-ferrous metal particles, the generation mechanism of the axial eddy current force and the magnetic system structure that can generate the axial eddy current force are clarified.

Processing of Alluvial Deposit Sands with a High Content of Copper and Nickel Using Combined Enrichment Technology

The aim of the present research was to examine the process of bioleaching and the application of a combined process for the recovery of copper and nickel from industrial sand deposits. The investigated sample of sands finer than 0.1 mm in size contained 0.32% Ni and 0.22% Cu. Industrial sands were processed by bioleaching in flasks on a thermostatically controlled shaker. In addition, sand roasting experiments were carried out with ammonium sulfate. An attempt was also made to use a combined process, including low-temperature roasting of the sands mixed with ammonium sulfate, water-leaching of the roasted mixture, and subsequent biological after-leaching of the residue. In the process of roasting the industrial sands in a mixture including ammonium sulfate at a temperature of 400 °C, more than 70% of the non-ferrous metals were recovered. We examined the possibility of recovering non-ferrous metals using a combined process including low-temperature roasting of industrial sands and the additional recovery of non-ferrous metals by bioleaching using the Acidithiobacillus ferrivorans bacterial strain, which was found to increase the recovery of non-ferrous metals to up to 90%.

Recovery of non-ferrous metals from sulfide ores by bioleaching on the example of the Allarechensk technogenic deposit

The possibility of processing sulfide copper-nickel raw materials by heap bioleaching due to the environmental attractiveness of this approach is becoming an increasingly relevant topic for mining and processing. On the example of the Allarechensk technogenic deposit ore, the effectiveness of the bioleaching method for the copper and nickel recovery has been considered. The content of metals in the original ore sample: nickel – 2.42 % and copper – 0.75 %. The ore grinded to the size of –5+3 mm has been irrigated with a solution containing a strain of Acidithiobacillus ferrivorans. The S : L ratio is 4 : 1, the flow rate is equal to 0.1 mL/min. In pregnant solutions, the pH and redox potential values have been controlled, and the concentrations of ferrous and ferric iron, copper, and nickel ions have also been measured. The experiment duration is 11 months, 8.9 % nickel and 6.1 % copper have been recovered. Copper has been extracted from pregnant solutions by cementation on iron, the maximum recovery is 97.3 %. Thus, it has been shown that the proposed scheme for the recovery of metals is promising for the processing of sulfide raw materials, in particular, low-grade ores and enrichment waste.

Recovery of non-ferrous metals from sulfide ores by the method of heap bioleaching on the example of Allarechensk technogenic deposit

On the example of the Allarechensk technogenic deposit ore, the heap bioleaching method feasibility for the copper-nickel ores processing and non-ferrous metals recovery was considered. The content of metals in the initial ore sample was following: nickel – 2.42 %, copper – 0.75 %. The ore grinded to a size of -5+3 mm was irrigated with a solution containing a strain of Acidithiobacillus ferrivorans. The S:L ratio was 4:1, the flow rate was 0.1 mL/min. In pregnant solutions, the pH and ORP values were controlled, and the concentrations of ferrous and ferric iron, copper, and nickel ions were also measured. The experiment duration was 330 days, 8.9 % nickel and 6.1 % copper were recovered. The pathways for the metals extraction from pregnant solutions, as well as the utilization of bioleaching residue were considered.

Comparison of sphalerite concentrate leaching by chemical and microbially produced ferric sulfate

High-temperature ferric leaching is a promising method to improve the recovery of nonferrous metals from sulfide ores and concentrates. In this study, differences in the leaching kinetics of a sphalerite concentrate using chemical and biogenic ferric iron have been revealed. A comparison of leaching with a (i) biosolution containing ferric iron produced by microbial cells assigned to the strain Leptospirillum ferriphilum BUT, (ii) cell-free iron-containing L. ferriphilum culture liquid, and (iii) commercial reagent of ferric iron indicated that the latter allowed the maximum zinc and copper extraction into the solution. It is suggested that the products of the microbial cell lysis interacted with metal cations, decreasing their reactivity, and slowed down the removal of products from the reaction zone. This led to the formation of a dense layer of reaction products coating sulfide minerals. Probably, the rate of zinc and copper leaching was controlled by both the diffusion of the oxidant through a layer of the reaction products and a chemical reaction on the surface of mineral particles, indicating a mixed type of control. This pattern was independent of the chemical or biological origin of the ferric iron solution. The results provide new insights into the kinetic patterns and structural changes of sulfide minerals during ferric leaching and may contribute to the intensification of the processing of sulfide raw materials.

Recovery of Non-Ferrous Metals from PCBs Scrap by Liquation from Lead.

This article presents the results of research on the recycling of non-ferrous metals from PCB scrap using melting in metallic lead. The idea of this process is to dissolve (transfer) metals from PCB scrap in lead, and then liquation them by cooling the lead-metals alloy. PCB scrap was crushed and then melted into liquid lead. The lead after process was then poured into the casting mold and its chemical composition was examined. Among the various metals in the PCB scrap, copper and tin in particular are dissolved in lead. The more scrap dissolved in lead, the higher the concentration of copper and tin in the alloy. The highest obtained concentration of copper in lead were about 2.2 wt.%, and for tin about 0.8 wt.%.

The changing dynamics of the gas-dust flow in the flash smelter due to addition of a spoiler. Part 2. Pilot tests

The use of man-made deposits and fine ore concentrates in the flash smelter process, as well as the poorer quality of the raw materials observed (due to a higher share of particles smaller than 10 μm) lead to a higher amount of entrained dust and causes accretion in the slag end, uptake shaft and waste heat boiler. A higher dust entrainment is associated with a higher recycle, lower energy capacity of the raw materials and poorer recovery of non-ferrous metals. Numeric modelling of the heat and mass exchange processes in the gas environment of the settler and uptake shaft helped determine how different sizes and locations of the spoiler can change the gas flow parameters of the flash smelter. The modelling study showed that a 500 mm wide (the width of the settler) and 270 mm high spoiler mounted on the fire side of the settler at least 2,000 mm away from the entry to the uptake shaft could help reduce the amount of entrained dust by as much as 20% (relative) depending on the size and density of gas-dust particles. On the basis of the above calculations, a series of pilot tests was conducted on Line 1 of Nadezhda Metallurgical Plant in July 2019. Using various analysis techniques (such as thermal imaging of the surface in the spoiler area, the gas temperature, the gas flow rate, as well as methods used in analytical chemistry, scanning electron microscopy and X-ray spectral microanalysis), the authors of this paper examined the effect produced by the mounted spoiler on the gas flow. The authors would like to thank the leadership and the operations personnel of Nadezhda Metallurgical Plant for their support and great contribution to the pilot tests performed.

Instrumental monitoring of ore stockpile stability in heap leaching area

The current trend in open pit mineral mining is the increased recovery of nonferrous metals by heap leaching of oxidized ore on the shallow horizons. This article presents the case-study of Aktogai open pit copper mine having the project depth to 500 m. To implement heap leaching, ore stockpiling is carried out on ground surface, on a weak clayey and slightly sloped bottom, by layers 12–15 m high. The proposed instrumental monitoring procedure for the stockpiles in the heap leaching area uses a pillar of improved design, arranged below the depth of freezing and outside the potential displacement zone for the installation of an electronic tacheometer and check points with optical reflectors, stiffly bound with the ore stockpile using concrete. The high-precision geodetic measurements allow surveying in a single vertical plane using the check points arranged in the profile cross-section in the area of heap leaching. The values of displacements are determined both in vertical and horizontal planes of the ore stockpile. It is found that the stockpile body undergoes continuous compaction due to the permanent addition of new layers. The deformation mechanism of the stockpile is governed by the continuous stress, which is proved by the displacement values of the check points. In the middle of the stockpile, continuous compaction takes place at a rate up to 7.07 mm/day, while at the slope bottom of the stockpile, slight horizontal displacements toward the support pillar are observed at a rate to 4.90 mm/day. According to the current guidance procedures, such rates of displacement are not hazardous for the production process, as the threshold is 10 mm/day, but continuous instrumental monitoring of the ore stockpile stability in the heap leaching areas is required to reveal maximum allowable displacements and prevent landsliding.

Life cycle GHG emissions of MSW landfilling versus Incineration: Expected outcomes based on US landfill gas collection regulations

From a GHG perspective, most LCA studies find incineration (MSWI) to be preferred over landfilling because of high energy recovery offsets. In some studies, however, landfilling results in less greenhouse gases (GHG) emissions than MSWI. We investigated using LCA, the landfill gas (LFG) collection efficiencies and waste composition that led to landfills resulting in less GHG emissions. Then, we explored what theoretical minimum lifetime gas collection efficiencies can be expected when following US LFG regulations. Only landfills with high LFG collection efficiencies (at least 81%) and recovery of methane for energy resulted in less GHG emissions compared to the management of the same waste stream in MSWI; required efficiency increased to 93% without LFG energy recovery. Expected theoretical lifetime LFG collection efficiencies were modeled in the range of 30–80%, with the lower rates associated with landfills having smaller input masses, high decay rates, and low concentrations of nonmethane organic compounds (CNMOC). Our modeling found that only under a limited combination of conditions (e.g., high CNMOC, high waste input rate, low decay rate) could a landfill expect to achieve a LFG collection efficiency as high as 80%, and that this value falls just under the 81–93% collection efficiency threshold needed for a landfill to result in less GHG emissions than MSWI. When exploring the influence of higher oxidation rates, changing decay rates, varying electricity grids, and inclusion of nonferrous metals recovery offsets the collection effciency range needed increased in nearly all cases; the electricity grid and nonferrous metals offsets had the greatest influence.

The changing dynamics of the gas-dust flow in the flash smelter at Nadezhda metallurgical plant due to addition of a shield. Part 1. Model calculations

A poorer quality of the raw materials that go in the flash smelter operated by Nadezhda Metallurgical Plant, as well as the use of man-made deposits and fine ore concentrates with high concentrations of particles smaller than 10 μm, leads to a higher amount of entrained dust. Dust entrained by the gas flow leads to the formation of accretion in the slag end, uptake shaft and waste heat boiler. A higher dust entrainment is associated with higher loads on the gas duct, higher material turnover, decreased performance and recovery of non-ferrous metals. Fitting the furnace crown with a shield avoiding any major changes to the furnace design or the smelting process helps change the dynamics of the gas flow and lower dust entrainment. This paper defines the optimum location and dimensions of such shield. Depending on the particle size and the density of the gas-dust flow, with the shield installed, the estimated reduction in the amount of dust getting in the dust treatment system may reach 20%. 

Simultaneous Recovery of Precious and Heavy Metal Ions from Waste Electrical and Electronic Equipment (WEEE) Using Polymer Films Containing Cyphos IL 101.

In this article, the application of a polymer film containing the ionic liquid Cyphos IL 101 for the simultaneous recovery of precious and heavy metal ions ((Ni(II), Zn(II), Co(II), Cu(II), Sn(II), Pb(II), Ag(I), Pd(II), and Au(III)) from waste electrical and electronic equipment (WEEE) is described. The experiments were performed for solutions containing metal ions released from computer e-waste due to leaching carried out with concentrated nitric(V) acid and aqua regia. It was found that the applied polymer film allows for the efficient recovery of precious metals (98.9% of gold, 79.3% of silver, and 63.6% of palladium). The recovery of non-ferrous metals (Co, Ni, Cu, Zn, Sn, and Pb) was less efficient (25–40%). Moreover, the results of the performed sorption/desorption processes show that the polymer film with Cyphos IL 101 can be successfully used after regeneration to recover metals ions several times.

Derivatives of Neopentanoic Acid Hydrazide as Reagents for Flotation Recovery of Non-Ferrous Metals

Derivatives of Neopentanoic Acid Hydrazide as Reagents for Flotation Recovery of Non-Ferrous Metals

Recycling: value of non-ferrous metals recovery from catalysts rises by 49%

Recycling: value of non-ferrous metals recovery from catalysts rises by 49%

Processing of metallurgical dusts in sulfate-nitrate solutions

The composition of fine dusts of copper smelting enterprises contains zinc, copper, lead, which are of practical interest for their subsequent use in metallurgical processing, and arsenic, which is the main impurity and requires purification. For the processing of polymetallic middling products, various physicochemical processes are used — pyrometallurgical, hydrometallurgical, electro-chemical, having both advantages and disadvantages. One of the promising ways to extract valuable components into a solution, followed by selective conversion to cognominal products, is the considered sulfur — nitric acid technology. The implementation of such a scheme allows not only to achieve a high degree of extraction of valuable components from dust, but also to obtain monocomponent products suitable for further processing with the production of pure metals. Under laboratory conditions, regularities in the recovery of non-ferrous metals from the consumption of nitric acid were determined. The main parameters of the processing of metallurgical dust according to the sulfuricnitric acid scheme were selected. Experiments on sulfur-nitric leaching were carried out at a sulfuric acid concentration of 100 g/dm3, temperature 80 оC, L:S = 1:3 ratio, duration 3 hours, consumption of nitric acid varied from 0 to 0.7 g/g. The proposed technology allows in one stage to obtain Zn – As – Cu solutions that are suitable for processing with receiving individual products. The scheme provides for the return of nitrate-containing solutions to the leaching of sulfide material, which significantly increases the utilization rate of nitric acid. The main operations of the technology are: neutral leaching, sulfuric acid leaching, nitrate leaching, arsenic precipitation, copper precipitation as sulfide with return of part of Cu – As cake for conditioning it by copper and removal of arsenic. On the basis of the conducted research, the optimal parameters for the processing of metallurgical dusts for the selective separation of copper, zinc, lead and arsenic were established.

A new approach for the numerical analysis of an eddy current separator to recover non-ferrous metals from wastes

ABSTRACT Finite element codes are now part of the tools commonly used in the design and analysis of industrial products. The aim of this paper is to demonstrate the usefulness of the COMSOL multi-physics software for modelling the eddy current separation process (ECS) dedicated to the recovery of non-ferrous metals (Cu, Al, Pb …) from domestic and industrial waste, a technique of undeniable economic and ecological interest. This is ensured by means of a variable intense magnetic field distribution that selectively acts on materials that have different magnetisation characteristics.

Recycling of gold from waste electronic components of devices

Tremendous generation of e-waste and its illegal recycling are causing immense threat to environment as well as the loss of precious metals. The present research reports a novel hybrid process for the total recovery of gold from small depopulated components of e-waste. Connectors and integrated circuits (ICs) liberated from printed circuit boards (PCBs) were pulverized and processed for gold leaching using 10 g/L sodium cyanide solution at 40 °C and mixing time 15 min, where more than 95% gold was found to be leached out in single stage. From the obtained leach liquor, gold metal was recovered by charcoal adsorption followed by heat treatment. The raffinate left after adsorption of gold was found to contain ~10 mg/L gold, which was also recovered using Amberlite IRA 400Cl at equilibrium pH 9.6 in 30 min maintaining aqueous/resin (A/R) ratio 25 mL/g. The raffinate solution was enriched to 882.41 mg/L and the solution was further processed to get metal/salt using cementation/ evaporation. Obtained leached residue is processed for non-ferrous metals recovery and finally disposed-off after treatment and TCLP test. The effluent left after leaching could be easily decomposed and treated in ETP using standard environmental procedure.

Monitoring of less-common residual elements in scrap feeds for EAF steelmaking

ABSTRACT The steel scrap quality is classified according to the amount of residual elements. However, there is a limited analysis of some of the less common residual elements such as antimony (Sb), tungsten (W), cobalt (Co), nickel (Ni) and molybdenum (Mo) mixed with steel scrap received by steel plants. This paper reports a historical analysis of these elements in the steel compositions from two steel plants, located in different regions, during 2011 to 2018, analysing around 21000 heats. The concentration of W and Sb dropped by 0.002%, due to the increasing recovery of non-ferrous metals from mixed scrap. It was found that the calibration and maintenance of the spectrometer used to analysis had a direct impact on the results. The presence of Sb, W and Co in the steel indicates contamination from other materials, since 80% of the use of these elements is in applications associated with non-ferrous materials. This is the first analysis of these elements in steel scrap reported the literature and the conclusion of the study is that more attention should be paid to monitor less common residuals elements, because analysis of these elements can provide information about the quality of the metal scrap.

Copper Smelter Dust Is a Promising Material for the Recovery of Nonferrous Metals by the Waelz Process

Dust of gas cleaning systems in the process of blister copper production is a waste of class 2 hazard. The accumulation of copper smelter dust may cause significant damage to the environment in the places of their storage. This dust contains considerable contents of zinc, lead, tin, and copper, which makes possible its use for recovery of these elements. However, there are a number of characteristics such as complex multicomponent composition and high content of halogens. The physicochemical properties of the copper smelter dusts of FL PPM AO Uralelectromed (Russia) and PO Balkhashtsvetmet (Kazakhstan) were studied using chemical, X-ray phase, and electron microscopy methods. In both dust samples, the presence of lead in the form of sulfate and sulfide, zinc in the form of orthostannate, ferrite, and sulfide, and copper in the form of chalcopyrite was identified. To obtain the intermediate products for the production of zinc, lead, tin, and copper, the industrial processing of the copper smelter dust can be most effectively carried out by the proposed process flowsheet with one pyrometallurgical treatment in a Waelz furnace with further leaching steps.

ОЦЕНКА ВОЗМОЖНОСТИ ДОИЗВЛЕЧЕНИЯ ЦВЕТНЫХ МЕТАЛЛОВ ИЗ ЛЕЖАЛЫХ ХВОСТОВ ОБОГАЩЕНИЯ МЕДНО-НИКЕЛЕВЫХ РУД

ОЦЕНКА ВОЗМОЖНОСТИ ДОИЗВЛЕЧЕНИЯ ЦВЕТНЫХ МЕТАЛЛОВ ИЗ ЛЕЖАЛЫХ ХВОСТОВ ОБОГАЩЕНИЯ МЕДНО-НИКЕЛЕВЫХ РУД