Copper Ore Flotation Research Articles

Linking ores flotation results to the Kinsenda copper deposit mineralogical features: enhancing the recovery of copper retained in flotation tailings

ABSTRACT Since the Kinsenda concentrator commissioning in 2015, the selective flotation of mixed copper ores (67% as sulphides and 39% as oxides) from the Kinsenda deposit (DR Congo results in a recovery yield of 57% of copper as oxides versus 98% as sulphides.. Talings from the flotation of sulphide minerals contain 1.14% as total Cu including 0.38% as oxides. This research adopted a geometallurgical approach for enhancing the recovery of not floated copper. Consequently, it thoroughly studied the Kinsenda copper deposit mineralogy to explain causes of poor results of the industrial flotation of copper and conducted chemical and granulochemical analyses of tailings to describe and comprehend the copper behaviour during flotation. The effects from particles size in tailings, and the reagents’ suite components and their dosages on the copper flotation efficiency were investigated. Flotation results were significantly improved when tailings contain 70% particles with size smaller than 106 μm were floated using a reagents suite including 3600 g per t NaHS (sulphidiser), 360 g per t SNPX (collector) and 360 g per t AM810 (promoter). Indeed, the concentrate's grade in total copper reached 23.75%, with a recovery yield of 91.07% and 15.41% in oxidised copper, with a recovery yield of 91.26%.

The role of microbubble dose in combined microflotation of fine particles

Flotation of small particles is one of the global challenges facing the mineral raw materials processing industry. Large amounts of non-ferrous and rare metals are lost in the flotation tailings in the form of mineral particles below 15 µm in size as a result of the low effectiveness of their capture by coarse bubbles generated in conventional flotation machines. The method of combined microflotation, developed in recent years, uses conventional coarse bubbles (CB) and microbubbles (MB) produced in the stand-alone generator of air-in-water microdispersion, which serves as the flotation carriers. Depending on the MB dose, the effect of their application may be positive or negative. The theoretical analysis of various mechanisms of particle transfer onto the surface of coarse bubbles and further into the froth layer allowed to obtain the formula for the optimal MB dose f=d<sub>d</sub>/2d<sub>p</sub>r<sub>p</sub>, where d<sub>d</sub> is MB size; d<sub>p</sub> and r<sub>p</sub> respectively are the size and the density of particles. Experiments performed on the copper ore flotation tailings at the Atalaya Mining (Spain) and Chaarat Kapan (Armenia) concentrators showed that, besides the optimal MB dose in the range of 1-3 ml/g, there is another optimal MB dose in the range of 10-20 ml/g, where the copper recovery increases by several percent compared to the reference test (f = 0). The deep minimum in copper recovery is observed in the area between the optimal MB doses, which is by several percent lower than the value in the reference test.

Prediction of X-ray fluorescence copper grade using regularized stochastic configuration networks

In copper ore flotation processes, accurate measurement and estimation of the copper grade of the final products are crucial for field operations and control. Due to the presence of multicollinearity and outliers in the measured data, the existing on-stream X-ray fluorescence grade analyzer is inaccurate. To address these issues, this study proposes a robust data modeling algorithm to improve the performance of copper grade prediction. Specifically, a regularized stochastic configuration network and a generalized M−estimation method are used to overcome the uncertainties in the processing data. The experimental results clearly demonstrate that the proposed model outperforms other modeling algorithms in terms of prediction accuracy and robustness.

Organosolv lignin particles as an ecological reagents in the Kupfershiefer copper ore flotation

Mineral separation relies heavily on the process of flotation. This study explored the feasibility of using organosolv lignin nanoparticles and microparticles (OLP) as a greener alternative to xanthates in the flotation process for mineral separation. Xanthates are widely used but pose environmental and health risks. The efficiency of OLP as collectors was compared to collectorless flotation, resulting in approximately 50% copper recovery, indicating that OLP may not be a suitable replacement for xanthates. Further tests were conducted using a mixture of xanthates and OLP (birch nano and spruce micro) with varying substitution levels (20%, 30%, and 40%). The results demonstrated that increasing the dosage of OLP led to a decrease in flotation efficiency for copper. TOC analysis of the products revealed that high dosages (160 g/t) of birch nano and spruce micro as sole collectors showed beneficiation and selective recovery against copper. While OLPs did not prove effective as collectors, the study highlights their potential as substitutes for maltodextrin in selective flotation of the final concentrate. Two out of four tested OLPs were recommended for pilot scale testing.

Prospects for improving copper ore flotation performance using a modified reagent

Prospects for improving copper ore flotation performance using a modified reagent

Improving the performance of a low-grade porphyry copper ore flotation plant using a simulator that can predict grade vs. recovery curves

A large porphyry copper flotation plant has been simulated using a flotation model developed from first principles using the hydrophobic force as a kinetic parameter (Huang et al., 2022; Gupta et al., 2022). The input to the simulation was the size-by-class liberation matrix (mij) of a flotation feed, which was essential for predicting the size-by-class flotation rate constants (kij) and hence grade vs. recovery curves for the flotation bank. The model can be used to predict the performance of a flotation circuit provided that mij matrices are available for the feeds to the flotation banks in the circuit. With limited information on feed characteristics, we carried out a circuit simulation of the plant with some simplifying assumptions. The results suggest that significant financial benefits can be gained by recovering the slow-floating particles from the cleaner-scavenger tails that constitute the circulating load using an advanced separation technology in a separate copper recovery unit. With this approach, it is possible to substantially increase the throughput while maintaining copper recoveries and concentrate grades.

Technology for increasing the precious metals content in copper concentrate obtained by flotation

In the established technologies, the use of classic depressants of pyrite, such as lime represents one of the main problems in the flotation of gold-bearing copper (Cu) ores. Lime addition leads to the depression of the noble metals - gold (Au) and silver (Ag) that end up in tailings. Thus, the operator incurs economic losses. The current paper presents research aimed at replacing in flotation of copper pyrite ore, bearing gold and silver, the classical depressor lime with catholyte, i. e. with solution obtained during the electrolysis of water (pure or aqueous solutions) using a diaphragm electrolyser. Data from the conducted research show an increase in the content of precious metals in the obtained copper concentrate - from 148. 04 g/Mg Au and 112. 8 g/Mg Ag achieved by classical process to 216.45 g/Mg Au and 174.03 g/Mg Ag obtained by the proposed treatment. At the same time the Cu recovery increased by 3 % and the grade of Cu concentrate was 27.5 % Cu (compared to 16.2 % in the classical process). It seems that the main parameter influencing the selection separation process is the catholyte pH value.

Sustainable utilization of copper post-flotation waste in cement composites

The current way of managing the copper ore flotation waste is by placing it in waste neutralization facilities. However, flotation waste has great potential in application in cement composites. The article presents the detailed characteristics of post-flotation waste (PFW) and three types of cements: CEM I, CEM II/B-V, and CEM III/A, 42.5 MPa class. The post-flotation waste added for 20% of the cement mass increase the water demand to obtain the standard consistency. The highest pozzolanic activity was noted for mortars made of Ordinary Portland Cement and cured at 20 °C. The lower curing temperature, i.e. 10 °C, delays the hydration reaction, extends setting time, and reduces compressive strength. The conducted tests showed that the specimens produced from CEM I and PFW have the highest compressive strength (after 28 and 90 days), which means that PFW does not react with silica fly ash (from CEM II/B-V) and granulated blast furnace slag (from CEM III/A). The reaction of the waste with the components of the Portland clinker is preferred. The performed studies proved that the utilization of copper post-flotation waste allows for the development of sustainable and durable composite made of CEM I and indicated the possibilities of further testing of waste, in the direction of its use as a mineral additive for concrete.

Effect of wet ball milling on copper ore flotation by fractal geometry

ABSTRACT One of the important parameters in mineral processing is particles morphology, which is a function of the comminution mechanism. Particles morphology has considerable impacts in flotation process. Variations in particles morphology have been studied by different methods, including fractal geometry. This study aims to investigate the ball milling effect on particles flotation using fractal dimension, in which the calculations in the particles morphology has been made using the step-length method. The ore sample of under-investigation was a copper ore. The examined parameters include grinding time, ball load, and solid weight percentage. The collected fractal dimensions for particles ranged from 1 to 2, which is according to the principle of fractal geometry. Based on the results, low (30 minute) or high (50 minute) grinding time reduces fractal dimension and recovery because low grinding time is resulted in a coarse grain product while high grinding time is resulted in fine particles with spherical shapes. If balls load is high (8710 gr), predominant comminution force turns to an abrasive force are resulted in fine and spherical particles due to an increase in the accumulation volume. When the ball load decreased (4690 gr), the coarse particles were produced. Fractal dimensions and recovery are decreased in both cases. Low (40%) and high (60%) solid weight percentages are resulted in ineffective comminution, producing a coarse grain product. As a result, fractal dimensions and recovery are decreased. There is a direct correlation between recovery and fractal dimension.

Flotation of Copper Ores with High Cu/Zn Ratio: Effects of Pyrite on Cu/Zn Separation and an Efficient Method to Enhance Sphalerite Depression

Porphyry copper deposits are important sources of copper and typically processed by flotation to produce copper concentrates. As mining areas become deeper, the amounts of impurities, such as sphalerite, can be increased in copper ores, so the appropriate depression of sphalerite floatability should be achieved to obtain saleable copper concentrates. In this study, the flotation behaviors of chalcopyrite and sphalerite in model samples mimicking copper ores with high Cu/Zn ratios (i.e., the ratio of chalcopyrite/sphalerite = 13:1) were investigated with zinc sulfate as a depressant for sphalerite. In addition, the effect of pyrite—a major gangue mineral in copper ores—on the depression of sphalerite floatability with zinc sulfate was examined. When sphalerite and chalcopyrite coexisted, the floatability of the former was effectively depressed by zinc sulfate (Zn recovery: <12%), whereas the presence of pyrite promoted the release of Cu2+ due to the galvanic interaction with chalcopyrite, which resulted in the elimination of the effectiveness of zinc sulfate in depressing sphalerite floatability (Zn recovery: >90%). Despite the presence of much higher amounts of chalcopyrite and pyrite than sphalerite, the application of nitrogen (N2) gas limiting the galvanic interaction between pyrite and chalcopyrite by reducing the dissolved oxygen (DO) concentration in the system effectively depressed the floatability of sphalerite (Zn recovery: <30%).

Effect of sodium metabisulfite and slaked lime on the floatability and surface properties of chalcopyrite

In the flotation of complex copper ores containing chalcopyrite in seawater, sodium metabisulfite (SMBS) has been widely used as a pyrite depressant. Here, calcium ions in seawater or in process water because of pH control using lime (CaO) or slaked lime (Ca(OH) 2 ) can affect the floatability of chalcopyrite. However, the effect of SMBS on the floatability of chalcopyrite in the presence of calcium ions is unknown. Therefore, the current study investigated the flotation behavior and surface properties of chalcopyrite after treatment with SMBS in the absence and presence of Ca(OH) 2 . The flotation experiments demonstrated that both SMBS treatment and the addition of Ca(OH) 2 exhibited a depressing effect on the natural floatability of chalcopyrite. This depressing effect of SMBS and Ca(OH) 2 on the floatability of chalcopyrite was significantly decreased in the presence of potassium amyl xanthate (PAX). However, the combination of SMBS treatment and Ca(OH) 2 formed calcium sulfite (CaSO 3 ) on the surface of chalcopyrite, which significantly reduced the recovery of chalcopyrite from 97% to 66% when in the presence of PAX and at a pH of 9. • The effect of Na 2 S 2 O 5 (SMBS) and Ca(OH) 2 on the floatability of chalcopyrite was studied. • Both SMBS and Ca(OH) 2 exhibited a depressing effect on the recovery of chalcopyrite. • SMBS produced sulfate and hydrophilic species on the surface of chalcopyrite. • SMBS and Ca(OH) 2 form CaSO 3 precipitate that reduced the recovery of chalcopyrite. • SMBS reduced the adsorbed PAX on the surface of chalcopyrite.

Hybrid Serving of DOE and RNN-Based Methods to Optimize and Simulate a Copper Flotation Circuit

Prediction of metallurgical responses during the flotation process is extremely vital to increase the process efficiency using a proper modeling approach. In this study, two new variants of the recurrent neural network (RNN) method were used to predict the copper ore flotation indices, i.e., grade and recovery within different operating conditions. The model input parameters including pulp pH and solid content as well as frother and collector dosages were first analysed and then optimized using a two-step factorial approach. The statistical analysis showed a reliable correlation between operating parameters and copper grade and recovery with coefficients of 99.86% and 94.50%, respectively. The main effect plots indicated that pulp pH and solid content positively affect copper grade while increasing the frother and collector dosages negatively influenced the quality of the final concentrate. Despite the same effect from pulp pH, reverse effects from other variables were observed for copper recovery. Process optimization revealed that maximum copper recovery of 44.39% with a grade of 11.48% could be achieved under the optimal condition as pulp pH of 10, solid content of 20%, and frother and collector concentrations of 25 g/t and 9.9 g/t, respectively. Then, the predictive efficiency of long short-term memory (LSTM) and gated recurrent unit (GRU) networks with proper structure were evaluated using mean square error (MSE), root mean square error (RMSE), mean absolute percentage error (MAPE), and correlation coefficient (R2). The simulation results showed that the LSTM network with higher R2 of 0.963 and 0.934 for copper grade and recovery, respectively, was more effective than the GRU algorithm with the corresponding values of 0.956 and 0.919, respectively. The results show that the LSTM model could be useful in predicting the copper flotation behaviour in response to changes in the operating parameters.

Application of macromolecular organic polymer S-7261A in arsenic removal by flotation of refractory mixed copper ore

• S-7261A exhibits powerful depression on arsenopyrite . • S-7261A can replace Na 2 SO 3 in the separation of Cu-S-As bulk flotation . • The Cu recovery increased by 9.73% due to S-7261A selective depression. An organic compound S-7261A exhibiting satisfactory selectivity and powerful depression on arsenopyrite was introduced to replace sodium sulfite (Na 2 SO 3 ) in the separation of Cu-S-As bulk concentrate in Yunnan Datun Mill. The results of batch flotation tests indicated its excellent selective depressing power on both pyrite and arsenopyrite in the flotation separation of Cu-S-As bulk concentrate. The comparison tests of the pilot showed an evident improvement in the flotation index of copper and arsenic. With S-7261A replacing Na 2 SO 3 , Cu recovery was increased by 9.73%, As content being reduced to 1.02% in copper concentrate.

Effects of Pyrite Texture on Flotation Performance of Copper Sulfide Ores

Pyrite particles, having framboidal/altered texture, are known to significantly affect pulp chemistry and adversely affect flotation performance. Therefore, the main objectives of this study were to demonstrate influence of pyrite mineralogy on the flotation of copper (sulphidic) ores and develop alternative conditions to improve the performance. Two copper ore samples (Ore A and Ore B) having different textural/modal mineralogy and flotation characteristics were taken from different zones of the same ore deposit. Ore B contained framboidal pyrite and altered pyrite/marcasite, which is considered the main reason for the low flotation performance in both copper and pyrite flotation sections of the process plant. Flotation tests were conducted under different conditions using the two ore samples and a 50:50 blend. The results showed that Ore A could be concentrated under the base conditions, as applied in the existing flotation plant. On the other hand, Ore B did not respond to the base conditions and a copper recovery of only 5% could be obtained. Besides, blending Ore B with Ore A negatively affected the flotation behavior of Ore A. An alternative flotation chemistry was applied on Ore B using Na2S for surface cleaning and Na-Metabisulfite (MBS) for pyrite depression in the copper flotation stage. The surface cleaning reduced the rate of oxidation of the framboidal pyrite in Ore B. As a result, the copper recovery could be increased to 52% Cu for Ore B, and 65% for the mixed ore sample.

Digital technology for optimizing the sodium sulphide dosage during copper ore flotation

The article analyzes an advanced methodological approach to optimizing reagent flotation regimes during dressability studies for mineral raw materials. This paper studies the electrochemical processes occurring directly in the flotation slurry. In the course of laboratory experiments, the multifunctional effect of sodium sulfide during the flotation of off-balance ore of the Zhezkazgan ore field was studied. The use of the initial multifactorial matrices enabled the subsequent application of digital technologies, which, in turn, made it possible to improve the process indicators for the raw materials studied. It has been shown that the information space required for the implementation of digital technologies may be formed through the application of advanced ionometry methods. With the use of neural network modeling to monitor the electrochemical parameters of the slurry during flotation of copper ore of the Zhezkazgan ore field, it has been found that optimized sodium sulfide supply plays a decisive role in achieving high copper recovery, provided that the potential of the argentite electrode has been stabilized at the level of –450 mV when preparing the slurry before the flotation. The high reliability of the neural network model confirms the effectiveness of the original multifactorial matrices for use in laboratory tests. Due to the high accuracy of the resulting model, the optimal operating process parameters may be found.

Flotation classification in closed-circuit grinding as a way of reducing sulphide ore overgrinding

Research object and aim. Flotation classification in closed-circuit grinding is a way of improving copper ore flotation indicators by reducing minerals overgrinding. Due to valuable components froth recovery with their uncovering in the process of grinding, loss of copper in flotation tailings with secondary slime are reduced significantly. The research aims to study the possibility to improve the flotation of copper ore based on the use of flotation classification in the closed-circuit grinding. Methodology. In order to solve the problem, laboratory studies on closed-circuit grinding experimental modeling were carried out in a mode with and without flotation classification of hydraulic classification discharge. In each grinding mode, five stages of closed-cycle simulation have been implemented. Flotation classification was carried out in froth flotation modes with froth treatment with and without the tapered chute. According to experimental results, the loss of copper has been determined with slime in hydraulic classification discharge and flotation classification, and flotation classification end-product balance was calculated when operating in the closed-circuit grinding. Summary. The obtained experimental data prove the possibility of improving copper ore flotation by reducing minerals overgrinding in the course of flotation classification in closed-circuit grinding. The technology of flotation classification with froth treatment in tapered chutes make it possible to obtain prime concentrate with 18% copper mass fraction when extracting 37.7% copper into it, and final tailings in flotation classification discharge with 0.13% copper mass fraction under 2% loss.

Selectively Depress Copper-Activated Pyrite in Copper Flotation at Slightly Alkaline pH

Pyrite depression in the flotation of copper ores is difficult due to the activation of Cu2+ ions on pyrite surface. In this study, the radical chain reaction involving the redox cycling of Cu(I/II) induced by sodium metabisulphite (MBS) was exploited to selectively depress the flotation of copper-activated pyrite at pH 8.0. Electrochemical measurements revealed that the presence of Cu2+ and O2 was essential to the formation of $$ {\mathrm{SO}}_5^{\bullet -} $$ through sulphite oxidation, the main entity to convert the activating species Cu(I)S on pyrite to Cu(II)-hydroxide/sulphate, causing deactivation of pyrite. The depression role of MBS on pyrite flotation was closely associated with the type of grinding media which affected the electrochemical conditions of flotation. When forged steel was used as the grinding media, a high dosage of MBS was required to depress pyrite, but a low dosage of MBS could almost completely depressed pyrite when high chrome steel grinding media was used. This is because high chrome steel produced a stronger oxidation condition with a higher amount of Cu2+ and O2 which promoted the formation of $$ {\mathrm{SO}}_5^{\bullet -} $$ .

Potentially Exploitable Reprocessing Routes for Recovering Copper and Cobalt Retained in Flotation Tailings

This research aimed at recovering metals retained in the tailings from the flotation of copper (Cu) and cobalt (Co) ores conducted at the New Concentrator in Kipushi (NCK). Metals retention in the tailings (0.73% Cu and 0.37% Co) increased due to the removal of the gravity separation section from the processing circuit together with changes arising in the feed mineralogical characteristics namely the increase in sulfide minerals. The concentrator’s feed was traditionally composed of oxidized minerals of Cu and Co from the Luiswishi deposit (DR Congo). Experiments conducted at the laboratory scale enabled identifying two exploitable routes for recovering metals retained in the tailings: firstly, the sulfuric acid leaching of tailings under reducing conditions in view of preparing a leach liquor (2.43 g/L Cu and 1.10 g/L Co) that can be utilized for cementing Cu, using iron chips and precipitating Co; secondly, the flotation of valuable minerals using xanthates in view of obtaining a rougher concentrate grading 1.43% Cu and 0.75% Co recovered at 56% and 59%, respectively, and later on, the obtaining of a cleaner concentrate assaying 3.97% Cu and 2.4% Co at the recoveries of 35% and 43%, respectively. The final concentrate enables the hydrometallurgical extraction of Cu and Co.

Substantiation of the Erdenetiyn-Ovoo copper-molybdenum ore flotation technology with the use of tertiary acetylene alcohol

The article presents the results of a study of the factors affecting the efficiency of the copper-molybdenum ore flotation. The objective of this work was to substantiate and develop a reagent mode for flotation of the Erdenetiyn-Ovoo porphyry copper ores, which makes possible extracting main copper and molybdenum minerals into corresponding concentrates more fully and selectively. It is shown that the use of a DC-80 (2-methyl-3-butin-2-ol) flotation reagent in assosiation with the main base mode reagents — an AERO MX-5152 (a mixture of allyl ethers of xanthogenic acids with n-butyloxycarbonyl-O-n-butylthionocarbamate) combined nonionized collector, a BK-901B (a composition of dialkyldithiophosphate and O,N-dialkyldithiocarbamate) blending ionized collector; diesel fuel; a MIBC (methyl isobutyl carbinol) frother; sodium sulphide Na2S as a modifier and lime СаО as a pH regulator of the medium allows obtaining a noticeable, economically sound additional recovery of both copper and molybdenum. Quantum chemical calculations have permitted to establish an important feature of the mechanism of interaction between the DC-80 molecules that can form stronger complexes based on -bonds with metal cations of sulfide minerals in comparison with allyl ethers of xanthogenic acids. The energy indicators of the formation of bonds between Cu2S, the DC-80 molecules and allyl ether of xanthic acid were calculated. There were shown the models of the assumed interaction of small mineral particles with air bubbles during flotation, which are determined by physical and chemical properties of the molecules of acetylene-containing reagents. The principal difference between the properties of the foam bubbles formed by acetylene-containing molecules for at least 50% and that of the ordinary foam bubbles formed by standard frothers has been demonstrated in the view of the mechanism of their fixing on the surface of small particles of sulfide minerals and the surface of the bubbles. The optimal flotation mode, comprising a DC-80 reagent, BK-901B and AERO MX-5152 base collectors has been developed. The application of this mode will allow increasing the copper and molybdenum recovery into concentrates by 0.62% and 5.76%, respectively, reducing the flotation time by 35–40%, and improving the quality of resulting concentrates. Based on the research results, it is recommended to incorporate the DC-80 acetylene reagent into the basic flotation mode for conducting pilot tests at the Erdenet Mining Corporation enterprises (Mongolia).

Testing of the modified reagent during the dressing of oxidized copper ore in the enlarged laboratory conditions

In connection with the depletion of the ore base of the copper industry, there is a question of replenishing raw materials. In this regard, the involvement of oxidized copper ores in the processing is an urgent task. The paper presents the results of testing on an enlarged laboratory scale of the technology of flotation beneficiation of oxidized copper ore in the Balkhash region, based on preliminary sulfidization of the ore with a modified reagent. Research has been carried out to study the kinetics of the main, control and cleaning operations of oxidized copper ore flotation. Based on the data obtained, graphs of the dependence of copper extraction on the duration of operations were constructed. It has been established that preliminary sulfidization of ore with a modified reagent at its consumption of 20% of the stoichiometrically required amount makes it possible to obtain a commercial flotation copper concentrate with a content of 21% and recovery of 85% of copper.