Enhancing XRF sensor-based sorting of porphyritic copper ore using particle swarm optimization-support vector machine(PSO-SVM)algorithm

X-ray fluorescence(XRF)sensor-based ore sorting enables efficient beneficiation of heterogeneous ores,while intraparticle heterogeneity can cause significant grade detection errors,leading to misclassifications and hindering widespread technology adoption.Accurate classification models are crucial to determine if actual grade exceeds the sorting threshold using localized XRF signals.Previous studies mainly used linear regression(LR)algorithms including simple linear regression(SLR),multivariable linear regression(MLR),and multivariable linear regression with interaction(MLRI)but often fell short attaining satisfactory results.This study employed the particle swarm optimization support vector machine(PSO-SVM)algorithm for sorting porphyritic copper ore pebble.Lab-scale results showed PSO-SVM out-performed LR and raw data(RD)models and the significant interaction effects among input features was observed.Despite poor input data quality,PSO-SVM demonstrated exceptional capabilities.Lab-scale sorting achieved 93.0%accuracy,0.24%grade increase,84.94%recovery rate,57.02%discard rate,and a remarkable 39.62 yuan/t net smelter return(NSR)increase compared to no sorting.These improvements were achieved by the PSO-SVM model with optimized input combinations and highest data quality(T=10,T is XRF testing times).The unsuitability of LR methods for XRF sensor-based sorting of investigated sample is illustrated.Input element selection and mineral association analysis elucidate element importance and influence mechanisms.

Effect of ultraviolet mutagenesis on heterotrophic strain mutation and bioleaching of low grade copper ore

The effect of ultraviolet mutagenesis on a heterotrophic strain(Providencia JAT-1) mutation was studied and bioleaching of low grade copper ore with mutant bacteria was investigated. The results show that the activity of bacteria was improved after ultraviolet mutagenesis; the best irradiation time was 120 s. Compared to the original bacteria, the cells density of mutant bacteria at stationary phase increased by 26% and ammonia produced by mutant bacteria increased by 12%. Higher activity of bacteria leads to a higher copper extraction rate. The bioleaching performance of Providencia JAT-1 was improved after UV mutagenesis. The copper extraction rate with mutant bacteria increased by 10.6% compared to the original bacteria. The ore surface was corroded and the fine particles were absent after bioleaching. Free copper oxide and copper silicates could be leached out easily by using JAT-1; a small part of the copper sulfide can also be leached out. Bioleaching using JAT-1 is more effective than ammonia leaching and copper extraction rate with mutant bacteria was 21.1% higher than that by ammonia leaching under the same condition.

Genetic Types and Metallogenic Model for the Polymetallic Copper–Gold Deposits in the Tongling Ore District, Anhui Province, Eastern China

The Tongling ore district is one of the most economically important ore areas in the Middle–Lower Yangtze River Metallogenic Belt, eastern China. It contains hundreds of polymetallic copper–gold deposits and occurrences. Those deposits are mainly clustered(from west to east) within the Tongguanshan, Shizishan, Xinqiao, Fenghuangshan, and Shatanjiao orefields. Until recently, the majority of these deposits were thought to be skarn-or porphyry–skarn-type deposits; however there have been recent discoveries of numerous vein-type Au, Ag, and Pb-Zn deposits that do not fall into either of these categories. This indicates that there is some uncertainty over this classification. Here, we present the results of several systematic geological studies of representative deposits in the Tongling ore district. From investigation of the ore-controlling structures, lithology of the host rock, mineral assemblages, and the characteristics of the mineralization and alteration within these deposits, three genetic types of deposits(skarn-, porphyry-, and vein-type deposits) have been identified. The spatial and temporal relationships between the orebodies and Yanshanian intrusions combined with the sources of the ore-forming fluids and metals, as well as the geodynamic setting of this ore district, indicate that all three deposit types are genetically related each other and constitute a magmatic–hydrothermal system. This study outlines a model that relates the polymetallic copper–gold porphyry-, skarn-, and vein-type deposits within the Tongling ore district. This model provides a theoretical basis to guide exploration for deep-seated and concealed porphyry-type Cu(–Mo, –Au) deposits as well as shallow vein-type Au, Ag, and Pb–Zn deposits in this area and elsewhere.

Mechanochemical sulfidization of a mixed oxide-sulphide copper ore by co-grinding with sulfur and its effect on the flotation efficiency

Mechanochemical sulfidization of a mixed sulfide/oxide copper ore by co-grinding with sulfur and additives including Mg(NO3)2 and Fe(NO3)3 salts and iron,aluminum and magnesium powders was investigated for the first time.Also,the influence of sulfidization during the wet-milling process was examined on the separation efficiency and recovery of copper in detail.The results demonstrated that co-grinding with sulfur solely had the best flotation performance at the value of 0.5 wt.%and it was attributed to the possible existence of S\\O bonding on copper oxides surfaces.In addition,adding magnesium nitrate salt,magnesium powder,iron nitrate salt and aluminum powder as additive associated with 0.5 wt%sulfur into ball milling caused the flotation improvement at the amounts of 0.2 wt%,0.2 wt%,0.5 wt%and 0.5 wt%,respectively.Also,the effect of grinding time and sulfidization pH with 0.5 wt%sulfur solely was determined and pH s of 7.5 to 8.5 gave the best results.The highest recovery(75.76%)and separation efficiency(63.44%)were achieved at pH of 7.5 and 8.5,respectively.

Effects of forced aeration on community dynamics of free and attached bacteria in copper sulphide ore bioleaching

Bacterial community dynamics and copper leaching with applied forced aeration were investigated during low-grade copper sulphide bioleaching to obtain better bioleaching efficiency.Results illustrated that appropriate aeration improved bacterial concentrations and leaching efficiencies.The highest bacterial concentration and Cu^(2+)concentration after 14-d leaching were 7.61×10^(7) cells·mL^(−1) and 704.9 mg·L^(−1),respectively,at aeration duration of 4 h·d^(−1).The attached bacteria played a significant role during bioleaching from 1 to 7 d.However,free bacteria dominated the bioleaching processes from 8 to 14 d.This phenomenon was mainly caused by the formation of passivation layer through Fe3+hydrolysis along with bioleaching,which inhibited the contact between the attached bacteria and ore.Meanwhile,16S rDNA analysis verified the effect of Acidithiobacillus ferrooxidans and Acidithiobacillus thiooxidans on the bioleaching process.The results demonstrate the importance of free and attached bacteria in bioleaching.

Acid equilibrium during bioleaching of alkaline low-grade sulfide copper ore

This article reports the study on acid equilibrium during bioleaching of alkaline low-grade copper sulfide ore. Adding auxiliary agents 1# （sulfur） and 2# （pyrite） makes bacterial leaching of copper and acid production carried out simultaneously because the auxiliary agents can be oxidized by bacteria and the oxidation products involve acid. The acid required for dissolving alkaline gangue during bacterial leaching is produced, and acid equilibrium is reached during the ore bio-leaching. The recovery of copper reaches more than 95%.

Study on the mechanical activation of malachite and the leaching of complex copper ore in the Luanshya mining area, Zambia

Mechanical activation(MA) of malachite was carried out by dry planetary grinding(DPG) and wet Isa grinding(WIG) methods. When the rotational speed was increased to 400 r/min in DPG, the specific surface area of malachite reached the maximum and the particle size reached the minimum of 0.7–100 μm. Agglomeration occurred between mineral particles when the rotational speed was increased to 580 r/min in DPG.However, no agglomeration was observed among particles with sizes 0.4–3 μm in WIG. X-ray diffraction analysis showed that, at a 580 r/min rotational speed in DPG, the amorphization degree of malachite was 53.12%, whereas that in WIG was 71.40%, indicating that MA led to amorphization and distortion of crystal structures. In addition, in the Fourier transform infrared(FT-IR) spectra of activated malachite, the bands associated with –OH, CO_3^(2-)and metal lattice vibrations of Cu–O and Cu–OH were weakened, and a new H–O–H bending mode and peaks of gaseous CO_2 appeared, indicating that MA decreased the band energy, enhanced dihydroxylation, and increased the chemical reactivity of the malachite.Furthermore, the leaching behavior of copper ore was greatly improved by MA.

Ore Genesis for Stratiform Ore Bodies of the Dongfengnanshan Copper Polymetallic Deposit in the Yanbian Area, NE China:Constraints from LA-ICP-MS in situ Trace Elements and Sulfide S–Pb Isotopes

The Dongfengnanshan Cu polymetallic deposit is one representative deposit of the Tianbaoshan ore district in the Yanbian area, northeast(NE) China. There occur two types of ore bodies in this deposit, the stratiform ore bodies and veintype ones, controlled by the Early Permian strata and the Late Hercynian diorite intrusion, respectively. Due to the ambiguous genetic type of the stratiform ore bodies, there has been controversy on the relationship between them and veintype ore bodies. To determine the genetic type of stratiform ore bodies, laser ablation inductively coupled plasma mass spectrometry(LA-ICP-MS) in situ trace elements and S–Pb isotope analysis have been carried on the sulfides in the stratiform ore bodies. Compared with that in skarn, Mississippi Valley-type(MVT), and epithermal deposits, sphalerite samples in the stratiform ore bodies of the Dongfengnanshan deposit are significantly enriched in Fe, Mn, and In, while depleted in Ga, Ge, and Cd, which is similar to the sphalerite in volcanic-associated massive sulfide(VMS) deposits. Co/Ni ratio of pyrrhotites in the stratiform ore bodies is similar to that in VMS-type deposits. The concentrations of Zn and Cd of chalcopyrites are similar to those of recrystallized VMS-type deposits. These characteristics also reflect the intermediate ore-forming temperature of the stratiform ore bodies in this deposit. Sulfur isotope compositions of sulfides are similar to those of VMS-type deposits, reflecting that sulfur originated from the Permian Miaoling Formation. Lead isotope compositions indicate mixed-source for lead. Moreover, the comparison of the Dongfengnanshan stratiform ore bodies with some VMStype deposits in China and abroad, on the trace elements and S–Pb isotope characteristics of the sulfides reveals that the stratiform ore bodies of the Dongfengnanshan deposit belong to the VMS-type, and have closely genetic relationship with the early Permian marine volcanic sedimentary rocks.

STUDY ON GREY FORECASTING MODEL OF COPPER EXTRACTION RATE WITH BIOLEACHING OF PRIMARY SULFIDE ORE

A model GM （grey model） （1,1） for forecasting the rate of copper extraction during the bioleaching of primary sulphide ore was established on the basis of the mathematical theory and the modeling process of grey system theory. It was used for forecasting the rate of copper extraction from the primary sulfide ore during a laboratory microbial column leaching experiment. The precision of the forecasted results were examined and modified via ＂posterior variance examination＂. The results show that the forecasted values coincide with the experimental values. GM （1,1） model has high forecast accuracy; and it is suitable for simulation control and prediction analysis of the original data series of the processes that have grey characteristics, such as mining, metallurgical and mineral processing, etc. The leaching rate of such copper sulphide ore is low. The grey forecasting result indicates that the rate of copper extraction is approximately 20% even after leaching for six months.

Diagenesis-Mineralization and Ore Prospecting of the Yangla Copper Deposit, Yunnan Province, Southwest China

The large-scale Yangla copper deposit, located in the central part of the Sanjiang Tethys polymetallic belt, is structurally controlled by the Jinsha River Fault and Yangla Fault. This deposit consists of seven ore blocks, including the Beiwu, Nilv, Jiangbian, Linong, Lunong, Tongjige and Jiaren. The Cu metal prospective reserves of the Yangla deposit are above 1 million tons. There are widely distributed Indosinian granodiorite and also many gabbro-diabase dikes and few quartz porphyries exposed in the Yangla ore district. The ore-hosting rocks are diopsode-garnet skarn, sericitie sandy slate and metamorphic quartz sandstone of the first member of the Devonian Linong Formation. Ore bodies occur as layered, stratoid, lenticular and veined shapes, and are strictly controlled by rocks, strata and structures.

Kinetics of chemical leaching of chalcopyrite from low grade copper ore: behavior of different size fractions

The kinetics of the chemical leaching of copper from low grade ore in ferric sulfate media was investigated using the constrained least square optimization technique. The experiments were carried out for different particle sizes in both the reactor and column at constant oxidation-reduction potential （Eh）, pH values, and temperature. The main copper mineral was chalcopyrite. About 40% of Cu recovery is obtained after 7 d of reactor leaching at 85℃ using -0.5 mm size fraction, while the same recovery is obtained at 75℃ after 24 d. Also, about 23% of Cu recovery is obtained after 60 d of column leaching for ＋4--8 mm size fraction whereas the Cu recovery is as low as about 15% for ＋8--12.7 and ＋12.7--25 mm size fractions. A 4-stage model for chalcopyrite dissolution was used to explain the observed dissolution behaviors. The results show that thick over-layers of sulphur components cause the parabolic behavior of chalcopyrite dissolution and the precipitation of Fe3＋ plays the main role in chalcopyrite passivation. In the case of coarse particles, transformation from one stage to another takes a longer time, thus only two stages including the initial reaction on fresh surfaces and S0 deposition are observed.

Enhanced copper recovery from low grade copper sulfide ores through bioleaching using residues produced by fermentation of agricultural wastes

Effects of residues produced by agricultural wastes fermentation(AWF)on low grade copper sulfide ores bioleaching,copper recovery,and microbial community were investigated.The results indicated that adding appropriate bulk of AWF made contributions to low grade copper sulfide ores bioleaching,which may be mainly realized through reducing the passivation layer formed by Fe3+hydrolysis.Improved copper recovery(78.35%)and bacteria concentration(9.56×10^(7)cells·mL^(−1))were yielded in the presence of 5 g·L^(−1)AWF.The result of 16S rDNA analysis demonstrated that microbial community was differentiated by adding AWF.Bacteria proportion,such as Acidithiobacillus ferrooxidans,Moraxella osloensis,and Lactobacillus acetotolerans changed distinctly.Great difference between samples was showed according to beta diversity index,and the maximum value reached 0.375.Acidithiobacillus ferrooxidans accounted for the highest proportion throughout the bioleaching process,and that of sample in the presence of 5 g·L^(−) AWF reached 28.63%.The results should show reference to application of agricultural wastes and low grade copper sulfide ores.

Bacterial leaching of discarded copper ores from Yongping, China

The elementary and phase analysis of discarded copper ores from Yongping of China has been performed. The experi- ments of extracting copper from the discarded copper ores were done with the mixed bacteria obtained through a series of enrichment, separation, domestication and combination tests. The results show that in the process of bioleaching, the pH value rises at first and drops gradually. The Eh value keeps rising along with the time and the appropriate Eh value varying between 750 and 800 mV will benefit the bioleaching copper. The high concentration of ferric ions is detrimental to the bioleaching copper. The results of bioleaching copper are good. That is, the copper recovery is 31.8% after 27 days.

The Mechanism of Structural Control of Ore Formation and Geochemical Characteristics in the Massive Sulfide Deposits of the Wushan Copper Ore Field,Jiangxi

The ore-controlling mechanism of the bedding fault system in the massive sulfide deposits of the Wushancopper orefield may be generalized as the control of ore deposition by optimum surface in an ore-formingstructural trap. The mechanism has three major features: (1) timing of mineralization; (2) positioning of hostformation; and (3) dependence of ore-controlling structure on properties of rocks. The 'optimum surface' is adivisional structural plane which marks obvious difference in physical, chemical and mechanical properties andis favorable for mineralization. It is also a unity of structures. lithofacies and orebodies. The structural and geochemical characteristics of the ore deposits indicate the migration trend of the ma-jor characteristic clements in the ore-controlling fault belt: elements with a small radius (Si, Fe, Mg and Al)moved towards and concentrated at the center of the belt while large-radius ones (Ca, K and Na) were remotefrom the center.

Ore Minerals and Genesis of Lala Copper Deposit,Sichuan Province

The Lala Cu deposit in Sichuan Province is one of the most important large deposits in SW China,both in terms of Cu and associated Au-Mo-Co-REE-Fe. Systematic ore petrology study shows that ore minerals are mainly composed of hydrothermal magnetite,chalcopyrite and molybdenite.The wall-rock alterations include biotitization,silicification, carbonatation,albitization,potash feldspathization, apatitation,actinolitation and fluoritation,et al. The Pyrite and magnetite have euhedral-subhedral crystalline grained texture and the chalcopyrite

Bioleaching of copper oxide ore by P seudomonas aeruginosa

Bioleaching is an environmentally friendly method for extraction of metal from ores. In this study, bioleaching of copper oxide ore by Pseudomonas aeruginosa was investigated. Pseudomonas aeruginosa is a heterotrophic bactermm that can produce various organic acids in an appropriate culture medium, and these acids can operate as leaching agents. The parameters, such as particle size, glucose percentage in the culture medium, bioleaching time, and solid/liquid ratio were optimized. Optimum bioleaching conditions were found as follows： particle size of 150-177 μm, glucose percentage of 6%, bioleaching time of 8 d, and solid/liquid ratio of 1：80. Under these conditions, 53% of copper was extracted.

SYNERGISTIC ACTIVATION OF CHELATING AGENT ON XANTHATE DURING THE FLOTATION OF REFRACTORY COPPER OXIDIZED ORES

For realizing the effective flotation of refractory copper ox-idized ores and developing the activation-flotation theory , the influences of nine different organic chelating agents on xanthate collection pcnver and its adsorption characteristics ivere studied in the flotation of malachite and chrysocolla representatively selected by means of XPS,IR, absorbed quanti-ty measurements and flotation tests.For easily-dissolved malachite flotation , a small amount of chelating agent can obviously enhance xanthate collecting power and make malachite floated easily , and so reduces the consumption of xanthate. For hard-dis-晄olved chrysocolla, chelating agent is able to increase its recovery to 90% , but the chelating agent consumption is high. Chelating agent and xanthate can produce synergistic adsorptions, which follmv Freundlich's adsorption equation on malachite and Chrysocolla surfaces. The high chemical activity of chelating agent and its synergistic activation on xanthate are the key to improving xanthate collection poiver. The synergistic activation of chelat-ing agent on xanthate on melachite surfaces is clearly stronger than on chrysocolla surfaces. According to experimental results, it can be thought that the synergistic activation results from the synergistic complexation of chelating agent and xanthate with copper ions to form biligand-tribasic co-ordination complex.

Effect of Desliming on Flotation Response of Kansanshi Mixed Copper Ore

The Kansanshi mixed copper sulfide-oxide ore contains significant proportions of fine material manifesting in a variety of processing challenges. This paper presents the work which was carried out to evaluate the efficacy of desliming in improving the flotation response of the ore. Two modes of desliming were investigated, namely;sieving and elutriation after which the deslimed material was subjected to Kansanshi standard laboratory flotation conditions. The minimum copper feed grade for the mixed copper ore was 0.5% Total Copper (TCu). The outcome of this work has shown that desliming improves the flotation response of the Kansanshi mixed copper ore. At a rougher copper concentrate grade of 8%, copper metal recoveries obtained with desliming were in excess of 70% compared to 58% achieved with baseline tests without desliming. It was further observed that desliming resulted in improved flotation rates for the sulfide minerals. For a flotation time of 3 minutes, recoveries of 69% and 74% were obtained with elutriation and sieving respectively compared to 58% recovery for baseline tests. From the same results it was also evident that, of the two modes of desliming investigated, sieving yielded better performance than elutriation.

A PRELIMINARY STUDY ON METALLOGENESIS OF THE LAMASU COPPER POLYMETALLIC ORE DEPOSIT, XINJIANG

The Lamasu copper polymetallic mineralized region lies in the south of Wenquan County, Xinjiang and in the Northwest lakeside of the Sailimu Lake. Seen from the geotectonic position, it belongs to North Tianshan geodome system, Tianshan diwa region, Central Asian crustobody. Copper and zinc polymetallic ore bodies had been formed in the skarn of the contact, between the metamophic carbonate rocks of the Kuximqiek Group, Jixian System and early mid Varisean acidic rockbodies. The formation of the ore deposit was the result of the successive activities of the crust and mantle and the tectonic and magmatic activities.

An Analysis of Contemporary Copper Recycling in China

Copper consumption increased very quickly in China in recent years,which could not be met by inland copper industry.In order to achieve a sustainable development of copper industry,an analysis of copper recycling in China was necessary.For the life cycle of copper products a copper-flow diagram with time factor was worked out and the contemporary copper recycling in China was analyzed,from which the following data were obtained.The average life cycle of copper products was 30 years.From 1998 to 2002,the use ratio of copper scraps in copper production,the use ratio of copper scraps in copper manufacture,the materials self-support ratio in copper production,and the materials self-support ratio in copper manufacture were 26.50%,15.49%,48.05% and 59.41%,respectively.The materials self-support ratios in copper production and manufacture declined year by year in recent years on the whole,and the latter dropped more quickly.The average index of copper ore and copper scrap from 1998 to 2002 were 0.8475 t/t and 0.0736 t/t,respectively;and copper resource efficiency was 1.1855 t/t.Some efforts should be paid to reduce copper ores consumption and promote copper scraps regeneration.Copper scraps were mostly imported from foreign countries because of shortage in recent years in China.Here the reasons related to copper scraps deficiency were also demonstrated.But we can forecast:when copper production was in a slow rise or in a steady state in China,the deficiency of copper scraps may be mitigated;when copper production was in a steady state for a very long time,copper scraps may become relatively abundant.According to the status of copper industry in China,the raw materials of copper production and manufacture have to depend on oversea markets heavily in recent years,and at the same time,the copper scraps using proportion and efficiency in copper industry should be improved.