Reagent Regime Research Articles

Enhanced recovery of low-grade copper ore and associated precious metals from iron tailings: A case study in China

In the processing of copper and precious metal recovery in a mine in Chengde, Hebei Province, the decrease in copper mineral content and finer grain size distribution of the selected ores have caused challenges in the existing milling process. This has led to difficulties in achieving significant dissociation of chalcopyrite, resulting in decreased separation efficiency of copper and associated precious metals. Particularly, there is a notable loss of precious metals in the flotation tailings. Using BPMA and other detection equipment, the occurrence state, distribution patterns, and liberation degree of copper and associated precious metals in iron tailings were investigated. Subsequent flotation experiments examined the impact of grinding regimes on mineral liberation and reagent regimes on mineral enrichment. Subsequently, flotation experiments were conducted to examine the influence of grinding regimes on mineral liberation and reagent regimes on mineral enrichment. The research findings revealed that copper and precious metal contents in iron tailings are extremely low and finely disseminated within gangue minerals, posing challenges for liberation. Under the optimal conditions determined from flotation experiments, a laboratory closed-circuit process consisting of one rougher, one scavenger, and two cleaner stages yielded a copper concentrate with a grade of 11.33 %, a recovery efficiency of 66.95 %, and containing 9.42 g/t gold, 52.72 g/t silver, 2.78 g/t platinum, and 8.46 g/t palladium. The SEM-EDS analysis further emphasizes the necessity to tailor grinding and flotation processes to optimize the liberation and subsequent recovery of these valuable minerals, avoiding excessive grinding of gangue minerals which could negatively impact flotation performance.

Effect of frother on dynamic detachment of rising bubble-coarse particle aggregates at gas-liquid interface

In the flotation process, the bubble-coarse particle aggregates easily undergo detachment at the gas-liquid interface, resulting in low mineral recovery. This paper tested the variation rule of surface tension with a concentration in the solution of four alcohols frother, namely, n-pentanol (NPA), methyl isobutyl carbinol (MIBC), 2-octanol, and polypropylene glycol (PPG). The effects of frothers on the motion characteristics of rising bubble-coarse particle aggregates and the dynamic detachment of aggregates at the gas-liquid interface were investigated separately using a high-speed dynamic camera system and a dynamic detachment device. The results showed that the solution surface tension decreased and then tended to be stabilized with the increase of frother concentration. Under the same concentration, the stronger the surface activity of the frother, the smaller the rising velocity of the bubble-coarse particle aggregates, and the more stable the motion state of the aggregates, with a smaller velocity fluctuation. The lower rising velocity reduced the particle detachment probability when aggregates collided with the gas-liquid interface. The merger time of the bubble-coarse particle aggregates was extended with the improved surface activity of the frother, increasing by more than 1 s compared to the solution without the frother. The study will contribute to effectively reduce the dynamic detachment probability of bubbles-coarse particle aggregates at the gas-liquid interface by selecting the type and concentration of frothers, meanwhile optimizing the reagent regime to enhance the coarse particle flotation recovery in the practical production process.

Technological evaluation of reagent regimes for flotation of gold-bearing antimony ore

Technological evaluation of reagent regimes for flotation of gold-bearing antimony ore

Технология переработки сухих отходов сорбции и растворов хлоридов сурьмы

Reducing the loss of valuable components during the processing of complex gold-antimony ores, increasing the extraction of antimony during the flotation of sulfide minerals, is an urgent scientific problem. The aim of the study is to maximize the extraction of gold and antimony from dry sorption waste after gold cyanidation, and to improve the reagent regime of the antimony mineral flotation process. Research objectives are as follows: evaluation of the technology efficiency for processing dry sorption waste; extraction of gold from the cake of acidic leaching of antimony; production of various antimony-containing products from solutions of antimony chlorides; study of the possibility of replacing lead with a mixture of zinc and copper cations to hydrophobize the surface of antimony sulfide minerals during flotation. The object of the research is man-made and natural mineral raw materials containing gold and antimony. The following research methodology and methods are used: information analysis, evaluation of existing scientific developments, methods of theoretical and experimental research. A new technological solution has been proposed: acidic (a mixture of hydrochloric acid and hydrogen hydroxide) hydrometallurgical technology for processing dry sorption waste in order to extract gold and antimony. Acid treatment makes it possible to completely transfer antimony into solution, significantly improves the quality of the cake for subsequent cyanidation and gold extraction, reduces the volume of material for processing by cyanidation, and simplifies cyanidation technology. Sb2S3 activation and the possibility of lead (Pb(NO3) replacement have been studied 2) a mixture of zinc and copper (ZnSO4 and CuSO4) during the flotation of antimony ores from the Khipkoshinsky deposit in the Transbaikal Region. This has made it possible to create favorable conditions for interaction with xanthogenate and hydrophobize the surface of sulfide minerals. Theoretically, hydrogen sulfide substitutes such as NaCNS, KCNS, CuCNS for use in the flotation process were evaluated.

Исследование реагентного режима флотации одного из золоторудных месторождений Восточного Забайкалья

The relevance of the problem is that the final product of flotation of the Eastern Transbaikalia deposit to be sold, has a low content. The object of the research is as follows: technological sample of the original ore of the gold deposit in Eastern Transbaikalia. The purpose of the research includes the search for the optimal reagent regime during the flotation process to improve technological performance. The research objectives are to study the chemical and mineral composition and to investigate the possibility of using reagents based on alcohols and C4-C8 esters “KETGOL”, “KETGOL improved”, “KON-92”. The research methodology is based on studying the properties of the components and their influence on the flotation process. The material composition of the ores has been studied by methods of atomic emission spectral quantitative analysis, X-ray fluorescence, phase atomic absorption analyzes and atomic emission analysis with inductively coupled plasma ICP-AES. The mass fraction of total and organic carbon is determined by the infrared absorption method. The gold content in the original ore is based on assay data. When conducting flotation experiments, the equipment of JSC Irgiredmet has been used. As a result of the research, the material composition is studied and laboratory studies of flotation enrichment of the ore sample are carried out. Conclusions on the material composition are as follows: the studied ore sample belongs to the primary gold-quartz, moderate sulfide mineral type of ore. The gold content is 3.12 g/t, silver – 6.9 g/t. The gold in the ore is mostly small and thin, its fineness is 708. The results of flotation enrichment have showed that the use of the KETGOL reagent as an additional collector to potassium butyl xanthate (BX) in a 2:1 ratio with a total consumption of 90 g/t is an effective means of increasing gold recovery to ~87–89 %, with In this case, the quality of the main flotation concentrate remains at the level of ~15.5–16.5 g/t.

Xanthates and Dithiocarbamates: Synthesis, Characterization and Application in Flotation Processes

Abstract: It is known that flotation is the main method of extracting non-ferrous metals. The need of modern society for precious metals is constantly growing, and deposits of easily reversible ores are being depleted. Therefore, the improvement of the reagent regime and the search for new flotation reagents is an urgent task. We analyzed the literature data on the synthesis and use of common collectors such as xanthates and dithiocarbamates. Particular importance is given to recent progress in the functionalization of xanthates and dithiocarbamates, their selective characteristics and flotation mechanisms. Progress in the field of flotation can be made in the use of new effective reagents and their combinations, as well as in the modification of already known collectors. The generalization of the material in this review will help in the development of this area. The mini-review summarizes the syntheses of collectors such as xanthates and dithiocarbamates with the increased selective properties in the flotation process of non-ferrous metals. Furthermore, this review provides an analysis of the developments in these studies, especially highlighting recent progress in the functionalization of xanthates and dithiocarbamates, their selective characteristics and flotation mechanisms.

Selectively separating scheelite from fluorite by using Nitrilotri(methylphosphonic acid) as an efficiency depressant to modify the surface properties of fluorite

Owing to the similar surface properties of scheelite and fluorite, the separation of them is very difficult by only using the traditional collectors of fatty acids. In this study, Nitrilotri(methylphosphonic acid) (ATMP) was used as a depressant to realize the efficient separation of these two minerals. The separation performance and the adsorption mechanism of ATMP on scheelite and fluorite were explored by the flotation experiments and surface analyses. Flotation results indicated that ATMP exhibited strong inhibition on the fluorite flotation but did not affect that of scheelite, and a satisfactory separation of scheelite from fluorite was achieved at the reagent regime of 60 mg/L ATMP, 40 mg/L sodium oleate (NaOL) and pH 10.0. Zeta potential measurements and AFM detections showed that the intense adsorption of ATMP onto fluorite was occurred and which could prevent the subsequent adsorption of NaOL on fluorite, while the adsorption of ATMP onto scheelite was weak and the further interaction between NaOL and scheelite was hardly influenced by it. Moreover, Fourier transform infrared (FTIR) spectroscopy and X-ray photoelectron spectroscopy (XPS) analyses confirmed that the interaction between calcium ions exposed on fluorite surface and the phosphate groups of ATMP accounted for the chemisorption of ATMP on fluorite. As a result, ATMP can be selected as a potential depressant for separating scheelite from fluorite.

Enhancement on the selective flotation separation of carbon coated LiFePO4 and graphite electrode materials

With the rapid development of lithium-ion batteries, the recycling of spent lithium-ion batteries will be a big challenge in the future, among which the recycling of spent positive and negative electrode materials powder is a difficult point. Flotation has been able to separate triplet materials from graphite to some extent, but there are still many problems to be solved in the separation of LiFePO4 from graphite. In this study, a novel flotation reagent regime was proposed to enhance the flotation separation performance of LiFePO4 and graphite electrode materials by carbonaceous surface selective inhibition, which were achieved by H acid as a depressor. The flotation results showed that under the flotation conditions of pH value 9.3 ± 0.1, 10.0 mg/L n-dodecane, 7.5 mg/L MIBC, and 250 mg/L H acid, the recovery of LiFePO4 and graphite were 11.95 % and 94.28 %, respectively. The adsorption kinetic model showed that the adsorption speed of LiFePO4 electrode material is higher than graphite, the adsorption isothermal model showed that the adsorption capacity of LiFePO4 electrode material is significantly higher than graphite. The results of X-ray photoelectron spectroscopy showed that the interaction between H acid and LiFePO4 or graphite electrode material is mainly π-π interaction. Raman spectroscopy analysis showed that the carbon disorder degree and skeleton form of the graphite and LiFePO4 are significantly different, which makes H acid more easily adsorbed on the surface of LiFePO4. This study provided a new method for the efficient separation and recovery of LiFePO4 and graphite electrode materials from spent lithium iron phosphate batteries.

Effective purification of the low-rank coal by the collaboration of the microemulsion collector and the CO2 nanobubbles

As the inferior hydrophobicity and low probability of bubble-particle collision, the low-rank coal has poor flotation performance. In this paper, an effective purification method that innovatively combined the use of the microemulsion collector and the CO2 nanobubbles was proposed. The procedure of the purification method and the reagent regime were established through flotation tests. And the flotation results showed that in the presence of the CO2 nanobubbles, a satisfactory separation performance with 83.97 % of combustible matter recovery was obtained at a microemulsion collector consumption of 3.5 kg/t. The collector consumption decreased significantly compared with the diesel oil. The interaction mechanism was elucidated through the Zeta potential measurements, the rheological behavior tests, the fractal dimension analysis, and the extended Derjaguin–Landau–Verwey–Overbeek theoretical analysis. On one hand, the microemulsion collectors can reinforce the adsorption of the oily collectors on the low-rank coal surface to improve its hydrophobicity. On the other hand, the agglomeration of the coal particles was strengthened and the probability of bubble-particle collision was increased due to the selective adsorption of CO2 nanobubbles on the hydrophobically modified surface of the low-rank coal. This research provided new insight into the improvement of the low-rank coal flotation.

Варианты эффективного применения побочных продуктов нефтепереработки и нефтехимии в процессе флотации труднообогатимых и высокозольных каменных углей

The article deals with the development of effective reagents for flotation of hard-to-enrich and high-ash coal with a high content of fusene elements. The results of studies of the physicochemical properties of this coal are presented: sieve and fractional compositions, petrographic and refrectogram analyses of the coal under study, as well as ash content. It is difficult to obtain concentrates during flotation with ash content satisfying coke chemical production using known flotation reagents. Reagent regimes with the use of flotation reagents based on petrochemicals and oil refining intermediates have been studied, which show high efficiency in flotation of hard-to-enrich and high-ash coals. Scientific substantiations of their effectiveness are presented.

Prediction model of iron reverse flotation tailings grade based on multi-feature fusion

During the production of iron in reverse flotation, obtaining real-time froth grade values helps to adjust the reagent regime to ensure the quality of the beneficiated product and save production costs. In predicting the froth grade, it is necessary to segment the froth image to extract bubble size features. In this study, an improved U-net algorithm with a focus mechanism is proposed to effectively avoid under-segmentation and over-segmentation and to extract bubble size features. Through the analysis, the bubble color features that are beneficial to the rank prediction are identified. A multi-feature fusion deep neural network model based on Resnet is established to predict the bubble grade values. The test results indicate that with sufficient accuracy, the model can be employed in reverse flotation production.

Optimized regimes of nepheline flotation using stockpiled apatite-nepheline processing waste (the Khibiny deposits)

The task of processing stockpiled apatite-nepheline waste is of relevance and in line with the goal of ensuring environmental safety in Russia’s Arctic zone achievable through the reduction of accumulated environmental damage. The cost of processing secondary raw materials — when no grinding is required and thus most energy costs are saved — is much lower in comparison with the processing of natural raw materials. Around 1 billion tons of flotation waste have accumulated in the tailings ponds of Apatit-owned concentrator plants over the 90-year history of exploiting the Khibiny deposits. It poses a real threat of toxic pollution. In this regard, the development of beneficiation processes aimed at reducing waste that goes in the tailings ponds should be considered a priority area of research in the field of mineral processing. This paper describes the results of an extended laboratory study that looked at the concentratibility of two samples of apatite-nepheline flotation waste taken from two tailings ponds owned by Apatit which have different storage times. It is shown that the main valuable minerals in the tailings include nepheline (more than 50%), pyroxenes (5–7%) and titanite (about 4%). Three reagent regimes of reverse flotation were used to obtain nepheline concentrate: a basic regime that uses a mixture of coniferous and deciduous tall oil; a regime that uses alkyl hydroxamic acids to which distilled tall oil is added, and a regime that uses a mixture of tall oil and polyalkyl benzene sulfonic acids. The findings suggest that the regime that uses the mixture of alkyl hydroxamic and carboxylic acids with the addition of distilled tall oil provides the most efficient flotation regime that helps to selectively separate nepheline and darkcoloured minerals from the long-term storage tailings. The paper demonstrates feasibility of using apatite-nepheline processing waste (a case study of the Khibiny deposits) to produce nepheline concentrate, which serves as a material that can substitute imported non-bauxite raw materials required by aluminium industry.

Improvement of the reagent regime for the flotation enrichment of polyhalite ores

The effect of foaming agents of different chemical nature (amyl alcohol, glycolic ether, pine oil) on the flotation of halite from polyhalite ores using alkylmorpholine as a collector was investigated. It was established that the combined adding of amyl alcohol with alkylmorpholine and glycolic ether with alkylmorpholine in the process of sodium chloride flotation allows achieving high technological performance and reduces the consumption of expensive alkylmorpholine by 2 times. The use of pine oil as a foaming agent in a mixture with alkylmorpholine has been established to reduce the collector consumption by 2.2 times.

Flotation of sulfide lead-zinc ores of the Akzhal deposit

Ore samples from various sections of the underground mine at the Akzhal deposit were studied. The ore mineralization is relatively evenly distributed and is represented by pyrite, sphalerite, and galena. Studies were carried out to reduce the zinc content in the lead concentrate during selective flotation of sulfide lead-zinc ores. The possibility of adjusting the reagent regime using a mixture of zinc sulfate and sodium thiosulfate was studied. The findings indicate the optimal grinding fineness of 62 % –0.074 mm. This value ensures the most acceptable process indicators: the mass fraction of lead in the lead concentrate of 13.19 % with the recovery of 94.89 % and the mass fraction of zinc of 5.36 % with the recovery of 26.65 %. The mass fraction of zinc in the zinc concentrate is 26.54 % with the recovery of 54.41 %. Closed-cycle flotation of lead-zinc ore was conducted using 2 : 1 and 5 : 1 zinc sulfate and sodium thiosulfate mixtures as a depressant for zinc minerals in the lead cycle. With the first ratio, the mass fractions in the lead concentrate were 69.23 % for lead and 8.52 % for zinc and the mass fractions in the zinc concentrate were 57.60 % for zinc and 1.65 % for lead. With the second ratio, the mass fractions in the lead concentrate were 68.12 % for lead and 9.12 % for zinc (compare with 10.10 % with the plant inhouse reagent regime). The mass fractions in the zinc concentrate were 56.80 % for zinc and 1.72 % for lead.

Hydrogen Peroxide in Reagent Regimes in Copper Sulphide Ore Flotation

Hydrogen Peroxide in Reagent Regimes in Copper Sulphide Ore Flotation

Hydrogen Peroxide in Reagent Regimes in Copper Sulphide Ore Flotation

Hydrogen Peroxide in Reagent Regimes in Copper Sulphide Ore Flotation

Effect of electroflotation on quartz and magnetite and its utilization on the reverse flotation of magnetic separation concentrate

In this study, the electroflotation of quartz and magnetite with cationic collector dodecylamine (DDA) and anionic collector sodium oleate (NaOL) were investigated to gain a better understanding of the electroflotation process and identify methods to improve it. An interesting phenomenon accompanied with obvious promotion (NaOL is used as collector) and inhibition (DDA-HCl is used as collector) of quartz flotation was observed after electrolysis. The obvious promotion arouse from the supply of the metal cations as active site for the adsorption of negatively charged group and increase active collecting species ionic forms RCOO- and (RCOO)22–. Conversely, the obvious inhibition originated from the decrease of the active collecting species RNH3+ and (RNH3)22+. An obvious inhibition phenomenon was observed after the electrolysis for the magnetite. This is because the active collecting species RNH3+, (RNH3)22+, RNH2·RNH3+ and RCOOH molecule decreased significantly after electrolysis. Furthermore, a comparison test between the regular flotation and electroflotation was conducted in the reverse flotation of magnetic separation concentrate. Compared with the regular flotation process, electroflotation flotation was characterized by simple reagent regime (without pH regulator and activator) and moderate conditions (natural pH), which had mild operation condition superiority. Moreover, the flotation product index of electroflotation can be better through slightly adjusting the reagent regime, and it can be certain that electroflotation is an effective process in the reverse flotation of magnetite. These findings provided a novel perspective for understanding the electroflotation process.

Recovery of Catapleiite and Eudialyte from Non-Magnetic Fraction of Eudialyte ore Processing of Norra Kärr Deposit

Eudialyte ores from Norra Kärr (Sweden) and Kringlerne (Greenland) are considered a potential source of rare-earth elements (REE) for the development of a sustainable REE industry outside China. Magnetic separation is successfully applicated to recover eudialyte as a magnetic fraction. In the case of the Norra Kärr deposit, up to 20% of the REE and up to 40% of the Zr are lost during mineral processing in the non-magnetic fraction. Zr and REE are associated with non-magnetic minerals such as catapleiite, low- or non-magnetic eudialyte species, and both their intergrowths. Besides zirconosilicates such as catapleiite and eudialyte, the non-magnetic fraction has valuable and already-liberated minerals such as alkali feldspars and nepheline, which should not be considered as tailings. In this investigation, a possible way to recover REE bearing zirconosilicates from the non-magnetic fraction using flotation is presented. First, a low-grade eudialyte concentrate (1.8% Zr, 0.94% REE) from ground ore was obtained using magnetic separation. The non-magnetic fraction was then treated using froth flotation, and a Zr-REE bearing product (9% Zr, 1.5% REE) was obtained as froth product. For this purpose, phosphoric acid esters were used as selective collectors for zirconosilicates at a pH between 3.5 and 4.5. The reagent regime could be proposed not only to recover Zr- and REE-bearing minerals, but also simultaneously to remove Fe, Ti, and other colored impurities from the nepheline-feldspar product and to minimize the tailings volume.

Improvement of the fine coking coal flotation technolgy

The paper presents data on the development of a reagent regime for the flotation of fine coal fractions of –0.5+0 mm. The study focuses on coking coal from the Butovskaya mine (Kemerovo coal deposit, Russia). The ash content in the rock mass mined ranges from 23 to 30 %. Using the methods of optical microscopy, the presence of rock-forming minerals in the flotation feed, mainly represented by silicates (quartz), was established, which supports the addition of liquid glass to the process as a depressant for silicates. The study of the flotation kinetics allowed establishing the coal flotation time for a more complete recovery of the combustible matter. The paper compares the basic and alternative reagent regimes. The basic regime is represented by an apolar collector in the form of a mixture of hydrocarbon liquids of petroleum origin and a frother containing oxygen-bearing chemical compounds of various molecular structures in its group chemical composition. The alternative regime includes a depressant (liquid glass), an apolar collector (diesel fuel), and a frother represented by a mixture of aliphatic alcohols, ethers, and esters. Using the technology developed, coal flotation concentrate was obtained with the mass fraction of ash of 7.36 % and recovery of 9.78 %, allowing to generate a product meeting the requirements of GOST R 51588-2000.The work was carried out with the support of the Russian Science Foundation (project No. 19-17-00096).

НИЗКОРАЗМЕРНЫЕ СТРУКТУРЫ БЛАГОРОДНЫХ И ЦВЕТНЫХ МЕТАЛЛОВ И МЕТОДЫ ИХ СЕЛЕКТИВНОЙ СЕПАРАЦИИ

There is a worldwide trend of increasing the share of extraction and processing of low-grade minerals, but their extraction and processing volumes are still low. There are several reasons for this: high mining and transportation costs, imperfect techniques and technological difficulties in enrichment and processing of refractory and low-quality minerals. Due to the depletion of reserves of easily beneficiated raw materials and to compensate for the growing shortage of high-quality minerals, the Russian mining industry development strategy provides for the involvement of new and unconventional types of deposits into production. Examples of such deposits are deposits of carbonaceous raw materials (black shale, refractory sulphide carbon-bearing ores, impactites, etc.) containing carbon of varying degrees of metamorphism. On the basis of the most modern mineralogical, physical, nuclear and chemical methods of research of composition, structure and properties of the carbonaceous raw materials at the micro- and nanolevel, the composition of the productive mineral matter, physical, chemical and thermodynamic laws of separation of valuable mineral components and the basic technological processes to obtain the finished product for valorization of the unconventional carbonaceous mineral raw materials were determined with maximum reliability. One of the possible reasons of difficulty of beneficiation of carbonaceous raw materials is the fine phenocrysts in graphite which can be solved by using the flotation process. Contrast of surface properties of minerals with similar technological properties can be increased by application of different energy effects (MEMI, MIO, microwave, electrochemical treatment etc.) at successive stages of raw material transformation, regulation of pulp conditioning conditions (duration and intensity of agitation, heat treatment of pulp) as well as by development and application of selective reagent regimes. The special feature of flotation as a method of extraction of noble and rare metals is the ability to extract valuable metals not only in their native free form, but also in close association with sulphides and carbon. Flotation with the use of intensifying influences made it possible to transfereven low-sized structures of noble and rare metals, which are not extracted by conventional methods of cyanidation, gravitation enrichment and amalgamation, into the concentrate. One of the ways to increase the efficiency of the flotation process is preliminary modification of the additive which is introduced in addition to the main reagents of the sinter - “carrier material”.