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1

The removal of dolomite from collophane using reverse flotation process enhanced by compound collector

Liu Liu, Tian Mengjie, Deng Xiangyi, Luo Huihua, Chi Ruan, Wu Kang

Physicochemical Problems of Mineral Processing

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2023

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Vol. 59, iss. 1

art. no. 159965

EN

To improve the magnesia removal effect of collophane and increase the P2O5 grade of phosphorus concentrate, the fatty acid collector mixed with sodium dodecyl sulfate (SDS) was used as the compound collector in reverse flotation for magnesia removal in acid system. Solution surface tension measurement, Zeta potential test and infrared spectrum analysis were conducted to analyze the intensified effect of compound collector for dolomite removal. The results showed that under the conditions of grinding fineness -0.074 mm accounted for 89.8%, sulfuric acid dosage 12.0 kg/t, phosphoric acid dosage 3.0 kg/t, SDS compound proportion 3%, collector dosage 1.0 kg/t, the P2O5 grade of concentrate is increased from 25.7% to 29.94%. SDS can reduce the surface tension of slurry, which is conducive to the formation and stability of flotation foam. Zeta potential became negative due to the compound collector adsorbed on the mineral surface. Moreover, the -CH2 antisymmetric stretching vibration peak originated from fatty acid and SDS were detected after the interaction of collectors with dolomite. The compound collector was effectively adsorbed on the surface of dolomite, enhancing the magnesium removal effect of collophane.

2

Utilization of coal slime: Coal and kaolinite separation by classification, forward and reverse flotation method

Shen Liang, Qiao Erle, Liu Lingyun, Xue Changguo, Liu Binghe, Min Fanfei

Physicochemical Problems of Mineral Processing

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2022

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Vol. 58, iss. 3

art. no. 147742

EN

Coal slime is not only a solid waste, but also a source of energy. With the improvement of environmental protection requirements, the comprehensive utilization of slime has become an urgent problem for coal preparation plants. In this paper, we put forward a promising way of coal slime resource utilization. X-ray diffraction (XRD), X-ray fluorescence spectrometer (XRF) and laser particle sizer was used to analyze the properties of coal slime. Obtained results showed that the slime was mainly composed of the coal, kaolinite and quartz with a particle size of -100 μm. Most kaolinite minerals can be enriched in overflow when the feed pressure is 0.2 MPa by using hydrocyclone. 21.3% clean coal with ash content of 12.3% and 33.46% kaolinite with particle size of -5 μm can be recovered by forward flotation and reverse flotation respectively. Coal water slurry with 61% concentration can be prepared from reject of forward flotation and concentrate of reverse flotation at shear rate of 100 s-1. This study has an important practical application value in clean and efficient utilization of coal.

3

Separation of magnesite and calcite based on flotation solution chemistry

Yao Jin, Gong Xiufeng, Sun Haoran, He Ruofan, Yin Wanzhong

Physicochemical Problems of Mineral Processing

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2022

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Vol. 58, iss. 4

art. no. 149398

EN

The dissolution characteristics of minerals, dissolution of flotation agents in solutions, and equilibrium of dissociations and associations serve as the basis for determining the optimal conditions for the effective components of flotation agents and for evaluating the interaction between flotation agents and minerals. This basis provided the theoretical support for the flotation separation of minerals. Based on this, the flotation separation of magnesite and calcite was realized using sodium dihydrogen phosphate, also known as monosodium phosphate (MSP), as a regulator and dodecylamine (DDA) as a collector. When MSP was used in the DDA system, single-mineral and binary mixed-ore flotation tests revealed that the floatability of calcite was significantly greater than that of magnesite and the separation of magnesite and calcite was more effective, respectively. Zeta potential measurements showed that MSP-containing negative groups could selectively reduce the zeta potential of calcite and promote the adsorption of DDA-containing positive groups on the surface of the calcite. However, this effect was negligible on the zeta potential of magnesite. Due to the stronger affinity of MSP to Ca2+ than that to Mg2+, as demonstrated by Fourier transform infrared and X-ray photoelectron spectroscopy analyses, the MSP was adsorbed onto the surface of calcite primarily by hydrogen bonds rather than magnesite, which promoted the stronger adsorption of DDA-containing positive groups on the surface of the calcite. As a result, the differences in the floatability of magnesite and calcite were enlarged by MSP. Thus, MSP can be utilized an effective regulator for the efficient separation of magnesite from calcite via reverse flotation.

4

Influences of process water chemistry on reverse flotation selectivity of iron oxides

Tang Min, Wang Dong, Wu Yan, Liu Dianwen

Physicochemical Problems of Mineral Processing

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2022

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Vol. 58, iss. 6

art. no. 151839

EN

It is critical for water quality in flotation as it dramatically influences the chemical/electrochemical properties of mineral surfaces and their interactions with reagents. Many potential variations could alter the water chemistry: water recirculation, mineral dissolutions, reagent additions, etc. This study aimed to identify the key elements from the recycled water sources affecting the separation efficiency in a typical industrial flotation circuit of iron oxides through a series of bench/micro flotation tests, zeta potential measurement, etc. The built-up and distribution of the dominant cations/anions in the process water from the roughers in the flotation system was also analyzed and recorded by Inductively Coupled Plasma-Optical Emission (ICP-OES) for a period of about three months when the operations were stable. The flotation results pointed out that a concentrate with a sharp increase of 6.0% Fe recovery and 2.5% SiO2 content was obtained by using the recycled tailing water only in comparison by using fresh water. In contrast, a slight uptrend in the grade of Fe but a substantial loss of near 6.5% Fe recovery occurs by using the treated sewage water alone instead. This could attribute to the ion distributions in these water sources, in which Ca2+, Fen+, Mg2+ or SO42ions were determined as the key ions influencing the flotation behaviors of the iron ore. But the competitive effects of Fe3+ ions were more significant than the ones of Ca2+ or Mg2+ ions. And the occurrence of starch could deteriorate the dilution of silicates in concentration induced by Fe3+/Fe2+ ions. It can be explained by zeta potential measurement or solution chemistry of those ions, indicating that at 8.5-9.0, the coating of the precipitates of Fe(OH)3(s) induced by iron ions alters a reverse on the zeta potentials of quartz. The presence of SO42-ions, however, has a positive role in reducing the possibility of slime coating on silicates due to acting as a chelating agent of iron ions.

5

Flotation separation of quartz from phosphorite using an imidazole ionic liquid collector and its adsorption mechanism

Zhao Yuanyuan, Xu Wei, Mei Guangjun, Yu Mingming, Yang Siyuan, He Zhan

Physicochemical Problems of Mineral Processing

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2022

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Vol. 58, iss. 1

159--168

EN

In this study, an imidazole ionic liquid (dodecyl-tri-methylimidazolium chloride) was employed as a collector to separate quartz from phosphorite. The micro-flotation experiments of a single mineral found that it had selective collecting ability for quartz than phosphorite. Mixed mineral flotation experiments confirmed that efficient separation results could be obtained using the imidazole ionic liquid as the collector. A concentrate with a 31.44% grade of phosphorite could be obtained with a 0.285 kg/Mg collector dosage at neutral pH, which was much better than the traditional collector dodecylamine. The adsorption mechanism of the imidazole ionic liquid on the surface of phosphorite and quartz was investigated by contact angle and zeta potential measurements, Fourier transform infrared and X-ray photoelectron spectroscopy analyses. These results showed that the adsorption of imidazole ionic liquid at the quartz surface was stronger than that of phosphorite, and the collector adsorbability difference between quartz and phosphorite resulted in the efficient flotation separation. Consequently, the dodecyl-tri-methylimidazolium chloride salt is an effective collector for reverse flotation of quartz from phosphorite.

6

Application of uniform test design in optimizing the flotation reagents of iron anionic reverse flotation circuit

Hou Ying, Sobhy Ahmed

Physicochemical Problems of Mineral Processing

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2022

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Vol. 58, iss. 1

37--49

EN

Most iron reserves are low in grade with quartz as the main gangue mineral, and anionic reverse flotation has become the most crucial separation method in the processing plants of iron ore. Thus, a flotation feed sample that is a mixture of low-intensity and high-gradient magnetic separators concentrates was acquired from a processing plant. The sample characterizations with X-ray diffraction (XRD), X-ray fluorescence (XRF), laser particle size analyzer, and mineral liberation analysis (MLA) confirmed that the sample consists of iron oxide as a valuable mineral and quartz as a gangue mineral with adequate liberation degree. In the anionic reverse flotation, the interaction of the flotation reagents with the constituents of the feed makes the flotation a complex system. Thus, the selection and optimization of regent dosages were performed using a uniform experimental design to estimate the optimum separation efficiency. The optimum reagent system was 1.6 kg/Mg starch depressant, 1.0 kg/Mg calcium oxide (lime) activator, and 0.8 kg/Mg TD-II anionic collector. At the optimum, 68.90% iron grade with 92.62% recovery was produced.

7

The mechanism study on deep eutectic solvent for desilication of magnetite by reverse flotation

He Zhan, Liu Cai, Mei Guangjun, Zhao Yuanyuan, Cheng Qian, Song Xianwei

Physicochemical Problems of Mineral Processing

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2021

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Vol. 57, iss. 6

12--22

EN

Magnetite reverse flotation using a new deep eutectic solvent synthesized by lactic acid and CTAC as the collector has been investigated in this work. The flotation test results were compared with dodecylamine. The CTAC/lactic acid DES increased the grade of total iron to 66.69%, and the reduce quartz content to 6.67%, which were preferable to dodecylamine (the grade of Fe in the concentrate is 63.47%, and the grade of quartz in the concentrate is 9.13%). The depression performance and adsorption mechanism of CTAC/lactic acid DES on surface of magnetite and quartz are investigated by FT-IR, zeta potential and XPS. The results show that the adsorption of CTAC/lactic acid DES on quartz surface is more effective than that of magnetite. Therefore, deep eutectic solvent is an effective reagent for reverse flotation of magnetite as collector.

8

Significance of reagents addition sequence on iron anionic reverse flotation and their adsorption characteristics using QCM-D

Hou Ying, Sobhy Ahmed, Wang Yue

Physicochemical Problems of Mineral Processing

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2021

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Vol. 57, iss. 1

284--293

EN

To explore the influence of reagents addition sequence of the pH regulator and the starch depressant on the anionic reverse flotation of iron oxide, flotation conditional experiments were performed on mixed low-intensity and high-gradient magnetic concentrates which is the flotation feed acquired from the iron processing plant. Besides, quartz crystal micro-balance with dissipative (QCM-D) was conducted to detect the adsorption phenomena of the flotation reagent on iron oxide sensors at different addition orders. The outcomes showed that the flotation performance using the pH regulator prior to the depressant was the best. For example, at 1.6 kg/Mg starch dosage, the recovery and separation efficiencies were improved by 18.3% and 21.2%, respectively, with keeping the concentrate Fe grade as high as 69.5%. Also, QCM-D frequency shifted by -41 Hz from 17 Hz to -24 Hz with increased dissipation from -2.6 x 10-6 to 8.2 x 10-6, indicating an increase in the mass of slightly-rigid starch adsorption layer on the surface of iron oxide under a strong alkaline condition with adsorption density of about 0.46 mg/cm2. On the other hand, under weak alkaline conditions, starch was adsorbed, and then the starch was desorbed upon the addition of the strong alkaline solution. Whereas, adding the pH modifier to create a strong alkaline condition enhanced the starch adsorption significantly with coordination and hydrogen bonds, and prevented the following adsorption of the anionic collector for more efficient reverse flotation of iron oxide minerals.

9

Reverse flotation of iron ore using amphoteric surfactant: 2-((2(decyloxy)ethyl)amino)lauric acid

Luo Binbin, Zhu Yimin, Sun Chuanyao, Li Yanjun, Han Yuexin

Physicochemical Problems of Mineral Processing

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2021

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Vol. 57, iss. 3

73--83

EN

2-((2-(decyloxy)ethyl)amino)lauric acid (C10H21CH(NH(CH2)3OC10H21)COOH, (LDEA), a novel amphoteric surfactant, has been first utilized as the collector for on-site the reverse flotation of Anqian mixed magnetic concentrates. The separation performances were investigated systematically by flotation conditioning tests, open-circuit flowsheet experiment, and locked cycle flowsheet test. The flotation condition test's results showed that the optimal roughing conditions were pulp pH of 10, starch dosage 1000 g/Mg, and LDEA dosage of 500 g/Mg at 25 °C. Under the optimized flotation conditions, through one roughing - three scavengings locked cycle flowsheet, the iron concentrate with a total iron grade of 68.08% and recovery of 88.20% was obtained. In contrast, the iron grade of the tailings was only 12.32%. Compared with the flotation results of anionic commercial surfactant RA-715 used as the collector, the LDEA has a better separation performance. The iron grade and recovery increased by 0.07% and 0.86% in the iron concentrate, and the grade of the tailings decreased 3.72%, respectively. Besides, the LDEA possesses more advantages, such as a simple flotation process, no activator (CaO) addition, lower collector consumption, and lower pulp temperature. The study revealed that the novel amphoteric surfactant LDEA was an effective flotation collector with good collecting and separation ability on natural iron ores at a comparatively lower temperature.

10

Reverse flotation of collophanite at natural pH using isooctyl polyoxyethylene ether phosphate as a collector

Li Hongqiang, Zhang Wen, Chen Qian, Huang Peng, Kasomo Richard M., Zou Ze, Weng Xiaoqing, He Dongsheng, Yang Siyuan, Song Shaoxian

Physicochemical Problems of Mineral Processing

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2021

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Vol. 57, iss. 4

78--86

EN

Reverse flotation of collophanite at natural pH could significantly decrease the cost of pH regulators. In this study, isooctyl polyoxyethylene ether phosphate (AEP) was tested as a new surfactant in the reverse flotation of collophanite. Micro-flotation tests were conducted, and the adsorption mechanism of the new collector was analysed using X-ray photoelectron spectroscopy (XPS) and zeta potential analyses. The results of the flotation tests demonstrated that AEP could enable dolomite to float under natural pH (pH=7.2) and showed profound selectivity towards dolomite as opposed to fluorapatite. Based on the zeta potential and XPS results, the adsorption phenomena are mainly attributed to calcium active sites on both mineral surfaces. Dolomite possesses more magnesium active sites than fluorapatite, which tend to reinforce the interaction effect between AEP and dolomite. Furthermore, when compared to CO32- ions on the dolomite surface, PO43- ions on the fluorapatite surface tend to exhibit a stronger hindrance to the adsorption of AEP on the fluorapatite surface. This is attributed to their larger volumes and more charges on their surfaces, thereby causing a floatability difference between the two minerals.

11

Investigations on a novel collector for anionic reverse flotation separation of quartz from iron ores

Fang Ji, Ge Yingyong, Liu Shunbing, Yu Jun, Liu Cheng

Physicochemical Problems of Mineral Processing

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2021

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Vol. 57, iss. 1

136--155

EN

It is necessary to exploit an easy and effective way to obtain flotation collector. In this paper, oleic acid was modified by oxidation reaction to obtain an excellent collector. The ﬂotation performances of oleic acid and its oxidation products were systematically investigated and a novel collector ((E)-8,11-dihydroperoxyoctadec-9-enoic acid, EDEA) was obtained. Single mineral flotation tests results showed that EDEA had strong flotation power towards quartz at pH＞11 and hardly floated hematite and magnetite at pH=8~13. The recovery of quartz could achieve 92.35% with 120 mg/L EDEA under the condition of pH=12 and dosage of CaCl2 60mg/L while the recovery was 62.44% with 120 mg/L oleic acid. Bench scale flotation tests results showed that EDEA had a preferable effect on separating quartz from iron ore especially at low flotation temperature (288K). The mechanism research revealed that EDEA attracted on quartz surface through electrostatic attraction and the neighboring EDEA molecules could form intermolecular hydrogen bonds which resulted in a closer alignment of EDEA on quartz surface.

12

QSAR study of amine collectors for iron ore reverse flotation

Wang Benying, Xu Xinyang, Duan Hao, Wang Xinyang

Physicochemical Problems of Mineral Processing

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2019

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Vol. 55, iss. 5

1059--1069

EN

In order to reveal the relationship between flotation behaviors of collectors and their structures, quantitative structure–activity relationship (QSAR) study about separation efficiency of quartz from hematite using amine collectors was performed. The genetic function approximation (GFA) algorithm was applied to generate the correlation models and model with acceptable R2 and Rcv2 (cross validated R-squared) correlation coefficients (R2=0.9666, Rcv2=0.9201) was developed. The model revealed that the Lowest Unoccupied Molecular Orbital (LUMO) energy of the molecule, the charge of nitrogen and the electronegativity of polar group were the major factors that affected the separation efficiency of collectors. The higher nitrogen charge, the larger electronegativity of polar group and the more positive of LUMO energy of amine collectors were, the higher separation efficiency would be.

13

Flotation behavior and separation mechanism of quartz and iron minerals in α-bromolauric acid reverse flotation system

Han Y., Guo W., Zhu Y., Wei Y., Gu X.

Physicochemical Problems of Mineral Processing

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2018

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Vol. 54, iss. 3

992--1003

EN

A new type collector α-Bromolauric acid (α-BLA) had been proved to be an efficient collector for quartz flotation. However, the effects of α-BLA on the flotation behavior of iron minerals and quartz-iron separation had not been investigated. In this study, collector α-BLA was synthesized in the laboratory. The flotation behavior of quartz, hematite and magnetite under α-BLA reverse flotation system were investigated and the separation mechanism of quartz-irons was studied by contact angle, zeta-potential and infrared spectroscopy. The results showed that the optimum flotation pH was 11.5 for quartz, 6.45 for hematite and 6.97 for magnetite. The best α-BLA concentrations was 75 mg/dm3 for quartz flotation, 125 mg/dm3 for hematite and magnetite flotation. The activator CaCl2 had little effect on the flotation of hematite and magnetite, but the minimum dosage 50 mg/dm3 of activator CaCl2 was necessary for quartz flotation. On the contrary, starch had no effect on the flotation of quartz, while the recoveries of magnetite and hematite tended to be 0% as starch concentration more than 80 mg/dm3. The separation mechanism of quartz from iron minerals under α-BLA reverse flotation system was that the starch could be selectively adsorbed on the surface of hematite and magnetite in the form of strong hydrogen bond adsorption. However, the same adsorption of starch did not occur on the surface of quartz, so the α-BLA can be successfully adsorbed on the surface of activated quartz to make the quartz strongly hydrophobic, and then to be floated out.

14

Reverse flotation of ultrafine magnetic concentrate by using mixed anionic/cationic collectors

Lu D., Hu Y., Li Y., Jiang T., Sun W., Wang Y.

Physicochemical Problems of Mineral Processing

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2017

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Vol. 53, iss. 2

724--736

EN

Compared to reverse cationic flotation, the advantages of reverse anionic flotation include relatively lower sensitivity to slimes and lower reagent cost. Besides, anionic collectors were found to have excellent capability of selectively separating an ultrafine magnetite ore. Addition of a small amount of cationic collector into the anionic collector as the collector mixture can improve the metallurgical results of removing silicates in reverse flotation. In this paper, NaOL and DDA were used for reverse flotation of the ultrafine magnetic concentrate. The separation performance of the collector mixture was investigated at different ratios of NaOL and DDA. The results showed that a better separation performance was obtained for the collector mixture than for NaOL alone. There was an optimal molar ratio between NaOL and DDA equal to 10:1. In the flotation system with the presence of the collector mixture, the good selectivity was found when starch was used as a depressor for magnetite and CaO was used as an activator for quartz. The influences of starch and CaO dosages on the separation performance of magnetite, quartz and chlorite had been investigated through micro-flotation tests. The infrared spectral analysis showed stretching vibration peaks of chemical adsorption of the collector mixture on the magnetite surface. The peaks were not present when starch was used as the depressor for magnetite. The closed flotation tests on the magnetic concentrate with the particle size of -25 μm were performed in the laboratory. The Fe concentrate assaying 64.52 % was obtained with Fe recovery of 80.66%, for the Fe content of feed equal to 52.98%.

15

Properties of fatty acid/dodecylamine mixtures and their application in steam coal reverse flotation

Shen L., Wang H.

Physicochemical Problems of Mineral Processing

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2016

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Vol. 52, iss. 1

303--316

EN

A series of surfactant mixtures which consist of DAH (dodecylamine hydrochloride) and fatty acids (FAD) were made in this study. The characteristics of these fatty acids/DAH mixtures, including surface tension, critical micelle concentration (CMC) and adsorption onto coal were investigated. The reverse flotation results with these fatty acids/DAH mixtures (FAD) and DAH were compared with each other. Experimental results showed that the fatty acids/ DAH mixtures have lower CMC and γcmc than DAH. The adsorption test indicated that more amine molecules would adsorb preferentially onto the bubbles surface in FAD solutions than that in DAH solutions. Reverse flotation results showed that about 50% surfactant dosage was saved under the same froth product yield. Only 28% froth product yield was obtained in the presence of 1.66 kg/Mg DAH. However, when 0.83 kg/Mg hexadecanoic acid/DAH mixture (C16D) surfactant was used, the froth product yield reached 29%. Dodecanoic acid/DAH mixture (C12D) surfactant a showed better performance with a high mineral matter recovery similar to that with tetradecanoic acid/DAH mixture (C14D) and higher combustible recovery than with C14D and C16D.

16

Lignite cleaning in NaCl solutions by the reverse flotation technique

Zhang H., Liu Q.

Physicochemical Problems of Mineral Processing

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2015

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Vol. 51, iss. 2

695--706

EN

A cleaning possibility of low (BD) and high ash content (IM) lignites in NaCl solutions using a reverse flotation technique was studied. Preliminary test results indicated that BD lignite cannot be cleaned effectively in the traditional manner because gangue was floated first rather than a combustible material. Further studies indicated that the lignite cleaning in NaCl solutions using the reverse flotation technique is possible. However, a large quantity of dodecyl amine hydrochloride (DAH) was required. A lower ash content in a concentrate can be obtained by addition of NaCl. A concentrate yield can be im-proved by addition of starch. Under the test conditions, for BD lignite with the ash content in the feed 15.19%, the ash content in the concentrate 11.44% and the concentrate yield 67.38% were obtained. Similarly, for IM lignite with the ash content in the feed 57.40%, the ash content in the concentrate 32.90% and the concentrate yield 25.08% were obtained. The flotation rate constant k and maximum ash recovery ε∞ significantly increased with the NaCl concentration.