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1

Study on the separation effects of the novel collector ODD on magnesite and quartz

Gao Gui, Sun Haoran, Wang Yulian, Sun Yishen, Han Huili, Yuan Zhigang

Physicochemical Problems of Mineral Processing

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2024

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Vol. 60, iss. 4

art. no. 190522

EN

Traditional magnesite desilication flotation collectors struggle to efficiently remove quartz from low-grade magnesite, prompting the exploration of new, highly selective flotation collectors. Addressing this need has become a focal point in mineral processing research. This study introduced heptadecylamine ethylimidazoline quaternary ammonium salt (ODD) as a quartz flotation collector for separating quartz from magnesite. Flotation experiments involving single minerals and artificially mixed minerals demonstrated that magnesite and quartz could be effectively separated under specific conditions: an ODD concentration of 40mg/L and pH=7.0. Zeta potential assessments revealed that the adsorption of ODD increased the potential of quartz by 4.4 times compared to magnesite. Furthermore, contact angle measurements illustrated that ODD selectively increased the hydrophobicity of the quartz surface while not affecting the contact angle of magnesite. X-ray photoelectron spectroscopy (XPS) analysis indicated that ODD's selective adsorption at the quartz surface through interaction with the O sites on quartz rather than magnesite. Drawing from these findings, a flotation separation model from magnesite and quartz under the influence of ODD was formulated.

2

Effect of ultrasonic pretreatment on flotation purification of quartz

Deng Jiabao, Luo Dawei, Bai Junzhe, Rong Ke

Physicochemical Problems of Mineral Processing

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2024

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Vol. 60, iss. 3

art. no. 190008

EN

Quartz sand purity dictates its applications, with current research focusing on flotation purification. To investigate the effects of ultrasonic pretreatment on quartz flotation, an RKIII single-tank flotation machine was employed at a neutral pH of 6.8, and the impacts of varying ultrasonic powers (120-300 W) and different treatment durations (0-25 min) were discussed. Additionally, ultrasonic pretreatments were carried out in acidic and alkaline environments simulated by 1%-5% solutions of hydrochloric acid and sodium hydroxide, respectively. Through the analysis of impurity content in quartz sand, it was found that under natural pH conditions and a power range of 120-300 W, the optimal purification effect was achieved by adding 100 g of quartz sand to 1200 cm3 of deionized water and subjecting it to ultrasonic treatment for 10-15 min. As the ultrasonic power increased, the purification effect was enhanced. The results showed that the removal of Fe2O3, TiO2, and Al2O3 was increased by 10.4%, 3.3%, and 1.2%, respectively, compared with that of the conventional flotation after ultrasonic pretreatment for 15 min with ultrasound power 240 W in a neutral environment. In the optimal 5% HCl solution, the removal rate of Fe2O3 was 11.2% and 21.6% higher than that of the control group and the untreated group, respectively. The removal rate of TiO2 was 4.6% and 7.9% higher, respectively. The removal rate of Fe2O3 increased by 23.2% and that of TiO2 increased by 9.1% with 240 W ultrasonic treatment in 4% NaOH solution.

3

Application of dodecyl amine/dodium petroleum sulfonate mixed collector in quartz-feldspar flotation separation

He Yuhao, Ren Zijie, Zhu Huimin, Zheng Renjun, Li Mingyang, Song Yuhan, Chen Zhijie

Physicochemical Problems of Mineral Processing

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2024

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Vol. 60, iss. 1

art. no. 185553

EN

It’s highly challenging to separate feldspar from quartz by flotation owing to their similar crystal structure and physicochemical properties. Using mixed collectors has become a promising method to improve the quartz-feldspar separation. In this study, mixed dodecyl amine (DDA) and sodium petroleum sulfonate (SPS) surfactants were used in the flotation separation of feldspar and quartz, and the adsorption mechanism of mixed collectors and depression mechanisms of two depressants were investigated through zeta potential, contact angle and Fourier transform infrared (FT-IR) spectra. When the pH reached 4.5, the separation of feldspar from quartz was more obvious. In the presence of DDA/SPS collector, the contact angle of feldspar was increased more obviously leading to enhance hydrophobicity. The infrared spectra revealed the interaction of collectors on feldspar surface involved physical and chemical adsorption, whereas the adsorption of collector on quartz was only physical interactions. The use of sodium hexametaphosphate resulted in a significantly enhanced separation performance. The weaker physical adsorption of mixed collector on quartz can be destroyed by sodium hexametaphosphate. This study is beneficial for understanding the collect mechanisms of mixed cationic-anionic surfactants on quartz and feldspar minerals, and promotes the development of advanced feldspar separation techniques.

4

Mechanism of Ca2+/Fe3+-based synergistic activation of quartz

Liu Rongxiang, Yang Zhanfeng, Li Jie, Li Qiang, Wang Zhenjiang, Luo Xiaofeng

Physicochemical Problems of Mineral Processing

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2023

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Vol. 59, iss. 1

art. no. 162262

EN

Although the flotation behaviors of iron concentrate and quartz are significantly different, quartz is the primary factor that affects the quality of iron concentrate. The flotation mechanism of quartz in the presence of mixed cationic Ca2+/Fe3+-co-activated SDS catcher was studied by conducting flotation tests with pure quartz mineral. The solution chemical calculation method, zeta potential calculation method, Fourier transform infrared (FT-IR) spectroscopy technique, X-ray photoelectron spectroscopy (XPS) technique, and other techniques were used to conduct the studies. The results showed that the maximum Ca2+/Fe3+-based synergistic activation of the flotation recovery process could be achieved in a certain range of pH values when three different activators were added sequentially. Analysis of the zeta potential values revealed that the Ca2+/Fe3+-activated quartz surface improved the extent of positive electricity generated and enhanced the SDS adsorption ability of the quartz surface. Results obtained using the FT-IR technique revealed that Ca2+/Fe3+ exerted a synergistic effect, and the adsorption process exploited the single oxygen bond interactions in the monovalent hydroxyl complex Ca(OH)+ and the double oxygen bond interactions in the Fe(OH)3 precipitates. Results obtained using the XPS technique revealed that the synergistic effect exerted by Ca2+/Fe3+ was significantly stronger than that exerted by Ca2+ or Fe3+ alone. The stable Fe-based six-membered chelate ring was formed on the surface of quartz when Fe3+ was the activator, and the chain-like Ca-based complex was formed when Ca2+ was the activator. The adsorption process on the surface of quartz proceeded following chemical as well as physical adsorption pathways. The results revealed that Ca(OH)+ and Fe(OH)3 played prominent roles during the activation of quartz surfaces in the presence of Ca2+/Fe3+.

5

Counterion effects on the alkali dissolution mechanism of quartz

Yao Yu-yun, Tang Yun, Yang Yong, Li Guo-hui, Wu Bo, Dai Wen-zhi

Physicochemical Problems of Mineral Processing

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2023

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Vol. 59, iss. 1

art. no. 160038

EN

In gold ore, quartz plays an important role in mineral formation by acting as the follower. Understanding counterion release, transport, and deposition in alkali solution is a prerequisite for evaluating the potential role of gold separate from quartz deposits in pretreatment. In this work, the aggregation, retention, and release of counterion in alkali solution media were investigated by kinetic research and pure mineral experiments, the correlation and mechanism of these processes were revealed by combining geochemical theory, interaction energy calculation, and quantum chemistry. The results showed that the retention and release of counterion were closely related to the dissolution and corrosion rate of quartz. The NH4+ and Fe2+ with higher mineral affinity reduced the quartz stability, and the dispersion stability and mobility of the quartz were greatly improved by an alkaline substance due to the enhancement of steric hindrance effects. Quantum chemical calculation results show that ammonium ion promotes the dissolution of quartz stronger than ferrous ion, which is mainly reflected in reducing the activation energy required for the formation of transition state (TS1), which can be verified by kinetic calculation. These findings provide essential insight into the extraction of gold coated by quartz as well as a vital reference for the experiment of gold-loaded quartz leaching in mineral processing.

6

Activation of quartz flotation by Cu2+, Ni2+ in the sodium ethylxanthogenate (EX) system

Liu Yang, Tong Xiong, Xie Rui-Qi, Xie Xian, Song Qiang, Fan Pei-Qiang

Physicochemical Problems of Mineral Processing

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2023

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Vol. 59, iss. 2

art. no. 166368

EN

During the flotation of metal sulfide minerals, due to the interference of unavoidable ions, the quartz also partially floats in some cases. The studies on the mechanism of quartz being activated and floating up are still insufficient. In this study, the influence of the Cu2+ and Ni2+ unavoidable ions on the floatation of quartz was studied by micro-flotation experiments, adsorption detection, zeta potential measurement, solution composition calculation, infrared spectroscopy (FT-IR) and X-ray photoelectron spectroscopy (XPS) analyses, and atomic force microscopy (AFM) observation. This provides a theoretical reference for further understanding the mechanism of sodium ethylxanthogenate and quartz surface, as well as the development of a new quartz depressant. The results of flotation showed that after activation by Cu2+ (1×10-4 mol/dm3) and Ni2+ (5×10-5 mol/dm3), the quartz was captured by sodium ethylxanthogenate (EX: 1.4×10-4 mol/dm3) under alkaline conditions (pH=10), while the best recoveries were obtained as 80% and 43%, respectively. The results of adsorption and zeta potential measurements showed that the precipitation rate of Cu2+ was greater than that of Ni2+ under alkaline conditions. Additionally, both Cu2+ and Ni2+ electrostatically adsorbed on the quartz surface and changed the zeta potential of quartz. The solution composition calculation further showed that Cu(OH)+, Cu(OH)2(s), and Ni(OH)+, Ni(OH)2(s) were the main components in the solution under alkaline conditions. The FT-IR and XPS analyses and AFM observations demonstrated that Cu and Ni species adsorbed on O atoms on the quartz surface, providing active sites for EX adsorption, and EX combines with Cu and Ni species on the quartz surface to generate -O-Cu-EX and -O-Ni-EX complexes. Finally, the quartz floated up due to the formation of hydrophobic products and firm adsorption.

7

Characterization of Ijero-Ekiti Quartz as Refractory Raw Material for Industrial Furnace

Omidiji B. V., Ogundipe O. B., Owolabi H. A.

Archives of Foundry Engineering

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2023

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Vol. 23, iss. 4

14--21

EN

This study investigated the suitability of Ijero-Ekiti quartz as a refractory raw material for industrial furnace applications. In order to ascertain its prospective applications, the thermal behaviour, mineralogical composition and chemical composition were determined. Ijero-Ekiti quartz was characterized using Fourier Transform Infrared Spectroscopy (FTIR), X-ray Diffraction (XRD), Thermogravimetric and Differential Thermal analysis (TGA and DTA). Its thermal conductivity with specific heat coefficient was determined. The outcome revealed that the quartz sample has a high purity of 94.3% SiO2, making it suitable as a refractory material. The XRD analysis revealed the presence of alpha-quartz as the dominant crystal phase, which is desirable for refractory applications. The FTIR analysis indicated the absence of hydroxyl (-OH) groups. This indicates a low risk of failure and damage such as spalling, cracking and other forms of damage when produced into bricks. The TGA and DTA displayed significant mass losses and large endothermic bands, which were connected to the dehydroxylation of the quartz rock samples. Based on the demonstrated qualities, the quartz rock sample could be subjected to thermal processing. This study therefore established that Ijero-Ekiti quartz is a suitable raw material for refractory applications due to its high purity, alpha-quartz dominant crystal phase, absence of hydroxyl groups, and uniform morphology.

8

Numerical Investigation of the Propagation Characteristics of Surface Transverse Wave Considering Various Quartz Substrate and Electrode Configurations

Jiang Chao, Cao Xiaoli, Yang Feng, Liu Zejun

Archives of Acoustics

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2023

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Vol. 48, No. 3

403--412

EN

Featured with a higher velocity, increased power handling capability, and better aging behavior, surface transverse wave (STW) shows more promising prospects than Rayleigh wave nowadays in various sensing applications. The need to design, optimize, and fabricate the related devices motivates the development of modeling and simulation. For this reason, a three-dimensional (3D) finite element (FE) simulation of STW on quartz, considering the crystal cut angle and the electrode effects, is presented in this study. Firstly, we investigated the effects of quartz’s cut angle on the generated waves. Here, the polarized displacements were analyzed to distinguish the wave modes. Secondly, the investigations of the electrode effects on the polarized displacement, phase velocity, and electromechanical coupling factor (K2) were carried out, for which different material and thickness configurations for the electrodes were considered. Thirdly, to examine the excitation conditions of the generated waves, the admittance responses were inspected. The results showed that not only the crystal cut angle but also the density and the acoustic impedance of the interdigital transducer (IDT) material have a strong influence on the excited waves. This article is the first to analyze STWs considering quartz’s cut angle and electrode effect through a 3D FE model. It could provide a helpful and easy way to design, optimize, and fabricate the related surface acoustic wave devices.

9

Understanding the collection behavior of gangue minerals in fine flake graphite flotation

Xu Wenlu, Sun Kangkang, Qiu Yangshuai, Zhang Lingyan, Yang Luo, Wei Shaowei, Ding Dafa

Physicochemical Problems of Mineral Processing

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2022

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Vol. 58, iss. 1

101--112

EN

Flotation is one of the most common and effective methods for the beneficiation of natural graphite resources. However, the upgrading efficiency of flotation is always finite due to the undesirable collection of gangue minerals. In this work, the collecting mechanism of three typical gangue minerals, including mica, quartz, and feldspar, in fine flake graphite flotation was investigated. Results of batch flotation tests for single-minerals and artificial mixtures confirmed the enhanced collection of gangues in the presence of graphite particles. Contact angle and zeta potential results and theoretical calculations of the interaction between graphite and gangue particles based on typical DLVO theory indicated that it is impossible to collect gangue minerals by true flotation or through heterocoagulation with graphite particles. The fitting results of accumulated gangue recoveries and accumulated water recoveries using the Warren method demonstrated that most gangue minerals entered the concentrate through entrainment, with a small proportion by bubble inclusions.

10

The effect of shape and roughness on flotation and aggregation of quartz particles

Guven Onur

Physicochemical Problems of Mineral Processing

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2022

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Vol. 58, iss. 6

art. no. 154021

EN

A combination of grinding and abrasion processes was applied to control the shape and roughness of quartz particles to investigate their roles in flotation recoveries and aggregation rates at different collector concentrations. The results showed that while the roundness values (Ro) of quartz particles varied in the range of 0.56-0.58 (Ro) at 480 and 1920 sec grinding, the roughness values of particles varied between 3.12-4.02 μm at 60 and 240 min abrasion. The flotation and aggregation tests showed while the flotation recovery increased from 31.3 % to 34.2 % in reverse proportion to their roundness values at 1x10-6 M DAH concentrations, a similar increasing trend from 34.1% to 38.1 % as a function of their roughness value from 3.12 μm to 4.02 μm. On the other hand, in the case of aggregation tests, while the turbidity values decreased from 40.6 NTU to 32.1 NTU at 1x10-6 M DAH concentrations for rounder particles, it was found as 36.2 NTU to 31.8 NTU for rougher ones. The overall results of this study indicated that tuning the morphology of quartz particles may be used to adjust both the flotation and aggregation rate of particles.

11

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.

12

Experimental study on the effect of ions on the surface hydration characteristics of fine quartz

Liu Chunfu, Min Fanfei, Liu Lingyun, Chen Jun, Ren Bao, Lv Kai, Tan Yujiao

Physicochemical Problems of Mineral Processing

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2022

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Vol. 58, iss. 4

art. no. 150280

EN

The fine quartz particle hydration and effects of metal ions on the hydration characteristics of fine quartz surface are investigated using the rheological experiment. Several important factors affecting hydration factors, such as particle sphericity, solution pH, ion species, ion concentration were investigated. The results show that viscosity and hydration factor of fine quartz suspension increase with the increase of solution pH. wherein quartz particles have more negative charges on the surface in alkaline environment and strong hydration repulsion; The introduction of metal ions enhances the hydration strength of fine quartz surface to a certain extent. In contrast, high valence and high concentration will increase the viscosity of fine quartz suspension, and the hydration factors of particle surface also increase. At the same ion concentration, the order of influence on the hydration factors of fine quartz particles is Mg2+ > Ca2+ > Na+ > K+. This finding has been attributed to the combination of metal ion hydration and its adsorption on the mineral surface. This study will provide the theoretical guiding significance for the refractory coal slime water and other mineral processing wastewater containing quartz particles.

13

Effect of Na+, Ca2+ on the hydration properties of quartz surface: a molecular dynamics simulation study

Liu Chunfu, Min Fan-fei, Chen Jun, Liu Ling-yun, Ren Bao, Lv Kai

Physicochemical Problems of Mineral Processing

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2022

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Vol. 58, iss. 3

art. no. 147452

EN

Effects of metal ions on the surface hydration of fine quartz are investigated by the theoretical methodologies. The hydration layer on the quartz surface is made up of three layers of water molecules, about 8-10 Å. The interaction energy of ions changes from -1.071 eV in water to -1.821 eV (Na+) and -1.896 eV (Ca2+) when ions are present. Metal ions improve the interaction of water molecules with the quartz surface, allowing more water molecules to enter the second and third hydration layers. In the presence of Na+, the diffusivity of water molecules is greater than in Ca2+ solutions. Increased interaction between water molecules and surfaces in the order Ca2+ > Na+ is consistent with metal ions’ propensity to hydrate.

14

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.

15

The internal dose rate in quartz grains: experimental data and consequences for luminescence dating

Szymak Agnieszka, Moska Piotr, Poręba Grzegorz, Tudyka Konrad, Adamiec Grzegorz

Geochronometria

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2022

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Vol. 49, no. 1

9--17

EN

This work considers the impact of the internal alpha and beta dose rates in quartz grains obtained from sandy sediments on the results of luminescence dating. The internal dose rates reported here (ca. 0.01–0.21 Gy · ka−1) play a particularly important role, because of low (ca. 0.8–0.9 Gy · ka−1) or very low (ca. 0.4–0.6 Gy · ka−1) external dose rates. In these cases, the internal dose rates form a significant fraction of the total dose rates, often exceeding 10%. Ignoring this contribution would have made the considered luminescence ages artificially older. In our study, we measure both the internal alpha and beta contributions as the latter is usually neglected in the case of quartz. The dose rate measurements were performed using the innovative μDose system.

16

Evaluating the effect of hydrofluoric acid etching on quartz grains using microscope image analysis, laser diffraction and weight loss particle size estimate

Poręba Grzegorz, Tudyka Konrad, Szymak Agnieszka, Pluta Julia, Rocznik Joanna, Świątkowski Jakub, Osadnik Rafał, Moska Piotr

Geochronometria

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2022

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Vol. 49, no. 1

1--8

EN

In this work we investigate the quartz etching process using hydrofluoric acid for trapped charge dating (TCD) applications. It is done using material collected from an active sand mine in Bełchatów Nowy Świat, central Poland. Approximately 20 kg of material was collected and prepared using routine procedures that are applied in TCD laboratories. The material was sieved using 180–200 μm meshes, and the selected fraction was etched for various time intervals. Sieved samples were etched for durations from 0 min up to 180 min and measured with microscope image analysis (IA), laser diffraction (LD), and mass loss which were used to estimate the depths of etching. Our results show statistical data on how non-uniform the etching process is. We estimate this as a function of etching time from IA, LD and mass loss. In our investigation, mass loss measurements with the assumption of spherical grains correspond to the decrease of radius of ca. 0.151 ± 0.003 μm ˑ min–1. In case of LD, a rough etch depth estimation corresponds to a range 0.06–0.18 μm ˑ min–1 with median at 0.13 μm ˑ min–1. Microscope IA gives a 0.03–0.09 μm ˑ min–1 with a median at 0.05 μm ˑ min–1. Moreover, quartz grains are fractured into smaller pieces while etching. It means that assumptions that are used in etch depth estimation from mass loss are not correct. They incorrect not only because grains are not spheres but also because the number of grains is not constant. Therefore, the etch depth estimated from mass loss might be overestimated. Using microscope IA we report etch depth ranges that might be used to roughly estimate the etch depth uncertainty.

17

Zagrożenia frakcją respirabilną krystalicznej krzemionki w przemysłowych procesach wysokotemperaturowych

Surgiewicz Jolanta, Pośniak Małgorzata

Podstawy i Metody Oceny Środowiska Pracy

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2021

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Nr 3 (109)

189--204

PL

W artykule przedstawiono wyniki badań dotyczące rozpoznania wielkości narażenia na krystaliczną krzemionkę występującą we frakcji respirabilnej w powietrzu na stanowiskach pracy w procesach odlewniczych. Badaniami objęto dziesięć stanowisk pracy w dwóch zakładach przemysłowych. Próbki powietrza pobierano za pomocą cyklonów umożliwiających pobranie z powietrza frakcji respirabilnej aerozolu. Krystaliczną krzemionkę oznaczano w powietrzu metodą spektrometrii w podczerwieni z transformacją Fouriera (FT-IR). Na badanych stanowiskach stwierdzono stężenia frakcji respirabilnej krzemionki przekraczające wartość normatywu higienicznego (NDS) wynoszącego w Polsce 0,1 mg/m3. Największe stężenia: 0,25 i 0,15 mg/m³ oznaczono w procesach przygotowania mas formierskich na stanowisku przerabiacza mas i czyszczenia form do odlewu oraz na stanowisku formierza maszynowego, jak również na stanowisku kadziowego pracującego przy przygotowaniu i obsłudze kadzi – 0,13 mg/m³. Stężenie frakcji respirabilnej w aerozolu krystalicznej krzemionki zależy od prowadzonego procesu z udziałem niezwiązanego piasku krzemowego i rodzaju wykonywanych czynności, w których powstaje duża ilość respirabilnego aerozolu, a także od natężenia prac wykonywanych na badanym stanowisku. Dla większości badanych stanowisk stwierdzono zagrożenie krystaliczną krzemionką na stanowiskach pracy. Wyniki badań wskazują na konieczność podjęcia środków zaradczych w celu eliminacji tego zagrożenia. Zakres tematyczny artykułu obejmuje zagadnienia zdrowia oraz bezpieczeństwa i higieny środowiska pracy będące przedmiotem badań z zakresu nauk o zdrowiu oraz inżynierii środowiska.

EN

The article presents results of research on recognition of a size of crystalline silica exposure present in respirable fraction in the workplace air at high-temperature foundry processes. The study included 10 workplaces in two factories. Air samples collected with cyclones allowing the separation of respirable air. The crystalline silica was measured in air with Fourier transform infrared spectrometry (FT-IR). High concentrations of respirable fraction of silica, exceeding the value of the hygienic standard (NDS) of 0.1 mg/m3 in Poland, were found at the studied workplaces. The largest concentration of respirable crystalline silica (0.25 mg/m³ ) was found in the processes of sand preparation of transformer masses and processes of preparing forms on a position of aformer machine – 0.15 mg/m³ and on position of a sliding and pourer forms, at astand of machine moulder, at a stand of ladle maker during preparation and operation of ladles – 0.13 mg/m³ . The amount of respirable aerosol coagulation crystalline silica in high-temperature processes depends on a type of process and is especially present in stages involving unbound silica sand. It also differs in workflow steps and intensity performed on particular workplaces, where large amount of respirable aerosol is produced. Majority of examined workplaces are exposed to high risk of occurring crystalline silica in the respirable fraction. Research results indicate the need of implementing remedial measures to eliminate the hazard. This article discusses the problems of occupational safety and health, which are covered by health sciences and environmental engineering.

18

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.

19

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.

20

Citric acid inhibits the floatability of quartz in the Mg2+ system

Wang Yonglun, Li Jie, Zhang Wenhao, Li Pengwei, Guo Jing, Yao Kai

Physicochemical Problems of Mineral Processing

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2021

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Vol. 57, iss. 6

1--11

EN

Citric acid is a small-molecule organic acid, which can be used as an inhibitor for the flotation of Mg2+ activated quartz. Methods such as flotation experiments, zeta potential, FTIR qualitative and quantitative calculations, and solution chemistry calculations were used in this study to conduct systematic research to study activation and inhibition mechanisms. The results show that adding only a quarter of citric acid under the optimal conditions of Mg2+ activated quartz produces the best inhibitory effect. Mg2+ and citric acid affect the zeta potential of the quartz surface in the zeta potential experiment. FTIR qualitatively found that under the action of Mg2+, sodium oleate was adsorbed on the quartz surface in the form of physical adsorption; quantitative analysis clearly explained that after the chemical reaction between citric acid and Mg2+, it desorbed from the quartz surface into the water system. According to the chemical calculation of the solution during the flotation process, it is found that the reaction product of citric acid and Mg2+ has no inhibitory effect; only the amount of Mg2+ is consumed, thereby reducing the number of activating factors and cutting off the medium of sodium oleate adsorbed on the surface of the quartz.