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1

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.

2

Effectiveness of using physical pretreatment of lignocellulosic biomass

Piątek Milena, Bartkowiak Anna

Journal of Water and Land Development

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2023

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no. 58

62--69

EN

Pretreatment is aimed at making lignin structures, which in turn causes decrystallisation and depolymerisation of cellulose. This treatment allows to increase the energy potential of substrates. A properly selected method allows for obtaining larger amounts of biogas with a high content of biomethane. The aim of the study was to analyse selected pretreatment methods (ultrasonic and hydrothermal) for biogas yield, including biomethane, and to demonstrate the effectiveness of obtaining additional electricity and heat from these methods. It was based on the literature data. On basis the study, the following information was obtained: average yield of biogas and biomethane before and after treatment, difference in yield of biogas and biomethane after treatment, and the effect of treatment on the substrate used. Moreover, an estimate was made of the effectiveness of obtaining additional electricity and heat from selected pretreatment methods compared to hard coal. Based on the analysis of the ultrasonic treatment analysis, it was shown that the best result was obtained with the ultrasound treatment of the mixture of wheat straw and cattle manure with the following parameters: frequency 24 kHz, temperature 44.30°C, time 21.23 s. This allowed a 49% increase in biogas production. The use of pretreatment would therefore allow the production of more electricity and heat capable of replacing conventional heat sources such as coal.

3

Strengthening the rough selection effect of n-ethyl o-isopropyl thionocarbamate (Dow: Z-200) on chalcopyrite by ultrasonic pretreatment

Wang Yan, Wang Yubin, Yu Bo, Wang Xin, Ma Xiaoxiao

Physicochemical Problems of Mineral Processing

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2021

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Vol. 57, iss. 1

64--74

EN

In this study, the properties of (CH3)2CHOC(S)NHC2H5(Dow: Z-200) after the ultrasonic pretreatment was characterized by employing surface tension, viscosity, and Fourier transform infrared (FTIR) spectroscopy, and its influence on chalcopyrite rough selecting was investigated. The results indicate that the pretreated Z-200 can improve the index of chalcopyrite roughing. And, under the same reagent system, the recovery of copper reached 82.84% which was an increase of 24.44% compared with the untreated when Z-200 after ultrasonic pretreatment was applied to the rough separation of chalcopyrite. The reason why ultrasonic can strengthen the flotation effect of Z-200 on chalcopyrite is that ultrasonic pretreatment can decrease the surface tension and viscosity of Z-200 and enhance its foaming performance. Meanwhile, the ultrasonic cavitation destroys the molecular structure of Z-200, so that the relative proportion of methyl absorption peak and amine absorption peak in Z-200 increases. This also further improves the collection performance and foaming performance of Z-200 and strengthens its separation effect on chalcopyrite. The research provides a new idea for Z-200 to act on chalcopyrite and improve its flotation efficiency, reduce the amount of flotation reagent, and its pollution to the environment. It also provides a theoretical basis for expanding the application of ultrasonic technology in the field of flotation.

4

Effects of ultrasonic pretreatment on the flotation behavior of galena with and without the presence of pyrite

Lu Dongfang, Chen Lanlan, Ma Yongyi, Zheng Xiayu, Wang Yuhua

Physicochemical Problems of Mineral Processing

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2020

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Vol. 56, iss. 4

611--624

EN

Utilizing the ultrasonic pretreatment, flotation tests, ICP-OES, and XPS analysis, the effect of the different ultrasonic pretreatment methods on the flotation behavior of galena were investigated. The flotation recovery of galena was improved for pretreated single galena sample, which is mainly attributed to the efficient removal of the oxidized components and contaminants on the surface of galena by the acoustic cavitation. However, the flotation recovery of galena was decreased when pretreated mixture sample of galena and pyrite was used. Inductively Coupled Plasma Optical Emission Spectrometer (ICP-OES) and X-ray photoelectron spectroscopy (XPS) results reveal that ultrasonic pretreatment facilitates the conversion of PbS to Pb(OH)2 and PbSO4. Besides, the flotation recovery of galena was affected to varying degrees when the galena was mixed with the pyrite of the different particle sizes in the ultrasonic pretreatment process. The reason is that the change in the surface area ratio of these two minerals affects the electrochemical reaction rate between galena and pyrite.

5

Effect of ultrasonic pre-treatment on coal slime flotation

Lv Wenbao, Chen Jun, Min Fanfei, Hou Baohong, Liu Chunfu

Physicochemical Problems of Mineral Processing

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2020

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Vol. 56, iss. 1

173--183

EN

Combined with the characteristics of flotation feed originating from China’s Panyidong Coal Preparation Plant, the ash, zeta potential, X-ray fluorescence spectroscopy and contact angle test were used to study changes in the surface properties of flotation feed under ultrasonic pre-treatment, and its effect on flotation of coal slime. Results show that Preferred pre-treatment process is ultrasonic secondary treatment, ultrasonic secondary pre-treatment can remove most of the high-ash fine mud for instance kaolinite, montmorillonite and quartz in the coal slurry, reduce the surface electronegativity of coal particles, and increase the contact angle of coal particles. Thus, the concentrate ash content decreases to 13%, the recovery rate, yield of flotation concentrate and combustible matter recovery reach 92.6%, 90.9% and 97.6%, respectively.

6

The Preparation of Soluble Cellouronic Acid Sodium Salt by 4-Acetamide-TEMPO Mediated Oxidation of Ultrasound-Pretreated Parenchyma Cellulose from Bagasse Pith

Gao X., Chen K., Zhang H., Peng L.

Archives of Acoustics

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2014

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Vol. 39, No. 2

267--275

EN

The parenchyma cellulose isolated from bagasse pith was used as an alternative resource for preparation of water-soluble cellouronic acid sodium salt (CAS). The influence of ultrasound treatment on the cellulose was investigated for obtaining CAS by regioselective oxidization using 4-acetamide-TEMPO and NaClO with NaClO2 as a primary oxidant in an aqueous buffer at pH 6.0. The yield, carboxylate content and polymerization degree (DP) of CAS were measured as a function of ultrasonic power, agitating time and cellulose consistency by an orthogonal test. The ultrasound-treated conditions were further improved by discussion of ultrasonic power, the most important factor influencing the yield and DP. An optimized CAS yield of 72.9% with DP value (DPv) of 212 was found when the ultrasonic strength is 550 W, agitating time is 3 h and cellulose consistency is 2.0%. The oxidation reactivity of cellulose was improved by ultrasonic irradiation, whereas no significant changes in crystallinity of cellulose were measured after ultrasonic treatment. Moreover, the ultrasound treatment has a greater effect on yielding CAS from parenchyma cellulose than from bagasse fibrous’ one. The CAS was further characterized by Fourier transform infrared spectroscopy (FT-IR) and Scanning electron microscopy (SEM).

7

Enhancement of colemanite flotation by ultrasonic pre-treatment

Ozkan S. G., Gungoren C.

Physicochemical Problems of Mineral Processing

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2012

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Vol. 48, iss. 2

455-462

EN

Ultrasonic treatment methods are widely used for surface cleaning purposes prior to application of flotation. In this study, enhancement possibility for colemanite recovery was investigated with use of an ultrasonic bath prior to flotation. Representative colemanite ore samples from Hisarcik and Espey open pit mines, located in Emet, Turkey were used for this purpose. Ultrasonic flotation experiments were carried out by using circularly shaped RK-106 model of ultrasonic bath with constant frequency and power, manufactured by Bandelin GmbH in Germany and Denver Sub-2A type flotation machine with an impeller speed of 1200 rpm and 1 cubic decimeter capacity. The reagent for colemanite flotation was Cytec-R825 with variable dosages during conventional and ultrasonic flotation experiments. The results showed that ultrasonic pre-treatment helps desliming and hence yields more borate recovery in floated part with lower borate content in tailing than under conventional flotation conditions by using similar reagent dosages.

8

Wpływ dezintegracji ultradźwiękowej osadów ściekowych na przebieg procesu stabilizacji beztlenowej

Bień J. B., Szparkowska I.

Inżynieria i Ochrona Środowiska

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2004

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T. 7, nr 3/4

341-352

PL

W układach technologicznych realizujących proces oczyszczania ścieków powstają znaczne ilości osadów nadmiernych charakteryzujących się słabą podatnością na biochemiczny rozkład w warunkach beztlenowych. Podatność substancji organicznej zawartej w osadzie na biodegradację zwiększa się ze wzrostem stopnia upłynnienia osadu oraz wzrostem rozdrobnienia cząstek fazy stałej. Kondycjonowanie osadów ściekowych polem ultradźwiękowym przed procesem stabilizacji beztlenowej może być istotnym czynnikiem dezintegrującym. Efektem skutecznej dezintegracji jest intensyfikacja procesu fazy kwaśnej fermentacji, wyrażająca się zwiększeniem stężenia i szybkości przyrostu lotnych kwasów tłuszczowych (LKT), powodując w rezultacie wzrost wydajności produkcji biogazu. Przeprowadzono proces mezofilowej fermentacji metanowej osadu nadmiernego niekondycjonowanego oraz poddanego czynnemu działaniu pola ultradźwiękowego. Jako kryterium oceny zmian wywołanych czynnym działaniem pola ultradźwiękowego przyjęto intensywność wydzielającego się biogazu. Podczas procesu wykonywano następujące oznaczenia fizyczno-chemiczne osadów: lotne kwasy tłuszczowe, sucha masa, sucha masa mineralna, sucha masa organiczna, pH oraz zasadowość.

EN

The aim of the study was the analysis of the influence of the ultrasonic disintegration on the efficiency of the anaerobic stabilization process. The process was conducted in the closed sludge digester, made in a form of glass cylinder of the active capacity of 5 dm3, equipped with the installation maintaining constant temperature of the process (35°C), the device providing appropriate rate of mixing (120 r.p.m.) and the installation serving to diminish the biogas. The process of periodical digestion lasted for 28 days. The organic matter present in the excessive sludge is difficult to biodegradation. The basic part of it are living microorganisms, which are not substrate, they can alone participate in the process of conversion of the matter but not going under the biodegradation. During the 28-days period of digestion they leave the digester in an active state. Therefore in order to intensificate the hydrolysis phase, the excessive sludge was ultrasonic pretreated before the anaerobic digestion process. The ultrasound amplitude was varied within the range from 8 to 16 µm. The impact of different amplitude and time of pretreatment on the extent of the disintegration was examined. The efficiency of the pretreatment, the direct result of which is disintegration of the sludge, was evaluated on the basis of the chemical oxygen demand (COD). The anaerobic digestion of excessive sludge following ultrasonic pretreatment was significantly intensified. Volatile fatty acids, dry mass, organic mass and mineral mass, pH, alkalinity were the main parameters studied during the anaerobic stabilization process. There was noticed the increase in the volatile solids reduction as well as the increase in the biogas production. The intensity of the biogas release plays in this connexion an important role in the control of conversion undergoing during the process.