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The effect of microbubbles on coarse particle anionic flotation: analysis and optimization

Abbaker Ahmed, Aslan Nevzat

Physicochemical Problems of Mineral Processing

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2023

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Vol. 59, iss. 6

art. no. 172298

EN

Since the grinding and chemical reagents required for flotation are expensive, coarse particle flotation reduces grinding costs and makes the subsequent process more accessible and cheaper. Recent studies suggest that the flotation of coarse particles using microbubbles has some advantages. However, a thorough analysis of the effectiveness of various flotation parameters and the impact of their interactions on the recovery of coarse particles in the presence and absence of microbubbles has yet to be fully understood. In the current study, the two-level factorial and Box-Behnken experimental designs were performed to characterize, assess, and optimize the implications of seven numerical (sodium oleate, collector; calcium oxide, activator; MIBC, frother; impeller speed; froth depth; pulp concentration; fine particles) and one categorical (microbubbles) independent parameters on the coarse quartz particles. Characterization revealed that froth depth did not significantly affect the flotation recovery of coarse particles in the mechanical laboratory cell. The effects of the variables in the presence of microbubbles revealed that sodium oleate and impeller speed significantly impacted recovery, followed by calcium oxide and fine particles, both of which had a medium influence, and MIBC and pulp concentration, which had a minimal impact. The recovery of coarse particles increased by 92.714% when microbubbles were used, compared to the estimated maximum recovery under ideal conditions of 62.258% without them. From this, it can be concluded that a high coarse particle flotation recovery is possible by optimizing the hydrodynamic conditions and the chemical environment using microbubbles.

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Acoustic Estimation of Resonance Frequency and Sonodestruction of SonoVue Microbubbles

Jurkonis R., Lamanauskas N., Šatkauskas S.

Archives of Acoustics

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2015

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Vol. 40, No. 3

293--300

EN

Acoustic properties of ultrasound (US) contrast agent microbubbles (MB) highly influence sonoporation efficiency and intracellular drug and gene delivery. In this study we propose an acoustic method to monitor passive and excited MBs in a real time. MB monitoring system consisted of two separate transducers. The first transducer delivered over an interval of 1 s US pulses (1 MHz, 1% duty cycle, 100 Hz repetition frequency) with stepwise increased peak negative pressure (PNP), while the second one continuously monitored acoustic response of SonoVue MBs. Pulse echo signals were processed according to the substitution method to calculate attenuation coefficient spectra and loss of amplitude. During US exposure at 50–100 kPa PNP we observed a temporal increase in loss of amplitude which coincided with the US delivery. Transient increase in loss of amplitude vanished at higher PNP values. At higher PNP values loss of amplitude decreased during the US exposure indicating MB sonodestruction. Analysis of transient attenuation spectra revealed that attenuation coefficient was maximal at 1.5 MHz frequency which is consistent with resonance frequency of SonoVue MB. The method allows evaluation of the of resonance frequency of MB, onset and kinetics of MB sonodestruction.

3

Development of immersed machine tool and machining in the strong alkaline water for reduction of CO2

Da Cruz J. R., Tanabe I., Sakaguchi N

Journal of Machine Engineering

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2014

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Vol. 14, No. 3

71--82

EN

Nowadays, eco-friendly manufacture has become common request in the manufacturing and production. The excessive electric power associated with the usage of large amount of oil for cooling and lubrication during machining can increase the CO2 emission which is considered as large problem for environment. On the other hand, the presence of the unwanted vibration during machine can affect the quality of production. The influence of immersed machine tool in strong alkaline water has been investigated in previous work for normal machine operation when no vibration occurred. In present research, the influence of immersed condition to the vibration of the bench lathe machine was investigated. Thermal deformations of the spindle when operating bench lathe coincide with machine resonances were also measured for evaluation of accuracy. The calculation of CO2 emission using immersed bench lathe machine was done by comparing with the conventional machining. It is concluded from the results that; (1) Excellent cooling efficiency can be achieved by using strong alkaline water added with microbubble, (2) Vibration of machine tool was reduced during immersed condition, (3) Thermal deformation of the bench lathe was very small despite no-forced cooling was used, (4) The large number of CO2 that released annually can be reduced by immersed of machine tool.