Thursday 21 November 2019

Why do scientists contradict themselves and the theory of flotation?

V.I. Melik-Gaykazyan, D.V. Dolzhenkov, N.P. Emelyanova, M.I. Trufanov, T.I. Yushina (Moscow Mining Institute, National University of Science and Technology «MISiS», Russia) wrote an article "NANOBUBBLES AND THE MECHANISM OF THEIR PHENOMENAL FLOTACTIVITY AND SELECTIVITY OF ACTION"- They took photos. The photographs show that the contact angle don't depends on the size of the bubbles. This is consistent with flotation theory.

They are aware of this and demonstrate a classic drawing on page 19 [2].
Why did a scientist draw dubious conclusions that contradict the theory of flotation?

They wrote in their article: "1. The reason for the high flotation activity of nanobubbles is their ability to instantly spread over the surface of the particles due to the high capillary pressure in them.
 2.  On the perimeter of the spreading nanobubble, transport” bubbles formed as a result of coalescence of microbubbles can easily be fixed. They float particles."

I answered: "I think they made false conclusions.
1. Bubbles stick to the HYDROPHOBIC SURFACE and in accordance with the 2nd law of thermodynamics.  
Probability of meeting the nanobubble and particles are very small, therefore, the effect of nanobubbles on flotation by this interaction mechanism is negligible (the nanobubble has an insignificant kinetic energy).

2. Coalescence of nanobubbles with each other is an unlikely thermodynamic process."

Ph.D. Natalia Petrovskaya

References
1. http://www.giab-online.ru/files/Data/2014/09/09_52-61_Melik-Gaykazyan.pdf
2. https://books.google.cl/books?id=ckw3DwAAQBAJ&pg=PA153&lpg=PA153&dq=%D0%BC%D0%B8%D0%BA%D1%80%D0%BE+%D0%BF%D1%83%D0%B7%D1%8B%D1%80%D1%8C%D0%BA%D0%B8+%D0%BC%D0%B5%D0%BB%D0%B8%D0%BA+%D0%B3%D0%B0%D0%B9%D0%BA%D0%B0%D0%B7%D1%8F%D0%BD&source=bl&ots=8vpIgYXPCh&sig=ACfU3U1FdRm2aW7o4NwbWVRCC9eT_K1DgA&hl=en&sa=X&ved=2ahUKEwih_O3rzfzlAhUCFbkGHRo0Bt4Q6AEwDHoECAoQAQ#v=onepage&q&f=false

No comments:

Post a Comment