How can a time-varying process have a rate constant? Complete nonsense!

If I ask you: "What is the cars  rate constant?"

You will answer me: "I do not drive at a constant speed. I accelerate and brake. I determine the speed by the speedometer."

The flotation rate varies over time (see figure).

Why Russian scientists do not determine the flotation rate, how  I do it.

Why do they calculate the fictional "The flotation rate constant",  which does not exist? How can a time-varying process have a rate constant?

 Complete nonsense!

Ph.D. Natalia Petrovskaya

"National Research Technological University" MISIS (Moscow Institute of Steel and Alloys), (SUPPORTED BY RUSSIAN SCIENTIFIC FOUNDATION) wrote: "Investigations by the foam flotation method have established the relationship between the Beloglazov flotation rate constant and the qualitatively-quantitative composition of the components in the combination of collectors. When using a combination of butyl xanthate and TC in a 1: 2 ratio, the flotation rate constant... " More

 Filippov L.O.  (Université de Lorraine, France; National University of Science and Technology MISIS, Russia), Matinin A. S., Lekhatinov C. A. "Increasing the flotation kinetics in the multizone flotation machine of a reactor-separator type, under the  influence of pulser impact in the  running mode" More

Abramov A.A. (Moscow State Mining University) "Flotation enrichment methods" basic textbook for students. 

Kozin V.Z. *Ural State Mining University, Ekaterinburg, Russia.) "Critical review to the article "Determination of average flotation rate constants on the results of testing.