Abstract
This paper describes, at first, a bilinear (nonlinear) system in mineral processing. The authors have showed two examples of the bilinear system, one is that of flotation and the other of ore-grinding process. The obtained bilinear concentration regulation system is based on back-mixing model. Then, the authors have studied dynamical characteristics of the bilinear system as a control object. The results are as follows: 1. Nonlinearity (a) In the case of small variance of manipulated variable, the plant can be linearized, but the process gain and the mean residence time depend on equilibrium points. (b) In the case of stepwise change of manipulated variable, the process gain and the mean residence time depend on manipulated variable.