The method of nickel and copper separation in the processing of wastewater containing nickel and copper trace elements has been developed and investigated. The method provides collective foam flotation extraction of nickel and copper by naphthenic acid solution in kerosene with subsequent selective re-extraction of nickel from the obtained organic phase of the foam product. The optimum conditions for selective re-extraction were determined: temperature 70 °C and pH = 375-425 Under these conditions the partition coefficient of nickel and copper reaches 140-145, which makes it possible to obtain after crystallization commercial nickel sulfate corresponding to the copper content in grade Ch of GOST 4465-74.
The basic technological scheme for producing pure nickel sulfate (nickel sulfate of higher grades) from wastewater of the Severonickel Combine developed and tested on a single technological sample is described. The effluents of the combine can be characterized as relatively poor solutions suitable for obtaining nickel in the form of commercial products - seven-water nickel sulfate. The proposed technology includes the following main operations: oxidative hydrolysis for purification from Fe, AI, etc.; purification from Co; froth flotation extraction; control flotation; operations on separation of aqueous and organic phases; reextraction of nickel; regeneration of the extractant and crystallization of nickel sulfate. The obtained nickel sulfate meets GOST requirements for nickel sulfate of higher grades. The pre-feasibility study showed that the water treatment process is costless due to profit from sales of the resulting commercial products.
Nowadays, it is difficult to imagine science existing without any connection with experiment. The very notion of experiment has undergone significant changes in the last decades, Earlier the essence of experiment was reduced to the study of well-organized systems. However, in our time the tendency has developed to move from the study of well-organized systems to poorly organized, diffuse systems or to the study of problems of so-called bad structure. Two significantly different approaches to the study of poorly organized systems can be pointed out, which have clearly emerged over the last ten decades. The first approach consists in the use of ideas and methods of multivariate mathematical statistics, the second is a purely logical analysis of their control process. Here we are already dealing with the cybernetic approach. At present, the problem of studying poorly organized systems acquires paramount importance in view of the fact that the majority of real systems belong exactly to this category of systems. Moreover, we can confidently say that the methodology of one-factor experiment does not meet in the vast majority of cases the modern real goals and objectives of the experiment. When studying such systems, it is often necessary to operate with a combination of both cybernetic and statistical approaches in order to obtain the most complete understanding of the essence and nature of the process or system under study.
