The mineral composition of milk and whey is analyzed. The significance of the main macroelements (calcium, phosphor, magnesium) and microelements for vital functions of the organism is noted. The importance of the balanced proportion of calcium and phosphor ions in nutrition is emphasized; the ratio of these elements in the protein–mineral concentrate is noted. The conditions and possible mechanisms, which influence the formation of protein concentrates, are analyzed on the basis of the experimental data related to the pH variation, the quantity of the recovered protein, and Ca:P ratio for various current densities. The determination of mechanisms of protein–mineral concentrate formation is important for preparation of end products, including those with the specified mineral composition.