Electrochemical machining (ECM) as process of applied electrochemistry is metal anodic dissolution at high current densities (up to 100 A/cm²) and high rates of electrolyte flow through small interelectrode gap (IEG) (less than 1 mm) for the purpose of heat and reaction products removal from the treatment area. Considering particular ECM conditions (constant removal of surface layers owing to their thermokinetic instability), for ECM application simple electrolytes are used as a rule. The chloride-nitrate solutions have received most common application for ECM of gas-turbine engine blades from refractory brightrays. However composition and properties of such electrolytes vary in the course of their long-term maintenance owing to accumulation of electrode reaction products.    The aim of present work is to investigate the dynamics of composition and properties of chloride-nitrate electrolyte changes under the conditions of Ni-Cr alloys (~15% Cr) anodic dissolution at high current densities during electrolyte long-term exploitation (up to 10 A·hour/l), as well as to determine the impact of these changes on the electrochemical machining rate and electrolyte localizing power. The final aim of this investigation was the development of methods of electrolyte purification and stabilization of it composition and properties during long-term service.  It is established, that nitrate- and chloride-ions concentration does not vary in the indicated band of exploitation period, however, owing to solution рН variation (from 6.5 in initial period of machining to ~ 8,8) the electrolytic conductivity varies inappreciably but then retains near stationary value. The qualitative modification of solution composition (of liquid phase) happens only owing to bichromate-ion accumulation as the result of anodic dissolution of chromium, which is alloy component. However, no more than 25 % of all dissolved chromium turns into soluble form in electrolyte as the sequence of: a) the partial dissolution of chrome in the form of Cr (III) with the subsequent precipitation in the form of hydroxide in solid phase; b) bichromate-ion adsorption on the deposit composed of the mixture of nickel and chromium hydroxides. After 10 A·hour/l the above-stated phase makes approximately third of all volume of a forecastle of the rig.   Solid products of machining, adsorbing on their  surface anodic dissolution products in ionic form, serves as the original natural adsorbent partially refining electrolyte from dissolved products of ECM (in particular, bichromates-ions). Thereof after ~ 2 A·hour/l bichromate-ion concentration in solution varies a little, and practically all products of alloy machining concentrate in the solid phase, as in the form of hydroxides, and with soluble products (bichromates-ions) adsorbed on it.   It is shown, that the alloy dissolution rate (in g/A·hour) practically does not vary in the course of machining in the indicated range of electrolyte exploitation and corresponds to chromium dissolution in the form of Cr (VI) and Cr (III). In the same time at the conditions of machining of the same alloys in chloride electrolyte  chromium dissolution proceeds only in the form of Cr (III) up to 100 A/cm².  The received outcomes have formed the basis of guidelines on development of the preparation and storing of electrolyte station for ECM of turbine engine blades from refractory brightrays.  These results also are necessary for determination of optimal pulse ECM parameters within micro-and a nanosecond band for the purpose of improvement of machining process localization.