Ural Federal University named after the first President of Russia B. N. Yeltsin, Ekaterinburg, Russia:

S. S. Naboychenko, Head of a Chair of Metallurgy of Heavy Non-Ferrous Metals, phone: +7 (343) 375-48-93

Influence of representative group of ionic and non-ionic surface-active substances on copper pressure precipitation parameters (process rate, produced powder properties, copper deposit value on inner reactor surface) was investigated at the temperature of 135–160⁰ C (1.5–3.0 MPa) from sulfuric acid solutions, contained 40–80 g/dm³ of Cu. Using carboxyl-containing water-soluble polymers, kinetic parameters arenot changed, powder deposits are less than 2–5% of powder mass, and changing of fineness and particle shape provides variation of specific area (0.05–0.18 m²/g), bulk weight (0.9–2.9 g/cm²), particle size (20–42 μm) and flowability (0–2.6 g/s). Consumption of surface-active substance above 0.003–0.007 g/g of Cu leads to increasing of carbon content in powder due to destruction of added organic reagents, especially with solution acidity and temperature increment. Anti-coating effect of surface-active substance was explained in terms of “sorption” mechanism in accordance with carboxyl groups of polymers form stable links with Cu(I) and Cu(II) ions. Due to the micelle nature of polyelectrolyte solutions, centers with increased copper ions (II) concentration are originated in solution. In these points, Cu(II) is firstly reduced to Cu(I), because this process rate is proportional to Cu(II) concentration. With limit equilibrium concentration of Cu(I), they are desorbed in solution with subsequent disproportionation and copper microparticles' formation. In addition, polymer active group regeneration is carried out together with further repeated process evaluation. COOH groups act as catalyst of metal phase nucleation stage with its displacement into solution. Surface-active substance additions make an influence on copper nucleus growth rate in relation to strength and evenness of surface-active substance adsorbed layer (defined by the chain length, nature and radical orientation) by adsorption on copper nucleus surface and decrease of interfacial tension. Even adsorption promotes formation of round shape particles; particles with deformed and non-equiaxial shape are formed at preferential surface-active substance absorption.

1. Naboychenko S. S., Shneerson Ya. M., Kalashnikova M. I., Chugaev L. V. Avtoklavnaya gidrometallurgiya tsvetnykh metallov (Autoclave hydrometallurgy of non-ferrous metals). Ekaterinburg : Ural State Technical University — Ural Polytechnical Institute, 2009. Vol. 2. 612 p. 

2. Naboychenko S. S., Klyayn S. E., Khudyakov I. F. Poroshkovaya metallurgiya = Powder metallurgy. 1973. No. 7. pp. 27–32. 

3. Naboychenko S. S., Trushin B. N. Poroshkovaya metallurgiya = Powder metallurgy. 1986. No. 7. pp. 5–8.