The suspension of copper droplets in the slag is considered. The copper/slug suspension is delivered as the product from the direct-toblister process which is applied in the KGHM – Polska Miedź (Polish Copper) S.A. factory. The droplets / slag suspension was treated by a special set of reagents (patented by the authors) to improve the coagulation process. On the other hand, the observations are made to estimate if the melting / reduction process in the furnace is sufficiently effective to avoid a remaining of carbon in the copper droplets. The coagulation process was carried out in the crucible (laboratory scale). However, conditions imposed to the coagulation / solidification process in the laboratory scale were to some extent similar to those applied usually in the industry when the suspension is subjected to the analogous treatment in the electric arc-furnace. Some suggestions are formulated how to improve the industrial direct-to-blister process.
The suspension of the copper droplets in the post-processing slag taken directly from the KGHM-Polska Miedź S.A. Factory (from the direct-to-blister technology as performed in the flash furnace) was subjected to the special treatment with the use of the one of the typical industrial reagent and with the complex reagent newly patented by the authors. This treatment was performed in the BOLMET S.A. Company in the semi-industrial conditions. The result of the CaCO3, and Na2CO3 chemicals influence on the coagulation and subsequent sedimentation of copper droplets on the crucible bottom were subjected to comparison with the sedimentation forced by the mentioned complex reagent. The industrial chemicals promoted the agglomeration of copper droplets but the coagulation was arrested / blocked by the formation of the lead envelope. Therefore, buoyancy force forced the motion of the partially coagulated copper droplets towards the liquid slag surface rather than sedimentation on the crucible bottom. On the other hand, the complex reagent was able to influence the mechanical equilibrium between copper droplets and some particles of the liquid slag as well as improve the slag viscosity. Finally, the copper droplets coagulated successfully and generally, were subjected to a settlement on the crucible bottom as desired / requested.
Coagulation and solidification of the copper droplets suspend in the liquid slag are usually accompanied by the appearance of the Cu-Cu2O eutectic. Locally, this eutectic is created in the stationary state. Therefore, frequently it has a directional morphology. Since the E = (Zn) + Zn16Ti – eutectic is similar in the asymmetry of the phase diagram to the Cu-Cu2O – eutectic, the (Zn) single crystal strengthened by the E = (Zn) + Zn16Ti precipitate is subjected to directional growth by the Bridgman’s system and current analysis. Experimentally, the strengthening layers (stripes) are generated periodically in the (Zn) – single crystal as a result of the cyclical course of precipitation which accompanies the directional solidification. These layers evince diversified eutectic morphologies like irregular rods, regular lamellae, and regular rods. The L – shape rods of the Zn16Ti – intermetallic compound appear within the first range of the growth rates when the irregular eutectic structure is formed. Next, the branched rods transform into regular rods and subsequently the regular rods into regular lamellae transitions can be recorded. The regular lamellae exist only within a certain range of growth rates. Finally, the regular rods re-appear at some elevated growth rates. The entropy production per unit time and unit volume is calculated for the regular eutectic growth. It will allow to formulate the entropy production per unit time for both eutectic structure: rod-like and lamellar one.