Acidic leaching of scheelite concentrate and production of hetero-poly-tungstate salt

Experiments on pool boiling heat transfer from a circumference-interrupted T-finned (CIT) tube and a Thermoexcel-E tube are conducted at system pressures ranging from I to 6 bars, with ethyl alcohol and R-113 as the working media. The strong effects of system pressure on the excellent boiling heat transfer performance of the two enhanced boiling tubes are presented. Based on the analyses of boiling vapor-liquid two-phase flow and heat transfer within the microchannels of the two mechanically fabricated porous layers, and by synthesizing experimental data, semiempirical correlations are established for predicting the boiling heat transfer performance of CIT and Thermoexcel-E tubes separately at atmospheric and superatmospheric pressures. © 1999 Scripta Technica, Heat Trans Asian Res, 28(8): 640-648, 1999