Degang Li

Improving the Leaching of Vanadium From Petroleum Coke

The mechanism of strengthening the leaching of vanadium from petroleum coke by surfactant was investigated. When the surfactant was used, the leaching efficiency was improved, the leaching amount of vanadium increased from 390 to 540 ppm at 303 K. The surface physical chemical properties of the leaching solution, such as the conductivity, the surface tension, contact angle, and zeta potential were studied before and after the surfactant is added. The zeta potential increased from –20 to 40 mV, when the surfactant was used from 0 to 700 mg/L, and the surface tension and contact angle decreased significantly first, then remained constant; the interface energy increased. All the change of physical chemical properties enhanced wetting capability and combination adhesion. And this improved the leaching efficiency.

Synthesis of pentaerythritol adipate ester-based Zinc Alkoxide and its thermal stability on PVC

Because of the excellent corrosion resistance, antiflaming and electrical insulation, PVC (poly vinyl choride) has become one of the five commonly used plastics in the world.1,2 However, PVC has significant defects due to its quick decomposition at temperature higher than 130°C.3–5 This process results in a significant change in color, reducing the mechanical properties and the generated HCl exacerbates the decomposition of PVC, so the usage of PVC thermal stabilizers is inevitable.4,6 Our group had synthesized pentaerythritolbased zinc alkoxide (PE-Zn) as a thermal stabilizer.7 PE-Zn has outstanding performances in terms of color stability and long-term stability of rigid PVC. However, most of the alkoxide have high melting point and poor compatibility with PVC, which significantly restrict their wide applications. In order to decrease the melting point of polyols-based metal alkoxide, an ester group, such as stearic acid, was grafted onto the polyols to obtain pentaerythritol stearate esterbased zinc alkoxide.8