Li Qinggang

Study on the Removal of MIBK from Aqueous Solution by Vacuum Membrane Distillation

Methyl isobutyl ketone(MIBK) is widely used as extraction agent in hydrometallurgy. As it has a definite solubility in water, so when using MIBK as extraction agent, there will be MIBK in stripping solutions inevitably, which not only pollutes working conditions, but also affects the quality of ultimate product. In order to remove MIBK from aqueous solutions, the means of flat vacuum membrane distillation(VMD) is studied in the paper. The area of the membrane used in the study is 0.02 m2, the initial volume of feed is 2 L, each experiment was conducted over a time period of 60–120 min. The influences of the factors such as temperature(34.8–55.0 °C); pressure in the permeate side(10.67–14.67 kPa) and feed flow rate(27.8–69.4 mL/s) were experimentally studied. Increasing the temperature or reducing the pressure in the permeate side results in a faster removal of MIBK; however there is a decrease in removal factor β, increasing the feed flow rate results in a faster removal of MIBK and an increase of removal factor β, especially in the range of lower flow rate. The study indicates that the aim of MIBK removal and recycle from dilute aqueous solutions can be achieved by VMD.

Electrodeposition of copper by IMPC method

In order to develop an energy-saving electrodeposition process of copper, the electrodeposition of copper in copper sulfate solution by the ion-exchange membrane primary cell (IMPC) method has been studied. The experiments were carried out in an ion-exchange membrane primary cell with dimensions of 200 mm in length, 52 mm in width and 90 mm in height. The influences of temperature (294–323 K), interval between the anode and cathode (1.5–3.5 cm), mass concentrations of Cu2+ (6–40 g/L), H2SO4 (0–120 g/L) and Fe3+ (3–9 g/L) in catholyte and solution flow rate (0–8 cm/s) on current density and current efficiency were investigated experimentally. The current density increases with the increase of temperature and concentrations of Cu2+ and H2SO4 in catholyte. Cathode current efficiency decreases with the increase of concentration of Fe3+ in catholyte and anode current efficiency decreases with the increase of temperature. The high-quality cathodic copper can be obtained and the current density of membrane can be higher than 150 A/m2 and the current density of cathode can be higher than 300 A/m2. The experiment results show that IMPC method is effective for electrodeposition of copper.

Removal of organic matter from H2TaF7 solution by adsorption

The removal of organic matter from H2TaF7 solution by adsorption was investigated in order to reduce the carbon content in the K2TaF7 crystal. Three kinds of adsorbent, LSA-5 resin, LSA-20 resin and active carbon were applied in the fixed bed respectively. Experimental results indicate that LAS-5 resin, LAS-20 resin, the mixture of LAS-5 resin and LAS-20 resin (with volume ratio of 1:1), and the active carbon can all reduce chemical oxygen demand (COD) value of the H2TaF7 solution, and reduce consequently carbon content of K2TaF7 crystal to 0.0010%–0.0015% from 0.0025%–0.0030%. Comparing with the others, the active carbon is an approved adsorbent whose bed volumes of effluent reaches 70. In addition, there is a linear relationship between the COD value of H2TaF7 solution and the carbon content in K2TaF7 crystal, and the carbon content in K2TaF7 crystal decreases with the decreasing of COD value of H2TaF7 solution. When the COD value of H2TaF7 solution is lower than 7 mg/L, the carbon content in K2TaF7 crystal would decrease to less than 0.0015%.