[Emission Characteristics and Control of Heavy Metals in Secondary Copper Smelting Process].

Secondary copper smelting is an important source of heavy metal emission. Flue gas samples were collected from different stages in secondary copper smelters to study the emission characteristics and control of particulate matters (PM) and heavy metals such as Cd, Cr, As, Pb, Sn, and Sb. The mass concentrations of heavy metals in flue gas and fly ash were determined using inductively coupled plasma-mass spectrometry. The emission factors of heavy metals were estimated. The results showed that the mass concentrations of heavy metals and PM in the flue gas were high in the cooling stage. After passing through a series of air pollution control devices, such as a bag filter and adsorption tower, the heavy metals and PM were simultaneously removed with a removal efficiency of 80%-99%. The concentration order of heavy metals in the stack gas from different anode furnace stages followed feeding-fusion>oxidation≈deoxidization. In general, the mass concentrations of heavy metals and PM in the stack gas could meet the industry emission standards. The average emission factors of As, Pb, Cr, Sn, Sb, and Cd were 2.6×103, 2.4×103, 2.7×103, 5.6×102, 34.1, and 9.8 mg·t-1, respectively. This could provide data support for estimating the annual emission amounts of heavy metals from the secondary copper industry and establishing the emission inventories. The fly ash contained high concentrations of Cu and Zn, which can be recycled as raw materials for recycling the valuable metals.

Application of Component Apheresis in Pre-deposited Autotransfusion.

OBJECTIVE: This study aims to evaluate the effects of preoperative autologous blood donation (PABD) using apheresis in patients who underwent elective surgical procedures, and investigate its clinical usefulness. METHODS: Data from 109 patients who underwent general and orthopedics elective surgery were analyzed in this study. Patients were divided into three groups: control group, patients who did not donate autologous blood; whole blood (WB) PABD group, patients who underwent preoperative autologous WB donation; autologous apheresis group, patients who donated autologous blood using erythrocytapheresis. Hb, Hct, and PLT levels in all patients were measured and compared before the operation and on postoperative days one and three. Furthermore, postoperative recovery indexes in the three groups were compared including allogeneic blood transfusions and postoperative hospitalization days. RESULTS: Hb, Hct, and PLT levels in the three groups after the operation were lower than levels before the operation. However, Hb levels were higher than 110 g/L and the Hct levels were not less than 33%. Differences in Hb and Hct drop values on postoperative days one and three among the three groups were statistically significant (P>0.05). Furthermore, PLT level in the control group was lower than in the WB PABD group and autologous apheresis group (P<0.05). PABD using erythrocytapheresis reduced blood transfusion (P<0.05). CONCLUSION: Erythrocytapheresis PABD led to an equal or even better postoperative recovery effect than WB PABD, and erythrocytapheresis PABD is feasible for blood transfusion therapy in patients undergoing elective surgical procedures.

[Assessment of Emission and Co-Reduction of PCDD/Fs and PCNs in the Secondary Copper Production Sector].

Polychlorinated naphthalenes (PCNs) could he generated and discharged unintentionally in the secondary copper production industry with similar mechanisms as PCDD/Fs during high-temperature industrial processes. Therefore, measures that reduce the release of PCDD/Fs will also reduce PCNs emissions. Analysis of the technical process and correlation with their emissions will provide theoretical basis for co-mitigation of PCNs and PCDD/Fs. The production process of secondary copper was analyzed, with key production stages of discharge identified through monitoring the emissions of two kinds of pollutants. Co-reduction technologies were screened and specified. Three recommendations on co-mitigation of the two pollutants were provided to support the implementation of Stockholm Convention and UPOPs reduction in the secondary copper production sector in China. Key words:secondary copper industry; smelting; PCNs; PCDD/Fs; co-mitigation

[Pollution patterns and health risk assessment for polychlorinated biphenyls in soils from a capacitor storage site].

Concentration profiles of polychlorinated biphenyls (PCBs) and toxicity risks of dioxin-like PCBs were investigated in soils collected from a capacitor-burial site. Based on the USEPA model of human health risk assessment, cancer and non-cancer risks for these soils were also estimated when used for residential and industrial purposes. It was observed that the average concentrations of total PCBs (sigma PCBs, 22 congeners) in the soils were 6.23, 19.3, and 1 540 mg x kg(-1) at different depths of 0-30 cm, 30-100 cm, and 200-250 cm, respectively. Tri-CBs and Tetra-CBs were the largest contributors to the total concentrations in the soils, making up 75.7%-94.0%. The toxic equivalent concentration (TEQs) of total PCBs was up to 457 microg x kg(-1), and PCB 126 had the highest contribution. Health risk assessment showed that under residential land uses, children was the most sensitive receptor although cumulative non-carcinogenic risks for both children and adults (0.927-1 760) nearly exceeded the acceptable level, while under industrial land uses except for the topsoil, the total non-carcinogenic risks for workers exceeded the acceptable level. Under residential and industrial land uses, PCBs in the soils had high carcinogenic risks that were more than the acceptable level of carcinogenic risks (10(-6)-10(-5)). Inhalation exposure was the major way subjected to the carcinogenic risk as well as to the non-carcinogenic risk, regardless of children, adults, and workers involved.

[Analysis of characteristics of dioxin contamination in the chlor-alkali site that uses graphite anode for production].

In order to find out the characteristics of dioxin contamination, we sampled and analyzed the soil and groundwater on a chlor-alkali factory site that uses graphite anode for production. The results show that the toxic equivalent quantity (TEQ) of dioxins in soil samples exceeds the U. S. EPA region screening value (RSL), with the chlorine hydrogen processing workshop, the electric tank workshop, the asbestos stack area, the sewage treatment plant and the oil depot were affected. The dioxin concentration limit of the groundwater sample doesn't exceed the drinking water standard of China. Considering the fingerprints characteristics of dioxin-contaminated concentration, dioxin isomers content and TEQ, the priority pollutants for control on this site are 2,3,7,8-TCDF, 2,3,4,7,8-PeCDF, 1,2,3,4,7,8-HxCDF, OCDD and 2,3,7,8-TCDD. The results show that dioxin pollution is very serious in the chlor-alkali plant that uses graphite anode for production, and the environmental supervision is imperative.