Recovery of Tellurium(Te) from Waste Thermoelectiric Modules by Aqua Regia Leaching and Solvent Extraction

This study is aimed at developing a hydrometallurgy technology for recovering and recycling tellurium from waste thermoelectiric modules. The thermoelectric module powders were classified into ±1mm after comminution, and the weight ratios were separated into 47.0% and 52.9% for oversize and undersize, respectively. The contents of Te and Cu showed 0.1% of Te and 48.6% of Cu in + 1mm, and Te 21% and Cu 2.3% in –1mm. This result indicates that the tellurium in the thermoelectric module could be concentrated and separated from the main impurity Cu by comminution followed by sieving. The HCl leaching test results showed that 98% of Cu, Fe, Ni, Pb, and Sn was extracted. The leaching efficiencies of Al, Sb and Bi were 96%, 85% and 73%, respectively, while Se and Te were leached less than 1%. Aqua-regia leaching was chosen to recover Te from the leach residue, and Te, Bi, Sb, and Cu were dissolved in the leaching solution. The metal concentration in the solution was Te 78%, Bi 18%, Sb 3% and other metals were less than 1%. The solvent extraction of tellurium in simulated solution showed that more than 99% of Te was extracted at 30% TBP, O / A ratio of 1:1, pH = -1.3 and reaction time of 5 min. It was confirmed that Te and Bi could be separated by adding nitric acid. Te and Sb could be separated by adding hydrochloric acid. Tellurium ion precipitated as tellurium oxide powder by adding water to the purified tellurium solution and adjusting pH to 4-7. Finally, by the new recycling process, more than 98% of Te was recovered and the pure Te oxide was obtained.|이 연구는 폐열전모듈로부터 텔레륨을 회수하기 위한 습식제련공정을 개발하기 위하여 수행되었다. 폐열전모듈은 분쇄된 후 1 mm 이상과 이하로 분리되었고 무게비는 1 mm 이상이 47.0% 그리고 이하가 52.9%로 나타났다. 텔레륨과 구리의 함량은 1 mm 이상에서 각각 0.1%과 48.6%이었으며 1 mm 이하의 시료에서는 텔레륨과 구리 함량이 21%와 2.3%로 분쇄후 체질에 의해서 텔레륨 성분이 농축되고 주요 불순물인 구리가 분리되는 것이 확인되었다. 염산침출결과는 구리, 철, 니켈, 납과 주석이 98% 침출되고 알루미늄과 안티모니, 비스무스는 각각 96%, 85%, 73% 침출되는 것으로 나타났다. 이에 비하여 셀레늄과 텔레륨은 1% 이하의 침출율을 나타내어 다른 성분에 비하여 잔사에 농축되었다. 왕수침출이 텔레륨을 침출잔사로부터 회수하기 위해 수행되었다. 이 용액에 텔레륨, 비스무스, 안티모니, 구리가 존재하며, 농도는 각각 78%, 18%, 3%, 나머지는 1% 이하였다. 텔레륨 용매추출실험은 모의 용액을 이용하여 수행되어 30% TBP, O/A ratio 1:1, pH = -1.3 그리고 반응시간 5분에서 99%의 텔레륨이 추출되는 것을 확인하였다. 텔레륨과 비스무스는 질산 첨가에 의해 분리되고, 텔레륨과 안티모니는 염산 첨가에 의해 분리되는 것이 확인되었다. 중화침전으로 텔루륨을 분말로 회수하기 위해 정제된 텔루륨 수용액에 물을 첨가하여 pH를 4~7사이의 중성 영역으로 조절하여 산화텔루륨 침전물로 회수하였다. 당 연구에서 개발된 공정에 의해 98%의 텔레륨이 회수되고, 순수한 산화텔레륨이 회수되는 것이 확인되었다.제 1 장 서 론 1 1.1 연구배경 및 개요 1 1.2 연구내용 4 제 2 장 이론적 배경 5 2.1 열전소자 5 2.2 파·분쇄(Comminution) 6 2.2.1 파·분쇄 이론 6 2.3 침출(Leaching) 8 2.3.1 침출의 정의 8 2.3.2 침출제의 조건 9 2.4 용매추출(Solvent Extraction) 10 2.4.1 추출제(Extractants) 12 2.4.2 희석제(Diluent) 14 2.4.3 추출기구(Extraction Mechanism) 14 제 3 장 실험재료 및 실험방법 17 3.1 실험 시료 17 3.2 함량 분석 18 3.3 파·분쇄 및 선별 실험 19 3.3.1 파·분쇄 19 3.3.2 입도 분급 20 3.4 침출 21 3.4.1 실험 장치 21 3.4.2 실험 방법 21 3.5 용매추출 23 3.5.1 실험 장치 23 3.5.2 실험 방법 23 제 4 장 실험결과 25 4.1 절단 파쇄 (Cut crusher) 25 4.2 분쇄 (Milling) 26 4.3 입도 분급 27 4.4 침출 28 4.4.1 염산을 이용한 선택적 침출에 의한 불순물 분리 29 4.4.2 염산 침출 잔사의 왕수 침출 34 4.5 용매추출 실험 35 4.5.1 모의용액의 용매추출 36 4.5.2 폐 열전모듈 침출액의 용매추출 41 4.6 텔루륨 중화침전 47 4.7 텔루륨 회수공정도 49 제 5 장 결론 50 참고문헌 52Maste

Prognostic Significance of the Tumor Volume and Tumor Percentage for Localized Prostate Cancer

PURPOSE: Tumor volume has been thought to be an important predictive factor for significant prostate cancer. We assessed the impact of the tumor volume(TV) and the tumor percentage(TP) of radical prostatectomy specimens on the pathological variables and the oncological outcome. MARERIALS AND METHODS: The tumor percentage and tumor volume were calculated for 525 cases by a single pathologist who determined the volume based on the surface area of the slides involved by tumor of the prostate. Univariate and multivariate logistic regression analyses were used to characterize the association of TP categories(20%) and TV(7.5cc) with the clinicopathological variables. Biochemical recurrence(BCR) was estimated using Kaplan-Meier analysis and Cox's hazard regression model. RESULTS: The mean prostate cancer volume was 6.5+/-8.5cc(median: 3.8, range: 0.04-73.8) and the mean percent tumor composition was 0.17+/-0.19 (median: 0.1, range: 0.01-0.95). A higher tumor volume and a higher tumor percentage were associated with extra-capsular extension(ECE), a positive surgical margin(PSM), a higher pT stage and a higher prostate-specific antigen(PSA) Gleason score(all p<0.05). In addition, TP was the independent predictor of ECE(adjusted odds ratio(OR): 22.66, 95% confidence interval(CI): 1.801-285.079, p=0.016), but the tumor volume was not associated with ECE on the multivariate logistic analyses. On the Kaplan-Meier analysis, but not on the Cox-hazard analyses, the TP did demonstrate a significant association with biochemical recurrence(p=0.035), yet the TV did not reach statistical significance(p=0.190). CONCLUSIONS: Our data indicates that the tumor percentage had a significant effect on the BCR on the Kaplan-Meier analysis. The tumor percentage rather than the tumor volume might be more useful to predict the prognosis of prostate cancer

Pathologic Outcome of Unilateral Low Risk Prostate Cancers on Multicore Prostate Biopsy after Radical Prostatectomy

PURPOSE: To investigate clinicopathologic characteristics of unilateral, low risk prostate cancers detected via multi(>or=12)-core prostate biopsy. MATERIALS AND METHODS: One hundred four patients who underwent radical retropubic prostatectomy(RRP) for unilateral, low risk prostate cancer (clinical stage or=12)-core prostate biopsy were enrolled. In this retrospective study, we reviewed the patients' preoperative and pathologic data to assess potential predictors of pT2c or greater disease at the time of RRP, as well as characteristics of such disease. RESULTS: Of the 104 subjects, only 34(32.7%) were pathologically-proven to have unilateral disease, while the others showed pathologically-bilateral or worse disease from analysis of the RRP specimens. Subjects pathologically found to have uni- and bi-lateral disease showed no significant differences regarding age, prostate-specific antigen(PSA), free-to-total PSA ratio, prostate volume, clinical stage, number of positive cores, biopsy Gleason score, number of total biopsy sites, and highest percentage of tumor at any biopsy site. Multivariate logistic regression analysis revealed no significant preoperative predictors of pT2c or greater disease at RRP. CONCLUSIONS: Most patients with unilateral, low risk prostate cancer detected on multi(>or=12)-core prostate biopsy actually had pathologically- worse disease. For clinically-localized prostate cancer, a more accurate method to identify appropriate candidates for unilateral or focal ablative therapy should be developed

Prognostic Significance of Multifocal Tumor in Radical Prostatectomy

Purpose: We investigate the impact of tumor multifocality on the biochemical recurrence rate after radical prostatectomy. Materials and Methods: Data was collected from 525 patients who underwent radical prostatectomy for clinically localized prostate cancer from 2003 to 2007. We evaluated the potential associations of multifocality with various clinical and pathologic factors. The ability to predict extra-capsular extension (ECE) was tested by logistic regression models, whereas biochemical recurrence (BCR) was assessed via Kaplan-Meier analyses and Cox-hazard regression models. The BCR was defined as a level of serum prostate-specific antigen (PSA) of 0.2ng/ml or greater on consecutive evaluations. Results: Multifocality was observed to be significantly associated with the presence of a high grade Gleason pattern (p=0.014), the pT stage (p＜ 0.001), ECE (p=0.005) and a positive surgical margin (PSM) (p=0.019). Moreover, it was the independent predictor of ECE on multivariate logistic regression analyses (p=0.039). However, although multifocality had a significant influence on biochemical recurrence on the Kaplan-Meier analyses (log rank test, p=0.019), only the PSA level and the Gleason score were significant predictors of BCR on the multivariated Cox-hazard analyses. Conclusions: Although multifocality was associated with adverse pathologic features, it had no significant effect on biochemical recurrence on the multivariated cox-hazard analyses