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Fe_(3)O_(4)对黄铜矿在酸性硫酸铁溶液中铜溶解氧化还原反应的影响

Transactions of Nonferrous Metals Society of China 2024年第6期34卷 1965-1975页

作者： kolela j nyembwe Elvis FOSSO-KANKEU Frans WAANDERS Martin MKANDAWIRE Didier K nyembwe Bhekie B MAMBA Water Pollution Monitoring and Remediation Initiatives Research Group School of Chemical and Minerals EngineeringFaculty of EngineeringNorth-West UniversityPotchefstroomSouth Africa Department of Mining Engineering College of Science Engineering and TechnologyUniversity of South AfricaFlorida Science CampusJohannesburgSouth Africa Department of Metallurgy Faculty of Engineering and Built EnvironmentUniversity of JohannesburgDoornfonteinJohannesburgSouth Africa Department of Chemistry School of Science and TechnologyCape Breton UniversityCanada School of Mining Metallurgy and Chemical EngineeringFaculty of Engineering and the Built EnvironmentUniversity of JohannesburgJohannesburgSouth Africa Institute for Nanotechnology and Water Sustainability College of Science Engineering and TechnologyUniversity of South AfricaFlorida Science CampusJohannesburgSouth Africa

由于钝化层的形成,黄铜矿(CuFeS_(2))在氧化条件下浸出通常具有溶解速率缓慢的特点。为了将黄铜矿浸出过程中的钝化效应降至最低并提高铜的回收率,研究了CuFeS_(2)在不同pH值(1.0、1.5和1.8)和温度(25和50℃)条件下浸出时,向Fe_(2)(SO_(... 详细信息

由于钝化层的形成,黄铜矿(CuFeS_(2))在氧化条件下浸出通常具有溶解速率缓慢的特点。为了将黄铜矿浸出过程中的钝化效应降至最低并提高铜的回收率,研究了CuFeS_(2)在不同pH值(1.0、1.5和1.8)和温度(25和50℃)条件下浸出时,向Fe_(2)(SO_(4))_(3)−H_(2)SO_(4)浸出剂中添加磁铁矿(Fe_(3)O_(4))对铜溶解速率的影响。结果表明,溶液pH值、电位和温度在溶解过程中起着关键作用。在pH 1.8、50℃和400 mV的条件下,Fe_(3)O_(4)−CuFeS_(2)混合体系中铜的回收率达到最大值(70%),而未添加Fe_(3)O_(4)时,CuFeS_(2)中铜的回收率较低(48%)。添加Fe_(3)O_(4)有助于维持较高的氧化还原值。添加Fe_(3)O_(4)还使活化能从79.04 kj/mol降低到53.69 kj/mol。这表明,当Fe_(3)O_(4)存在时,由于形成了更易溶解的中间体斑铜矿(Cu_(5)FeS_(4))和辉铜矿(Cu_(2)S),CuFeS_(2)更易被氧化。两种溶解过程都受到矿物表面的化学控制。此外,对浸出残渣的矿物学分析表明,当无Fe_(3)O_(4)存在时,作为表面钝化物的黄钾铁矾浓度较高。因此,添加Fe_(3)O_(4)减少了钝化层的形成,提升了铜的回收率。

关键词：黄铜矿溶解磁铁矿电偶钝化

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Structural, compositional and mineralogical characterization of carbonatitic copper sulfide: Run of mine, concentrate and tailings

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International journal of Minerals,Metallurgy and Materials 2019年第2期26卷 143-151页

作者： kolela j nyembwe Elvis Fosso-Kankeu Frans Waanders Kasongo D nyembwe Water Pollution Monitoring and Remediation Initiatives Research Group School of Chemical and Minerals Engineering Faculty of Engineering North-West University School of Mining Metallurgy and Chemical Engineering Faculty of Engineering and the Built Environment University of Johannesburg

The aim of this study was to determine the structural, compositional, and mineralogical composition of carbonatitic copper sulfide concentrator plant streams. Three samples, each from a different stream(run of mine(ROM), concentrate, and tailings) of a copper concentrator were characterized using various techniques, including stereomicroscopy, X-ray fluorescence, X-ray diffraction, Fourier transform infrared(FTIR) spectroscopy, scanning electron microscopy(SEM) in conjunction with energy-dispersive X-ray spectroscopy(EDS), and optical microscopy. The results reveal that each stream possesses its own unique compositional features. Carbonate minerals associated with calcite and dolomite, followed by quartz, remain the major minerals in both the ROM and tails streams. In the ROM stream, chalcopyrite appears to occur as veins within the carbonatite-hosting ore body. Mineral phase mutation was discovered in the tails stream because magnetite formerly identified in the ROM as the primary iron oxide had evolved into hematite. This metamorphosis was likely promoted by the concentration process. The concentration process was effective, upgrading the chalcopyrite content from 2 wt% in the ROM stream to 58 wt% in the concentrate stream; it was accompanied by bornite(4 wt%), anilite(3 wt%), and digenite(2.5 wt%). In addition, the concentrate stream exhibited properties distinctive from those of the other streams. The FTIR analysis showed the existence of a sulfide group related to the chalcopyrite mineral. Free chalcopyrite grains were observed in the concentrate by SEM analysis, and their mineral presence was supported by the EDS analysis results. All characterization techniques corresponded well with each other regarding the structure, chemistry, and composition of the samples.

关键词： chalcopyrite mineral characterization phase mutation concentrate streams

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pH-dependent leaching mechanism of carbonatitic chalcopyrite in ferric sulfate solution

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Transactions of Nonferrous Metals Society of China 2021年第7期31卷 2139-2152页

作者： kolela j nyembwe Elvis FOSSO-KANKEU Frans WAANDERS Martin MKANDAWIRE Water Pollution Monitoring and Remediation Initiatives Research Group School of Chemical and Minerals EngineeringFaculty of EngineeringNorth-West UniversitySouth Africa Department of Chemistry School of Science and TechnologyCape Breton UniversityCanada

The dissolution of a carbonatitic chalcopyrite(CuFeS2)was studied in H_(2)SO_(4)−Fe_(2)(SO_(4))_(3)−FeSO_(4)−H_(2)O at varying pH values(0.5−2.5)and 25℃ for 12 *** were conducted with a size fraction of 53−75μ*** Cu recoveries,below 15%,were observed in all pH *** results from the XRD,SEM−EDS,and optical microscopic(OM)analyses of the residues indicated that the dissolution proceeded through the formation of transient ***_(3.39)Fe_(0.61)S_(4) and Cu_(2)S were the intermediate phases at pH 0.5 and 1.0,respectively,whereas Cu_(5)FeS_(4) was the major mineral at pH 1.5 and *** thermodynamic modelling predicted the sequential formation of CuFeS_(2)→Cu_(5)FeS_(4)→Cu_(2)S→*** soluble intermediates were Cu_(5)FeS_(4) and Cu2S,whilst,CuS and Cu_(3.39)Fe_(0.61)S_(4) were the refractory phases,supporting their cumulating behaviour throughout the *** obtained results suggest that the formation of CuS and Cu_(3.39)Fe_(0.61)S_(4) could contribute to the passive film formed during CuFeS_(2) leaching.

关键词： chalcopyrite carbonatite chemical leaching leaching mechanism intermediate phase thermodynamic behavior

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Laparoscopic Pyelolithotomy: Initial Experience with 62 Patients

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Open journal of Urology 2022年第1期12卷 74-82页

作者： Cyril Kamadjou Annie Kameni Dolly Bilonda kolela Bertin Njinou Ngninkeu Fru Angwafor Medical and Surgical Center of Urology Douala Cameroon Department of Surgery and Specialities Faculty of Medicine and Pharmaceutical Sciences University of Douala Douala Cameroon Coordinator Urology Residency Program Faculty of Medicine and Biomedical Sciences University of Yaounde Yaounde Cameroon

Objective: To evaluate the role of the laparoscopic approach in the management of pelvic calculi in a urology centre in Douala, Cameroon. Materials and Methods: This was a retrospective study carried out from 2014 to 2019 involving 62 patients with calculi at the renal pelvis managed through laparoscopic pyelolithotomy. Results: We recruited 62 patients (38 men and 24 women) with a median age of 36 [25 - 48] years. Nephritic colic was the most frequently encountered presenting complaint (92% of cases). In 56.45% of cases, the stone was on the left side of the body. Twelve patients had kidney acute failure at the time of diagnosis. Five patients received antibiotics for urinary tract infections before the operation. Before surgery, eight double j stents were placed in 8 patients;in five because of urinary tract infection and in three because of nephritic colic. In all the cases, the definitive diagnosis was made using abdominal CT scans. The median size of the calculi was 22 [17 - 28] mm. Dilatation of the pyelocaliceal cavity was noticed in all the patients. The median surgery duration was 100 [90 - 120] minutes. Drainage of the urinary tract using a double j stent was performed in all the patients, whereas percutaneous drainage was performed only in 9.67% of cases. There was no case of conversion to open surgery. Control ultrasound performed one month after the removal of the double j stent did not reveal any residual stones in the pyelocaliceal cavities. Conclusion: Laparoscopic pyelolithotomy is a mini-invasive technique that is adequate for the management of voluminous pelvic calculi.

关键词： Laparoscopic Pyelolithotomy Pelvic Calculi Cameroon

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Evaluation of Extracorporeal Shockwave Lithotripsy in the Management of Renal and Ureteral Calculi

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Open journal of Urology 2021年第12期11卷 474-485页

作者： Cyril Kamadjou Calson Ambomatei Achille Mbassi Annie Kameni Dolly Bilonda kolela Fru Angwafor Medical and Surgical Center of Urology Douala Cameroon Faculty of Medicine and Pharmaceutical Sciences Department of Surgery and Specialities University of Douala Douala Cameroon Elisabeth Glaser Pediatric AIDS Foundation Buea Cameroon Central Hospital Yaounde Cameroon Coordinator Urology Residency Program Faculty of Medicine and Biomedical Sciences University of Yaounde Yaounde Cameroon

Aim: To evaluate the efficacy of extracorporeal lithotripsy in the management of renal and ureteric calculi in a urology center in Douala, Cameroon. Materials and Methods: This is a retrospective study carried out over six years, between january 2014 and December 2020. All the patients were treated using a Direx Integra lithotripter, with the number of shockwaves ranging from 1200 to 3500, without anaesthesia and were discharged a few hours after the procedure on the same day. In a majority (63.75%) of the cases, the calculi were incidental findings. A Double-j stent was indicated in two patients and preceded extracorporeal lithotripsy because of renal colic and signs of urinary tract infection. Results: We recruited a total of 122 patients with a mean age of 42.19 ± 13.08. We had 65 (53.3%) males and all patients had at least one calculus confirmed by CT scan with a mean size of 13.84 ± 4.17 mm, 85 (69.7%) patients became completely stone-free after a maximum of four sessions of extracorporeal lithotripsy (ESWL). 21 (17.2%) patients had intermediate results, being asymptomatic and/or having less than three residual fragments that measured less than 4 mm. The failure rate was 13.9%, with 17 patients still having more than three fragments measuring more than 4 mm after 4 ESWL sessions. 1 (0.8%) had septic shock as a post ESWL complication while 6 (4.9%) benefitted from a complimentary medical and/or surgical treatment (double j stent placement). Conclusion: The management of renal and ureteral calculi through extracorporeal lithotripsy in adults seems to be particularly effective for renal calculi measuring less than 20 mm and ureteral calculi measuring less than 15 mm. Extracorporeal lithotripsy, which can be performed on an outpatient basis (and without anaesthesia) is associated with minimal complications, and remains the option of choice for most upper urinary tract calculi.

关键词： Renal and Ureteric Calculi Extracorporeal Lithotripsy Double-j Stent

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