Copper extraction process from Tanzanian oxidized copper ore

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Section 15. Chemistry
на роторно-вакуумном испарителе до полного извлечения растворителя. Оставшуюся реакционную массу фильтруют, промывают ацетоном и сушат в термостате. Синтезированные спиро-краун эфиры получают перекристаллизацией из н-гептана в виде белых кристаллов, которые не растворимы в воде, но хорошо растворимы в органических растворителях.
2. Получение анса-краун эфиров.
Аналогично методике 1 помещают гидрохинон в среде инертного растворителя-бензола в присутствии катализатора эфирата трехфтористого бора (0,01% от реакционной массы) и добавляют по каплям оксид этилена в избыточном количестве на протяжении 2 ч. Соотношение реагирующих компонентов гидрохинон: оксид этилена 1: 8М0. Реакцию проводят при температуре 80 °C и интенсивно перемешивают еще 10−12 ч.
Реакцию конденсации проводят до прекращения выделения воды, собираемую в ловушку Дина Старка посредством азеотропной смеси бензол-вода. Раство-
ритель отгоняют на роторно-вакуумном испарителе и остаток подкисляют 5 мл концентрированной HCI (до кислой реакции по универсальному индикатору), промывают водой, фильтруют, а затем промывают ацетоном и сушат в термостате.
Состав и структуры синтезированных спиро-и анса-краун эфиров были установлены ЯМР 1 Н и ИК-спектроскопией.
ИК-спектры: присутствие полосы в области 1135−1138 см-1 характерны для краун-эфирного фрагмента, для полиэфирных цепочек 1440−1500 см-1, 1450, 1350 (vCH), 1120 (уСо)см-1.
Спектры ЯМР 1 Н, о м. д.: 8. 2−7.3 м. д., 3. 56 (с.), 4. 42 (с.), 7. 32 (м.) м. д., сигналы протонов краун-эфи-ра проявляются в виде мультиплетов в области — 4. 22.6 м. д.
Предварительные испытания полученных краун-эфиров показали выраженную способность их к комплексообразованию и высокоселективную избирательность при экстракции металлов в различных средах.
Список литературы:
1. Яцимирский К. Б., Кольцинский А. Г., Павлищук В. В., Таланова Г. Г. Синтез макроциклических соединений. Киев.: Наукова Думка, 1987, 277 с.
2. Хираока М. А., Краун соединения. Москва.: Мир, 1986, 345 с.
3. Богатский А. В. Достижения и новые тенденции в химии синтетических макроциклических комплек-сов//Биорганическая химия 1986, № 11. С. 1445−1482.
4. Фегле Ф. А., Вебер Э. Э. Химия комплексов «гость-хозяин», синтез, структуры и применение. Москва: Наука, 1988, 265 с.
5. Химический энциклопедический словарь Москва, «Советская энциклопедия» 1983, 790 с.
6. Зейналов С. Б. Спиро-краун эфиры — новый класс органических соединений. //Деп. Рук. в ВИНИТИ 03. 07. 2008, № 575, В. 2008.
7. Зейналов С. Б., Гусейнов И. Ш., Кулиев Ф. А. Новые Данные о реакции оксида этилена с кетонами//До-клады НАН Азербайджана, 2009, том LXV № 5. С. 49−52.
8. Будагова Р. Н. Спиро-краун эфиры на основе ароматических кетонов. //Деп. Рук. в ВИНИТИ 15. 03. 12, № 94 — В2012.
9. Будагова Р. Н., Зейналов С. Б. Способ получения краун-эфиров//Патент Азербайджана I 2014 0052 20. 08. 2014.
Byk Mykhaylo Volodumurovich, National Technical University of Ukraine & quot-. Kiev Polytechnic Institute", Chemical Technology Faculty, PhD in Chemistry, Associative Professor, E-mail: bmv2000@ukr. net
Copper extraction process from Tanzanian oxidized copper ore
Abstract: Copper extraction processes are widely used for pure metal obtaining in a compact or powder form and waste water purification. The process of copper extraction oxidized ore leaching solution was investigated. It
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Copper extraction process from Tanzanian oxidized copper ore
was shown that copper content in such ore reached 30% wt. and all copper can be extracted after acid leaching of grinded ore. On the base of obtained results the new scheme for environmentally friendly waste-free process for copper electrowinning proposed.
Keywords: copper electrowinning, sulphuric acid leaching, continuous process, closed production cycle.
The conventional copper electrowinning process, in spite of its present extensive use, has some drawbacks that over the last 20 years have been attempted to be overcome, but there are few implementations at the industrial level [1].
Today the world copper production extremely increased, for the last decade increasing of copper production amount 30% and copper concentrate — 37%. The world copper production reaches 16 mln. ton/year, 38%
from such amount products Chili, 7,7% - in USA. The Ukraine has a little part in world copper production and main part is for recycling of scrape metal. So the present work is actually for supplying of copper as a metal or powder and other useful byproducts obtaining.
Results and discussions: The object of investigation was rich oxidized copper ore from Tanzania which is a part of the Africa copper belt. Presented copper ore consists of:
Table 1. — Copper ore composition from RFA analysis data
Component (in oxide form) Content% wt.
Na*° 1,64
MgO 0,4
4°, 6,52
SiO2 33,7
P2O5 0,37
SO3 4,62
K2O 0,76
CaO 1,75
TiO2 0,05
0,04
MnO 0,15
9,46
CuO 37,69
SrO 0,04
BaO 0,65
It is obvious that such copper ore has a very high copper content (up to 30% wt.). The content in most others copper ores reaches only to 2−5% and contain copper in a sulfide form. Such ores needs thermal treatment to obtain copper oxide or metallic copper. The main idea of such work was to obtain pure metallic copper without thermal processes. We use diluted sulphuric acid to copper leaching, in result we obtain copper sulphate electrolyte. The metallic copper then can be extracted from solution by constant current applying (electrolysis). Obtained diluted solution can be used for copper powder obtaining by cementation process [1].
For reach copper ore with copper in oxidized form we use the next technological sequence:
1. Mechanical grinding.
2. Clay extraction.
3. Copper leaching by sulphuric acid solutions.
4. Ore rinsing
5. Ore drying
6. Copper electrodeposition
6.1 Compact copper electrodeposition
6.2 Powder copper electrodeposition
6.3 Copper cementation by iron stripes
The initial ore was grinding and separate the fraction of2−5 mm by sieving (the bigger lumps do not leach fully, but the smaller decrease leaching velocity due to caking).
The next step was clay extraction, because clay is retard acid copper extraction. The grinded ore mixed with water and after some time water with main part of clay was decanted. When all clay was separated to portion of clay diluted sulfuric acid was added and copper traces were analyzed by reaction with ammonium hydroxide solution or complexions titration by EDTA salt. There are no traces of copper in clay residue were found.
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Section 15. Chemistry
Acid copper leaching
For copper leaching we used concentrated and diluted (1: 1, 20% wt.) sulphuric acid solutions. In all cases copper are fully extracted from ore in a form of Cu 2+ ions but in a case of concentrated leaching solution the significant part of ferrous is also extracted in ion form into solution:
CuO + H2SO4^CuSO4 + H2O (1)
CuC03 • Си (ОН)2 + 2 H2SO4^ (2)
2 CuSO4 + 3 Н2 О +CO2 T ()
CuC03 + H2SO4 ¦" CuSO4 + Н2 О +CO2 T (3)
The acid was added to ore by portions (0,1 l per 1 kilo of wet ore) after some time (20 min to 60 min) of mixing solution was decant. The first portion of obtained was saturated by copper sulphate. In decanted solution some clay traces were found so obtained electrolyte was filtered before electrolysis.
Ore rinsing
The ore after leaching contain copper sulphate and sulphuric acid solutions. So such mixture was rinsed several times by water to obtaining clear solution. Qualitative analysis of copper presence was made by iron cemen-
tation probe. The stripe of 08 kp steel was immersed into solution acidified to pH 2 by sulphuric acid. If there is no copper deposited after 20 min. on steel due to cementation reaction we suppose that copper concentration is small and can be neglected.
Compact copper electrodeposition
Depends of copper concentration it is advisable obtain compact or powder copper. For compact copper deposition we use solution with copper concentration 10−60 g/l, for copper powder 1−7 g/l. From the waste waters with copper concentration smaller then 0,5 g/l we extract copper powder by cementation reaction [1].
For copper electrodeposition rectangular bathes from polypropylene or polymethylacrylate were used by volume 0. 3−2 l. Kathodes were made from stainless steel and non-soluble anodes from lead plates. The working surface of cathodes was 1,2−1,5 sq. dm. The cathode edges were insulated against dendrites. Before electrolysis cathodes were cleaned and stay on air or in water for passive film formation.
Fig. 1 — Electrodes after electrolysis
After electrolysis obtained copper foil were striped off rinsed by deionized water, dried and weight on analytical scale with accuracy of 10−4 g (Fig. 2). By obtained data current efficiency and residue copper concentration in solution.
Results were compared with analytical data. The initial current density was 1−3 А/dm 2, due to copper concentration decreasing the current density also decreases according to calculated copper concentration [2].
Electrodeposition of copper powder
When copper concentration reaches 8 g/l, the powder copper were deposited. The current density was 3−15 А/dm 2 [3]. Electrolysis time was 10−40 min. The
Fig. 2 — Copper cathode deposits after stripping off
range of copper concentration which allows obtaining fine copper powder was 2−5 g/l.
For copper powder formation copper must deposits at limiting current density. Experimental determination of limiting current was made by cathodes curves of copper deposition analysis (Fig. 3).
So limiting currents were 2,5- 1,5- 0,45 А/dm 2 for copper concentration 60- 35 and 12 g/l respectively. Calculated id values have greater values and differences increase with copper concentration increasing (Fig. 4).
On a basis of obtained results the next technological scheme for complex copper ore conversion proposed (Fig. 5).
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Copper extraction process from Tanzanian oxidized copper ore
Fig. 3 — Copper cathodic polarization curves in electrolyte with copper ions concentrations (g/l): 1−60, 3−35, 3−12
Fig. 4 — Experimental (1) and calculated (2) limiting current of copper deposition from copper ions concentration
After copper electrowinning the copper concentration in electrolyte decreased but concentration of sulphuric acid increased. So obtained weak electrolyte can be reused for leaching the next portion of copper ore. In such case sulphuric acid do not spend.
The main spending reagent in such case is electric current. For electrowinning process of compact copper current efficiency reaches 95−98%, for copper powder 55−65% end energy spending 2,5−3 and 3−5 kW*h/kg of copper respectively.
There is a lack of electricity in Tanzania but it is near to equator and Solar activity there is almost constant during all year. So we proposed to use solar panels as current sources.
The semi plant equipment was constructed (100 l volume electrolyzer, with cathode surface 1,5 m 2).
All equipment work from 3 solar panels (150 W) and has productivity 0,2 kg of copper per hour.
Conclusions: The technological process of copper leaching and sequential electrowinning proposed. The technological regimes for compact and powder copper obtaining proposed. Process is very simple and has closed production cycle. In such case there is no environmental pollution. The semi plant equipment for electrowinning process constructed.
Acknowledgments: The author is grateful for financial support and specimens of Tanzanian ore JFT Company, Kiev, Ukraine. Also author very thankful his colleagues Linucheva O. V., Donchenko M. I., Redko R. M. and Uschapovsky, D. Yu for gave scientific guidance and participated in discussions.
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Section 15. Chemistry
Fig. 5 — The complex scheme for copper ore conversion
References:
1. Grigorenko D. O., Byk M. V. Investigation of copper cementation process by iron from used electrolytes and ore leaching solutions//Austrian Journal of Technical and Natural Sciences № 3−4. — 2015. P. 64−67.
2. Donchenko, M. I.- Linyucheva, O. V.- Uschapovsky, D. Yu.- Redko, R. M.- Byk, M. V. Copper Production from a Carbonate Ores by Electrowinning Method//Naukovi visti NTUU — KPI-2013, Vol. 92 Issue 6. P. 103−108.
3. Viswanatha S G, Sajimol George Electrowinning of copper powder from copper sulphate solution in presence of glycerol and sulphuric acid//Indian Journal of Chemical Technology Vol. 18, January 2011. P. 37−44.
Islomova Yulduz Urolovna, Tashkent Institute of Chemical Technology, Senior Researcher Applicant Maksumova Oyture Sitdikovna, Tashkent Chemical Technology Institute, Doctor of Chemistry, Professor E-mail: omaksumovas@mail. ru
Research of reaction of interaction n-phthalimide with acrylic acid
Abstract: Synthesis of new reactive monomers is carried out by interaction N-phthalimide with acrylic acid. Influence of various factors is studied on their reaction: natures of catalyst and solvent. It is established that the most effective solvent of process dimethyl formamide appeares. The structure of the synthesised connections is established by methods of IR — NMR — of spectroscopy and their properties are defined.
Keywords: synthesis, reactive, N-phthalimide, acrylic acid, the catalyst, dimethyl formamide.
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