PILOT PLANTS. Manganese Concentration from Low Grade Domestic Ore. Nossen Nitric Acid Cycle.

This article describes the problems of deterioration of the quality of processed raw materials due to depletion of mineral resources. It is proposed to use nitric acid for the processing of complex refractory low-grade concentrates containing non-ferrous and noble metals. It was found that the studied concentrate contains: sphalerite (26.9 %), pyrite (22.0 %), chalcopyrite (19.9 %), silica (13.9 %), alumina (5.5 %), galena (1.7 %), oxidized forms of iron (Fe2O3) (12 %). Gold and silver are associated with sulfide minerals. Typical reactions of interaction of these minerals with nitric acid are considered. A sufficiently high thermodynamic probability of these reactions in a wide temperature range is established. With the use of mathematical methods, the optimal conditions of the process of nitric acid leaching are selected: the ratio of L:S = 5:1; the concentration of nitric acid 10 mol/L; the duration of the process is 60 minutes. In this case, the extraction of copper, zinc, iron and sulfur into the solution was 99.00 %, 99.84 % 98.60 %, 88.51 %, respectively.

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Obtaining of High Quality Iron Oxide from Nitric Acid Leaching Solution

Solid State Phenomena ◽

10.4028/www.scientific.net/ssp.299.1128 ◽

2020 ◽

Vol 299 ◽

pp. 1128-1133

Author(s):

Andrey A. Shoppert ◽

Denis A. Rogozhnikov ◽

Y.E. Agapitov

Keyword(s):

Iron Oxide ◽

Nitric Acid ◽

Copper Content ◽

Acid Leaching ◽

Low Grade ◽

Ferrous Ions ◽

High Quality ◽

Nitric Acid Leaching ◽

Promising Source ◽

Pregnant Solution

Low grade copper concentrate is a promising source for the future recovery of copper and other valuable components by nitric acid leaching, which leads to a formation of iron rich pregnant solution. In this study a method of producing of high-quality iron oxide from the pregnant solution by precipitation of jarosite with subsequent conversion of jarosite into magnetite under alkaline conditions in the presence of ferrous ions was explored. The degree of iron extraction was 87.4%, the copper content in the magnetite was 0.06% under the following optimal conditions of jarosite precipitation: precipitation time 6 h, initial pH 1.5, seed amount 60 g/L. However, to obtain this purity, the copper content in the pregnant solution should be less than 0.5 g/L, and as a seed, it is necessary to use a well-crystallized jarosite with a low content of impurities.

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Leaching of low-grade manganese ores by using nitric acid and glucose: optimization of the operating conditions

Hydrometallurgy ◽

10.1016/j.hydromet.2004.07.007 ◽

2004 ◽

Vol 75 (1-4) ◽

pp. 157-167 ◽

Cited By ~ 37

Author(s):

F. Pagnanelli ◽

G. Furlani ◽

P. Valentini ◽

F. Vegliò ◽

L. Toro

Keyword(s):

Nitric Acid ◽

Operating Conditions ◽

Low Grade ◽

Manganese Ores

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Direct Observation of Crystalline Ordering In Naturally Graphitized Carbon Produced by Low Grade Metamorphism

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100078377 ◽

1977 ◽

Vol 35 ◽

pp. 162-163

Author(s):

Thomas R. McKee ◽

Peter R. Buseck

Keyword(s):

Crystallite Size ◽

Sedimentary Rocks ◽

Carbonaceous Material ◽

Low Grade ◽

X Ray ◽

Graphitized Carbon ◽

Transmission Electron ◽

Heat Treated ◽

Commercial Carbon ◽

Metamorphic Zone

Sediments commonly contain organic material which appears as refractory carbonaceous material in metamorphosed sedimentary rocks. Grew and others have shown that relative carbon content, crystallite size, X-ray crystallinity and development of well-ordered graphite crystal structure of the carbonaceous material increases with increasing metamorphic grade. The graphitization process is irreversible and appears to be continous from the amorphous to the completely graphitized stage. The most dramatic chemical and crystallographic changes take place within the chlorite metamorphic zone.The detailed X-ray investigation of crystallite size and crystalline ordering is complex and can best be investigated by other means such as high resolution transmission electron microscopy (HRTEM). The natural graphitization series is similar to that for heat-treated commercial carbon blacks, which have been successfully studied by HRTEM (Ban and others).

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Ectodesmata as Revealed By Freeze-Etch Preparations of Plant Epidermal Cell Walls

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100072782 ◽

1973 ◽

Vol 31 ◽

pp. 468-469

Author(s):

N.C. Lyon ◽

W. C. Mueller

Keyword(s):

Electron Microscopy ◽

Acetic Acid ◽

Nitric Acid ◽

Oxalic Acid ◽

Light Microscopy ◽

Epidermal Cell ◽

Cell Walls ◽

Plant Viruses ◽

Plant Leaves ◽

Thin Sections

Schumacher and Halbsguth first demonstrated ectodesmata as pores or channels in the epidermal cell walls in haustoria of Cuscuta odorata L. by light microscopy in tissues fixed in a sublimate fixative (30% ethyl alcohol, 30 ml:glacial acetic acid, 10 ml: 65% nitric acid, 1 ml: 40% formaldehyde, 5 ml: oxalic acid, 2 g: mecuric chloride to saturation 2-3 g). Other workers have published electron micrographs of structures transversing the outer epidermal cell in thin sections of plant leaves that have been interpreted as ectodesmata. Such structures are evident following treatment with Hg++ or Ag+ salts and are only rarely observed by electron microscopy. If ectodesmata exist without such treatment, and are not artefacts, they would afford natural pathways of entry for applied foliar solutions and plant viruses.

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