1. STUDY BY MÖSSBAUER SPECTROSCOPY OF THE MATERIAL
FROM OSHNO HILL, DISTRICT OF CHAVIN DE PARIARCA,
REGION OF HUANUCO, PERU
A. Bustamante1, D. Lovera2, R. Quille1, A. V. Arias2 and J. Quiñones2
1
Laboratorio de Cerámicos y Nanomateriales. Facultad de Ciencias Físicas, Universidad Nacional Mayor
de San Marcos, Lima, Perú.
2
Facultad de Ingeniería Geológica, Minera, Metalúrgica y Geográfica, Universidad Nacional Mayor de
San Marcos, Lima, Perú.
Abstract
Prospective studies developed in the Area of the Marañón Basin in Perú show us a type of so-called
Complex Regional Geology of the Marañón consisting of metal ores of copper, silver, gold schist and
gneiss in contact with intrusive, as well as minerals nickel, cobalt, titanium, platinum, among others. The
sample was collected on the hill OSHNO which is located in the District of Chavín de Pariarca,
Huamalies Province, Region Huanuco, Peru. The analysis by X-ray diffraction of the sample OSHNO
indicates the presence of the lepidocrocite (-FeOOH) and goethite (-FeOOH). The Mössbauer spectrum
(EM) at room temperature for OSHNO measure at high velocity does not show a magnetic component but
shows a double widening, proceeding to measure at low velocity. A good fit spectrum include the
presence of two doublets. The first doublet has hyperfine parameters of IS=0.367mm/s, DQ=0.51mm/s
and =0.37mm/s and corresponds to the presence of the lepidocrocite and the second doublet has a
IS=0.366mm/s, DQ=0.48mm/s and =0.98mm/s, the line width is widened and corresponds to smaller
particles of hydroxides than 100Å in superparamagnetic state. The EM at the temperature of liquid helium
shows a sextet of line width widened and was fitted with a distribution of fields confirming the presence
of goethite and lepidocrocite (with magnetic field average of 49.32T and 44.0T respectively). Chemical
analysis indicated the presence of Cu, Zn, As, Mn and Ba as major elements and Cr, V, W, Sr, Cd, Co,
Ag, La, Sc, Sn, Fe and Ni as minor elements. The sample of OSHNO as metallic powder grain is of interest
to small and medium steel industry.
Keywords: Goethite, Lepidocrocite, Mössbauer Spectroscopy.
1. Introduction
The studied area corresponds to the Marañón Basin in Peru, showing a kind of Regional
Geology named Complejo Marañón, consisting of metal minerals such as Copper, Silver
and Gold in schists (which are rocks that can be easily split in thin layers), consisting of a
group of medium-grade metamorphic rocks mainly prominent for the preponderance of
laminate minerals such as mica, chlorite, talc, hornblende, graphite, and others in contact
with intrusions, as well as with other nickel, cobalt, titanium, platinum minerals, among
others.
The sample was collected at the OSHNO hill, which is located in the Chavin de Pariarca
District, Province of Huamalies, Huanuco Region, Peru, as described on the maps in
Figures 1 and 2, where the sample minted is shown. The characterization of minerals of
this area is made by Instrumental Techniques: Optical Microscope, Mössbauer
spectroscopy Analysis, Multi-elemental Chemical analysis, allow us to check the
presence of metalic minerals in the Marañón Complex, as well as the presence of Iron
oxide with a magnetization grade that indicates the presence of metals in areas where
samples were taken from.
The metallurgy tests carried out indicate a good metallurgy recovery of concentrate
obtained of Chalcopyrite mineral, which means a good economic possibility for the
Marañón Basin [1].

2. Figure 1. Location of the hill Oshno
Figure 2. Oshno part of the hill where the sample is collected
2. Experimental
In the Laboratory of Extractive Metallurgy - UNMSM proceeded to develop metallurgical
processes and operations commissioned: crushing, grinding and sifting to take a size
suitable for the chemical and physical characterization.

3. The X-ray powder diffraction patterns were recorded on BRUKER D8 Focus using a
monocromador of graphite and using Cu-K1,2 radiations (=1.5460 Å) in the range 8º to
80º with step 0.02º. The chemical composition was determined by inductively couples
plasma optical emission spectroscopy (ICP-OES) using the method ICP-40B that consist
in multi-acid (4 acid) digestions that is a combination of HCl (hydrochloric acid), HNO3
(nitric acid), HF (hydrofluoric acid) and HClO4 (perchloric acid). Because hydrofluoric
acid breaks down silicates, these digestions are often referred to as “near- total
digestions”. There can be a loss of volatiles during digestion (e.g. B, As, Pb, Ge, Sb).
Multi-acid digestion is a very effective dissolution procedure for a large number of
mineral species and is suitable for a wide range of elements.
Mössbauer spectra were recorded in transmission geometry using a constant acceleration
spectrometer and a 512 multichannel analyser. The source is a 57Co in Rh matrix. Spectra
were recorded on all samples at 300K. Isomer shifts are given relative to the centroid of
the spectrum of an absorbedor of -Fe at room temperature. Spectra were analysed by
least-squares fits using lorentzian line shape. All fitting procedures were performed with
the NORMOS program [2].
3. Results and discussion
3.1 X-ray difraction
The X-ray diffraction (XRD) pattern is showed in the Figure 3 and the analysis indicates
the presence of two mineralogical phases such as de la lepidocrocite (-FeOOH ASTM
74-1877) y la goethite (-FeOOH ASTM 02-0273).
80
G Goethite -FeOOH 02 0273
70 L Lepidocrocite -FeOOH 74 1877
Intensity Normalized (u.a.)
60 G
L
50
40 L L G L
G
G GG G
G L
30 G GL
L G
G
20
10
0
10 15 20 25 30 35 40 45 50 55 60 65 70 75 80
2
Figure 3. X-ray difracction of Oshno sample.
3.2 Chemical analysis
The chemical analysis is sowed in Table 1, indicates that the presence of major elements
Cu, Zn, As, Mn y Ba and Cr, V, W, Sr, Cd, Co, Ag, La, Sc, Sn, Fe y Ni as minor elements
(Certificate Nº 42876 of SGS company).
Table 1. Chemical analysis of the sample Oshno.

4. Major elements (ppm)
Cu Zn As Mn Ba
968 3996 367 1118 282
Minor elements (ppm)
Cr V W Sr Cd Co Ag La Sc Sn Ni Fe
92 66 34 197,8 23 23 6,8 38,7 12,3 24 18 7,39
3.3 Mössbauer spectroscopy
The Mössbauer spectrum (ME) at room temperature of the sample from hill OSHNO at
high velocity does not shows any magnetic component but show a broadened doublet,
proceeding to measure at low velocity (Figure 3). A good fit spectrum include the
presence of two doublets. The first doublet have hyperfine parameters of IS=0.367mm/s,
DQ=0.51mm/s and =0.37mm/s and corresponds to the presence of the lepidocrocite [3]
and the second doublet has IS=0.366mm/s, DQ=0.98mm/s and =0.48mm/s and the line
width widened and corresponds to particles of oxides or hydroxides lower than 100Å in
superparamagnetic state. See table number 2.
Transmisión Relativa (%)
5%
-3 -2 -1 0 1 2 3
Velocidad (mm/s)
Figure 3. Mössbauer spectra at RT.
Table 2.-Hyperfine parameters for fitted Mössbauer spectra.  is the isomer shift relative to  iron,  is
the quadrupole splitting, 2 is the quadrupole shifts,  is the line width, and A is the spectral fraction as
obtained from the fit. Bhf is the hyperfine field.
 Area Fe  o 2 Bhf
(mm/s) (%) (mm/s) (mm/s) (T)
RT
Lepidocrocite 0.37 53 0.367 0.51
Goethite 0.48 47 0.366 0.98
4.2K
Lepidocrocite 0.35 0.356 -0.102 44.00
Goethite 0.35 0.356 -0.102 49.32
The ME at the temperature of liquid helium in zero external magnetic field shows the
broadened sextet which was fitted using a hyperfine field distributions with the average
isomer shift of 0.356m/s and quadrupole shift closed to zero, confirming the presence of
goethite (-FeOOH with magnetic field average of 49.32T) and the lepidocrocite (-
FeOOH) with field half of 44.0T, showed in the Figure 4.

5. 1.02
1.01 P(BHf)
A
0,05
1.00
P
0,04
Relative transmission (u.a.)
0.99
0.98
0,03
0.97 0,02
0.96 0,01
0.95 0,00
0 5 10 15 20 25 30 35 40 45 50 55 60
-10 -8 -6 -4 -2 0 2 4 6 8 10
Hyperfine field (T)
Velocity (mm/s)
Figure 4. Mössbauer spectra at 4.2K and hyperfine-field (Bhf) distributions.
The sample of OSHNO as metallic powder grain is of interest to small and medium steel
industry.
Acknowledgements
A.B.D thanks to the UNMSM for supporting this research, through the SEGUSM system
and Dra. Rosa B Scorzelli from CBPF by the measurement at helio temperature.
References
1.- D. Lovera, A. Bustamante, P. Gagliuffi, J. Quiñones, L. Puente, L. Gaudencio, J.
Diego, A. Romero. Revista del Instituto de Investigación FIGMMG Vol 8 Nº 16
(2005) 44-50.
2.- Brand, R.A.: Normos Programs. Duisburg Universiy (1989).
3.- Mössbauer Mineral Handbook, Editors J.G. Stevens, A.M. Khasanov, J.W. Miller, H.
Pollak, and Z. Li. Mössbauer Effect Data Center 2002.