The work presents an original method for titanium hydride production by hydrogenation and dehydrogenation of titanium waste in a specially designed for this purpose vacuum chamber. Laboratory quantities of titanium hydride were prepared using LaNi5 hydrogen accumulator as a source of pure hydrogen. Chemical, X-ray, DTA, TG and granulometric analysis of the obtained hydride were made. The analyses carried out in the temperature range, 680-1070 К, DTA, TG and mass-spectrometry analysis allowed determining the activation energy of decomposition of the obtained TiH2 which was approximately E = -135.5 kJ/mol and the standard enthalpy of formation ΔH = -140 kJ/mol

Jordan GEORGIEV

Lubomir ANESTIEV

Rositsa GAVRILOVA

Simona BEJAN

Yavor LUKARSKI

The Annals of “Dunarea de Jos” University of Galati Fascicle IX Metallurgy and Materials Science

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197 6
 
 
THE ANNALS OF “DUNAREA DE JOS” UNIVERSITY OF GALATI. 
FASCICLE IX. METALLURGY AND MATERIALS SCIENCE 
N0. 4 – 2010, ISSN 1453 – 083X 
 
 
 
 
 
INVESTIGATION OF TITANIUM HYDRIDE PRODUCED  
FROM TITANIUM WASTE 
 
Yavor LUKARSKI1, Jordan GEORGIEV1, Lubomir ANESTIEV1, 
Rositsa GAVRILOVA2, and Simona BEJAN3 
1Institute of Metal Science, Bulgarian Academy of Sciences, Sofia, Bulgaria 
2University of Chemical Technologies and Metallurgy, Sofia, Bulgaria 
3Politechnica University of Bucharest, Romania 
e-mail: lukarski@ims.bas.bg 
 
ABSTRACT 
 
 
The work presents an original method for titanium hydride production by 
hydrogenation and dehydrogenation of titanium waste in a specially designed for 
this purpose vacuum chamber. Laboratory quantities of titanium hydride were 
prepared using LaNi5 hydrogen accumulator as a source of pure hydrogen. 
Chemical, X-ray, DTA, TG and granulometric analysis of the obtained hydride were 
made. The analyses carried out in the temperature range, 680-1070 К, DTA, TG and 
mass-spectrometry analysis allowed determining the activation energy of 
decomposition of the obtained TiH2 which was approximately E= -135.5 kJ/mol and 
the standard enthalpy of formation ΔH= -140 kJ/mol. 
 
KEYWORDS: hydrogen, titanium waste, titanium hydride 
 
1. Introduction 
 
The use of titanium and titanium alloys grows by 
8-10% per year [1]. This also leads to increasing the 
amount of produced titanium wastes. For this reason, 
the problem of utilizing these wastes comes to the 
fore. There are different methods for utilization but 
the recently most widely applied one is hydrogenation 
of titanium in the presence of hydrogen to titanium 
hydride (TiH2) formation. The latter represents grey-
black powder with molecular weight of 49.53-49.90 
g/mol, specific density of 3.75 g/cm3 and hydrogen 
content within the range of 3.85-4.02 % (by weight). 
The results from the investigation on some 
characteristics of the titanium hydride produced by 
the team are given in this work. 
 
2. Methodology of the experiment 
 
The experiments were carried out using specially 
constructed equipment for this purpose [2]. Fig. 1  
shows the photo of this equipment. The main feature 
is the use of a hydrogen accumulator as a hydrogen 
source, which solves the problems with hydrogen 
utilization. 
The main elements of the equipment are: heating 
furnace, programmable thermoregulator, reaction 
chamber, vacuum system, hydrogen source, system 
for hydrogen feeding, system for temperature 
measurement, system for recording the pressure in the 
hydrogen accumulator and the reaction chamber, 
system for charging the hydrogen accumulator. 
The initial raw materials subjected to 
hydrogenation are shavings of pure titanium and 
titanium alloy. The chemical composition is obtained 
according to the ACP-AES method and is shown 
below: 
 
• Pure Ti: 0.081% Al, 0.0014% Mn, 0.0034% 
V; 
• Titanium alloy: 0.504% Al, 0.0065% Mn, 
0.0197% V. 
 
The experiments were carried out at three different 
temperatures of the furnace, adjusted by the 
thermoregulator–873, 923 and 973 K. The sequence 
of operation of this installation is as follows: 
The titanium crucible wastes in the form of 
briquettes and a thermocouple is placed in the reactor, 
which is closed hermetically under vacuum. Another 
thermocouple is placed in the zone of the crucible, 
which measures the temperature defined by the 
thermoregulator.  
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THE ANNALS OF “DUNAREA DE JOS” UNIVERSITY OF GALATI. 
FASCICLE IX. METALLURGY AND MATERIALS SCIENCE 
N0. 4 – 2010, ISSN 1453 – 083X 
 
 
 
The vacuum in the reactor is achieved by a 
vacuum pump with all turn-cocks closed. Then the 
intermediate cock to the vacuum pump is closed and 
the cock to the hydrogen accumulator is opened. 
 
 
 
Fig. 1. Installation for producing TiH2. 
 
Hot water is fed into the accumulator cylinder and 
the transfer of hydrogen to titanium is started. The 
furnace heater is switched on, the temperature regime 
of heating and soaking being preliminarily set by 
means of the programmable thermoregulator. The 
heating rate is 10°С/min. When reaching the 
maximum temperature, the feeding of hydrogen by 
the accumulator has ceased. The titanium 
hydrogenation reaction is started at a definite 
temperature and the pressure of hydrogen in the 
reactor is decreased. At the moment, when hydrogen 
pressure stops falling, a new portion of hydrogen is 
fed to the set pressure.  
The procedure is continued until hydrogen 
pressure remains unchanged after the consecutive 
feeding of hydrogen. This is an indication that the 
hydrogenation process is completed and the furnace is 
switched off.  
After cooling of the reaction zone to 50°С cold 
water is fed to the hydrogen accumulator in order to 
absorb the non-reacted hydrogen.  
For this purpose, the turn-cock of the accumulator 
is opened. 
After evacuating the hydrogen the turn-cock of the 
accumulator is closed, the reaction zone is subjected 
to vacuum and the reactor is filled with SO2 or argon 
to protect titanium hydride against combustion.  
The reactor is opened and the ready product is 
taken out. The change of the actual temperature in the 
reaction zone is shown in Fig. 2.  
The exothermal peaks of the titanium 
hydrogenation process are clearly outlined. 
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THE ANNALS OF “DUNAREA DE JOS” UNIVERSITY OF GALATI. 
FASCICLE IX. METALLURGY AND MATERIALS SCIENCE 
N0. 4 – 2010, ISSN 1453 – 083X 
 
 
 
0
100
200
300
400
500
600
700
800
900
0 3600 7200 10800 14400 18000 21600 25200
Time, [s]
T
em
pe
ra
tu
re
, [
o C
]
 
Fig. 2. Temperature change in the reaction zone. 
 
3. Results and analysis 
 
3.1. Granulometric analysis 
The performed granulometric analysis of the 
produced and ground titanium hydride shows that 
93.45 % of the product has a grain-size lower than 20 
µm. 
3.2. X-ray structural analysis 
Figure 3 shows the results from the X-ray 
structural analysis of a titanium hydride sample using 
a Bruker D8 Advance diffractometer.  
The only phase is TiH1,924. No lines of titanium are 
observed, which shows that practically the whole 
titanium quantity is bound into titanium hydride. 
 
Titanium Hydride
00-025-0982 (I) - Titanium Hydride - TiH1.924 - Y: 54.61 % - d x by: 1. - WL: 1.5406 - Cubic - a 4.44800 - b 4.44800 - c 4.44800 - alpha 90.000 - beta 90.000 - gamma 90.000 - Face-centered - Fm-3m (225) - 4 - 88.0024 - F5= 36(0
Operations: Background 1.000,1.000 | Import
File: TiH2-probaN8-2,367g.raw - Type: 2Th/Th locked - Start: 10.000 ° - End: 80.000 ° - Step: 0.040 ° - Step time: 1. s - Temp.: 25 °C (Room) - Time Started: 9 s - 2-Theta: 10.000 ° - Theta: 5.000 ° - Chi: 0.00 ° - Phi: 0.00 ° - X: 0.0 
Li
n 
(C
ou
nt
s)
0
100
200
300
400
2-Theta - Scale
10 20 30 40 50 60 70 8
 
Fig. 3. X-ray diagram of a titanium hydride sample. 
 
 
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THE ANNALS OF “DUNAREA DE JOS” UNIVERSITY OF GALATI. 
FASCICLE IX. METALLURGY AND MATERIALS SCIENCE 
N0. 4 – 2010, ISSN 1453 – 083X 
 
 
 
3.3. Thermal analysis 
Samples of the produced titanium hydride are 
subjected to thermal and mass-spectrometric analysis. 
It is performed by a DTA-analyzer LABSYS-evo, 
combined with a mass-spectrometer of the Setaram 
Company. The differential thermal analysis (DTA) is 
carried out for five heating rates of 5, 8, 10, 12 and 15 
K/min in argon atmosphere to a maximum 
temperature of 800°С. Figure 4 presents the obtained 
DTA-curves for 5 and 12K/min. The temperatures 
with local extremum – Tmаx, are determined for the 
five curves.  
They are processed according to the method of 
Kissinger [3] (the equation shown below) and the 
value of the activation energy of titanium hydride 
decomposition is determined from the slope of the 
straight lines in Fig. 5–E=-135.5 kJ/mol. Here β 
designates the heating rate, Е – the activation energy, 
R–the gas constant. 
 
 
-35
-30
-25
-20
-15
-10
-5
0
5
0 100 200 300 400 500 600 700 800 900
Temperature, [oC]
H
ea
t, 
[m
V
]
0.E+00
1.E-11
2.E-11
3.E-11
4.E-11
5.E-11
6.E-11
7.E-11
Pa
rt
ia
l p
re
ss
ur
e 
of
 H
yd
ro
ge
n,
 [A
]
Heat Hydrogen pressure
a 
-70
-60
-50
-40
-30
-20
-10
0
0 100 200 300 400 500 600 700 800 900
Temperature, [oC]
H
ea
t, 
[m
V
]
0.E+00
2.E-11
4.E-11
6.E-11
8.E-11
1.E-10
1.E-10
1.E-10
Pa
rt
ia
l p
re
ss
ur
e 
of
 H
yd
ro
ge
n,
 [A
]
Heat Hydogen pressure.
b 
Fig. 4 (a, b). DTA curves of TiН2 decomposition for different heating rates, 
(a) -5 K/min, (b) - 12 K/min. 
1.0E-08
1.0E-07
1.07 1.08 1.09 1.1 1.11 1.12 1.13 1.14 1.15
1000/Tm, [K
-1]
β/
R
.T
m
2
 
Fig. 5. Kissinger plot of the data for Тmax obtained for the DTA curves. 
 
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FO N D ATĂ
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THE ANNALS OF “DUNAREA DE JOS” UNIVERSITY OF GALATI. 
FASCICLE IX. METALLURGY AND MATERIALS SCIENCE 
N0. 4 – 2010, ISSN 1453 – 083X 
 
 
 
4. Conclusion 
 
A laboratory installation has been developed for 
producing titanium hydride by treatment of titanium 
wastes with hydrogen and laboratory quantities of the 
hydride have been obtained. An original method is 
applied for feeding the hydrogen from a hydrogen 
accumulator. The granulometric composition of 
titanium hydride has been determined. The X-ray 
structural analysis shows the existence of only the 
TiH1,924 phase. 
The carried out thermal analysis provided the 
possibility of determining also the enthalpy of the 
produced titanium hydride. The value of standard 
enthalpy of formation obtained by us -140 kJ/mol is in 
agreement with the value found by other authors [4-
6]. On the basis of the results from thermal, 
thermogravimetric and mass-spectroscopic analysis of 
titanium hydride samples the activation energy of 
decomposition of the produced titanium hydride is 
determined. It is approximately Е= -135.5 kJ/mol. 
 
Acknowledgment 
 
The present work is supported by Project BRS-
11/2007, financed by the National Science Fund of 
the Ministry of Education, Youth and Science of 
Republic of Bulgaria. 
 
References 
 
[1]. www.roskill.com. 
[2]. Georgiev, J., Y. Lukarski. Laboratory Installation for 
Producing TiH2 by Hydrogen. Processing. 5th Congress of the 
Society of Metallurgists of Macedonia with International 
Participation, Sept. 17-20, 2008, Ohrid, Macedonia, CD ISBN 978-
9989-9571-4-7, M8-02-E. 
[3]. Kissinger, H. E., Reaction kinetics in differential thermal 
analysis, Anal. Chem. 29 (1957) 1702-1706. 
[4]. Jing-wei Zhao, Hua Ding, Xue-feng Tian, Wen-juan Zhao 
and Hong-liang Hou Chin. J. Chem. Phys. 21 (2008) 569-574. 
[5]. E. Koenigsberger, G.Eriksson and W. A. Oates, Journal of 
alloys and Compounds, 299 (2000) 148-152. 
[6]. A. San-Martin and F. D. Manchester, Bulletin of Alloy Phase 
Diagrams, 8(1) (1987) 30-42. 
 
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Investigation of Titanium Hydride Produced from Titanium Waste

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Investigation of Titanium Hydride Produced from Titanium Waste

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