IJCPE Vol.11 No.2 (June 2010) 

 

 

 
Iraqi Journal of Chemical and Petroleum Engineering 

 Vol.11 No.2 (June2010) 49-54 

ISSN: 1997-4884 

 

 

 

 

Study on Vanadium Recovery from Spent Catalyst Used in the Manufacture of 

Sulfuric Acid 
  Khalid M. Mousa and Safa K. Kouba  

Chemical engineering Department/Collage of engineering/ University of Nahrain 

   

Abstract 

Spent catalysts for sulfuric acid production have large amount of vanadium and due to environmental authority it is 

required to reduce the vanadium contain of the spent catalyst. Experimental investigation was conducted to study the 

vanadium recovery from spent catalyst via leaching process using sodium hydroxide to study the effect of process 

variables (temperatures, sodium hydroxide molarities, leaching time and particle size) on vanadium recovery.  The effect 

of process variables (temperature, particle size,molarities of sodium hydroxide and leaching time) on the percentages of 

vanadium recovery were investigated  and discussed .It was found that the percentage of vanadium recovery increased 

with increasing temperature up to 100  , increasing sodium hydroxide molarity from 2 to 4M, increasing leaching 

time, decreasing particle size from mesh 150, 100 and 65. A complete vanadium recovery was achieved at the following 

conditions: temperature (100˚c), particle size (150 mesh ) molarity of Na OH(4 molar) and leaching time(5 h). 

Key words: vanadium, spent catalysts, sulfuric acid 

_____________________________________________________________________________________________

Introduction 

      Vanadium is employed for the manufacture of a 

variety of vanadium compounds. Vanadium compounds 

have been found effective for catalyzing both organic 

oxidation and reduction. The oxides of vanadium have 

found many applications as catalysts especially in vapor-

phase reductions. Vanadium pentoxide is the most 

common commercial form of vanadium. It can be used as 

a dye and color-fixer, and it's used as a catalyst in the 

production of sulfuric acid by Contact Process. 
Catalysts based on vanadium pentoxide are widely used 

in the conversion of naphthalene to phthalic anhydride. 

Vanadium is also used as catalyst in the process of CO₂  
removal from the gas mixture in ammonia synthesis West 

[1]. Haoran  et al. ,[ 2]; studied recovery of  vanadium 

from clay vanadium mineral using an acid leaching 

method 

References and further reading may be available for this 

article. To view references and further reading you must 

purchase this article.. A technique is including direct acid 

leaching.  Stas et al., [3]  studied  the recovery of 

vanadium, nickel and molybdenum from fly ashes 

produced from heavy oil-fired electrical power station 

using two stages leaching process which consisted  of an 

alkaline leaching to dissolve vanadium and molybdenum 

followed by sulfuric acid leaching to recover nickel. 

Lozano, and Godínez ,[4 ] studied  the solvent extraction 

of Vanadium in sulphate media using primary amine and 

tertiary amine  dissolved in kerosene has been carried out. 

Luis and Cury ,[5 ] studied  the catalyst leaching in order 

to reduce its vanadium content so that it can be safely 

disposed. Factorial experimental design was used and the 

process variables studied were particle size, temperature, 

acid concentration and agitation intensity. Results 

showed strong dependency between remaining vanadium 

content and particle size. Temperature has shown lesser 

influence. The latter indicates an intra particle diffusion 

controlled process. Conventional method for recovering 

vanadium from vanadium containing ores was studied by 

Hansen, [6]. This method included as an initial step the 

roasting of the vanadium ore with a sodium salt to form 

roasted products which contain sodium vanadate in solid 

form. The roasted material was then cooled, crushed, 

ground and water leached in agitation leach tank in a 

conventional manner. The solubilized sodium vanadate in 

solution was recovered from the solids through 

University of Baghdad 

College of Engineering 
Iraqi Journal of Chemical 

and Petroleum Engineering 

 

http://en.wikipedia.org/wiki/Vanadium(V)_oxide
http://en.wikipedia.org/wiki/Vanadium(V)_oxide
http://en.wikipedia.org/wiki/Vanadium(V)_oxide
http://en.wikipedia.org/wiki/Vanadium(V)_oxide
http://en.wikipedia.org/wiki/Vanadium(V)_oxide
http://www.sciencedirect.com/science?_ob=ArticleURL&_udi=B82XW-4SJYX8S-3&_user=10&_coverDate=04%2F30%2F2008&_rdoc=1&_fmt=full&_orig=search&_cdi=33041&_sort=d&_docanchor=&view=c&_acct=C000050221&_version=1&_urlVersion=0&_userid=10&md5=4ec626f7fc44c138d171479f03f33a26


Study on Vanadium Recovery from Spent Catalyst Used in the Manufacture of Sulfuric Acid 
 

IJCPE Vol.11 No.2 (June 2010) 
 

50 

convential solid-liquid separation such as filtration or 

counter current decantation. Jassim,[7]   used a solvent 

extraction technique as a separation method to separate a 

vanadium from the leach solution of the ashes of burned 

fuel oil at Electrical Power Station  . Tributyl phosphate 

(TBP) was used as an extracting agent through mixer-

settler batteries. Some Parameters, which influenced 

vanadium extraction, were studied in detail, such as 

chloride ion concentration and the acidity of the mother 

solution, in addition to the number of extraction, stripping 

stage and phase ratios.  Mousa [8 ]  recovered vanadium 

from scale residues of oil-fired power  stations  by 

alkaline leaching method using sodium hydroxide 

solution . Spent catalysts for sulfuric acid production 

have large amount of vanadium and due to environmental 

authority it is required to reduce the vanadium contain of 

the spent catalyst[ Khorfan et al. , [9]  studied  the  

recovery of vanadium pentoxide from spent sulfuric acid 

catalysts ,using a three-step process involving acid 

leaching, oxidation and precipitation. Several different 

acids were used in the leaching, sulfuric acid was used in 

various concentrations, solid to liquid ratios, stirring 

times and temperatures. A high solid/liquid ratio in the 

leaching stage was used to obtain high concentration of 

vanadium pent oxide and low acid consumption that 

allowed direct precipitation without the use of extraction 

by rather expensive organic solvents. Sodium carbonate 

solution of one mole/liter concentration was used in the 

precipitation stage.  Sulfuric acid was found to be the best 

leaching solution.  

The aim of this work is to study the possibilities of 

vanadium recovery from spent catalyst used via leaching 

process using sodium hydroxide due to selectivity of 

sodium hydroxide to vanadium, and study the factures 

affecting the leaching process.   

Experimental Apparatus 
 

Experiments were carried out in 1 litter glass reactor, the 

diameter of glass reactor was 12cm and the height was 10 

cm applying  on  heating mantle with thermostat      and a 

mixer  consisted of stainless steel shaft, screwed with 

four pitched turbine blades  impeller , the diameter of 
impeller was 4 cm. The stirrer rotated by means of an 

electrical motor coupled to variable resistor to achieve 

600 rpm . 

A schematic diagram of the reactor system is show in 

Fig. 1. 

 

 
 

Fig. 1 A schematic Diagram of the Reactor system 

 

Experimental procedure 

The sample of  spent catalyst used in this experimental 

procedures was obtained from (Al-Sadra Company in the 

west of Baghdad)  taken randomly, grinded in laboratory ball 

mill and sieved by means of laboratory sieve supplied by 

Retsch company  to obtain particle size (150 mesh=104 µm 

,100 mesh=147 µm and 65 mesh=208 µm ). Sodium 

hydroxide as applet supplied by BDH Company (98% ) was 

used due its selectivity of vanadium. The required (2-4) 

molar solution of sodium hydroxide was prepared in the 

experimental tank as fallow. 

 

 
Molar = mole / litter 

   of 

NaOH 

 

The solution was then heated to the desired temperature (60-

100ºC) while stirrer at 600 rpm, the rpm was achieved by 

means of variance coupled with motor .100 gm of spent 

catalyst with particle size in the  rang (mesh 150 to 65) was 

added to the aqueous solution of sodium hydroxide in each 

run .The reaction as follow. 

          

 

 

 



  Khalid M. Mousa and Safa K. Kouba  
 

 

IJCPE Vol.11 No.2 (June 2010) 51 

 After the desired time (1-5 hr) the solution was filtered to 

remove the unreacted vanadium and impurities. 

A fixed volume of 500 ml was used for all experiments.  The 

block diagram of Fig. 2 shows the processes. Solid samples 

of the powder stock, which was used in this work were 

analyzed for vanadium content and the average percentage 

was found to be (37 %). This value was used in the 

calculation of vanadium fraction recovery for each 

experiment. 

Samples of solutions from all experiments were analyzed for 

vanadium by means of Atomic Absorption spectrometry at 

the analytical laboratory of Ibn Cina Company.   

 

 
 

 

 

Fig.2. Experimental Procedure Block Diagram 

 

 

 

 

 

 

 

 

Results and Discussion 
The effect of temperature on vanadium recovery at 

different molarity at a given mesh size is shown in 

figures 3 and 4. 

Observing these figures it can be shown that 

increasing the temperature will increase the 

vanadium recovery, the temperature influences the 

vanadium recovery in number of ways. Firstly as 

the temperature increases the mobility of the 

molecules will increase due to more energy gain, 

secondly the effective diffusivity increases with the 

increase in the temperature. This coincides with the 

definition of the diffusivity.  

The main resistances to leaching are: kinetic of the 

process, intra-particle mass transfer and mass 

transfer from particle surface to surrounding. The 

chemical step is usually much more temperature-

sensitive than the physical steps. Levenspiel,[10]. 

Since the change in temperature affected the 

fraction recovery one can say that the chemical 

reaction step is dominate. 

Comparing with the results of Luis and Cury [5] 

reveals that the leaching velocity of residual 

vanadium content influenced by temperature where 

tested values from 25 to 55˚c,where vanadium 

recovery was 1310 ppm at( 35 mesh size ,25˚c and 

1% sulfuric acid concentration),while 1190 ppm at 

(35 mesh size ,55˚c and 1% sulfuric acid).  Khorfan 

et. al.[9] showed that the temperature affects the 

vanadium recovery up to 80˚c, above this value no 

effected was noted.    

 

Fig. 3 Effect of temperature on vanadium fraction 

recovery at different time for 5molar and 150 mish size 

 

 

 

 

 

 

 



Study on Vanadium Recovery from Spent Catalyst Used in the Manufacture of Sulfuric Acid 
 

IJCPE Vol.11 No.2 (June 2010) 
 

52 

 

 

 

 
 

Fig. 4 Effect of temperature on vanadium fraction 

recovery at different time for 3 molar and 150 mish sizes 
 

 

The effect of particle size on vanadium recovery at 

different temperature at a given time is shown in Fig 5. In 

this figure it can be seen that the fraction recovery 

increase as the particle size decrease (increasing mesh 

size). 

    The particle size influences the fraction recovery in a 

number of ways. The smaller the size is the greater 

interfacial area between the solid and liquid, the rate of 

reaction and the rate of transfer of material are higher. A 

reduction in particle size usually results in a decrease in 

the average time of passage of solvent from the surface to 

the interior of the particle and decrease the average time 

of passage of solvent from the surface to the interior of 

the particle and decrease the average time of passage of 

solute molecules from the dissolving point in the interior 

of solid particle to the surface of the particle ,Rickles,[11] 

.The effect of NaOH molarity on vanadium fraction 

recovery is shown in Fig.6   The figure shows that 

vanadium recovery increase as the molarity of NaOH 

increases. Comparing with result of Luis &Cury,[5] on 

which, the results shows that the vanadium  recovery 

does not effected by sulfuric acid concentration,  where 

the vanadium recovery constant at 1110 ppm  in spite of 

changing the concentration from 1% to 10% while the 

other conditions are constant(65 mish size and 25˚c ). 

 

 

 

 

 

 

 

 

 

 

 

 

 

Fig 5 Effect of temperature on vanadium fraction 

recovery for 4 molar and 5 h 

 

 

Fig. 6:  Effect of NaOH molarity on vanadium fraction 

recovery for 5 h and 150 mish size. 

 

Figures 7, 8 and9 shows the plots of fraction of vanadium 

recovery versus time for different temperatures and a 

given mesh size and NaOH molarity. It is clear from 
these figures that the best leaching time which lead to 

maximum recovery of vanadium is greatly dependant on 

the specific conditions of test i.e particle size, molarity of 

NaOH and temperature of test.  Examination of figure 6 

shows that the maximum fraction recovery was 150 mesh 

size and 4 molar NaOH, where the best leaching time was 

found to be 5 h at 100˚c.  

 Khorfan et al,[9] showed that the leaching was carried 

out by varying the time of mixing from 10 min to 4 hours 

while keeping other conditions constant (T = 100 

◦C,solid/liquid = 1/10 g/ml, sulfuric acid 15% v/v). The 

efficiency was constant after 30min so it is enough to fix 

the mixing time at one hour for other experiments. 

 



  Khalid M. Mousa and Safa K. Kouba  
 

 

IJCPE Vol.11 No.2 (June 2010) 53 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Fig. 7   effect of time on vanadium fraction recovery 

for 65 mesh size and 4 molar NaOH 

 

 
 

Fig. 8 effect of time on vanadium fraction recovery at 

different temperatures for 100 mesh size and 4 molar 

NaOH. 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Fig. 9  effect of time on vanadium fraction recovery 

for 150 mesh size and 4 molar NaOH 

 

 

Conclusions: 
 

1.From the present investigation it was 

concluded that the fraction of  vanadium 

recovery increasing with increasing of 

temperature ,NaOH molarity ,leaching time 

and decreasing with particle size 

increasing.: 

 

2.The optimum leaching time depended 

greatly on specific conditions of test 

;temperature, particle size and NaOH 

molarity. 

 

 

3.The selectivity of  NaOH solution for the 

recovery of  vanadium from spent catalyst 

was excellent. 

 

4.A complete vanadium recovery was 

achieved at the following conditions: 

temperature (100˚c), partical size( 150 

mesh), molarity of NaOH(4 molar) and 

leaching time(5 h).  

                                                                              

References: 

1-West , R.C. CRC handbook of chemistry and physics , 

67
th

 ed., Boca Raton, Florida, CRC Press1987 

2-Haron etl "vanadium recovery from day 

vanadium mineral using an acid leaching method" 

,civil and environment engineering school 

,University of science &technology Beijing, 

received  2007 

 

3-Stas Jamal, Ajaj Dahdouh , Omar Al-chayah, 

"Recovery of Vanadium, Nickel and Molybdenum 

from fly ash of heavy oil-fired electrical power 

station” , Department of Chemistry, Atomic Energy 

Commission„ P.O.Box 6091 Damascus, Syria  

2006. 

4-Lozano L. J.
, 

and C. Godínez "Comparative 

study of solvent extraction of vanadium from 

sulphate solutions by primene 81R and alamine 

336”,Department of Chemical and Environmental 

Engineering, Polytechnic University of Cartagena, 

Campus Muralla del Mar S/N, 30202, Paseo 

Alfonso XIII, 50, Cartagena 30203, Spain,  29 

October 2002. 

5-Luis etl . "vanadium recovery by leaching in 

spent catalysts for sulfuric acid 



Study on Vanadium Recovery from Spent Catalyst Used in the Manufacture of Sulfuric Acid 
 

IJCPE Vol.11 No.2 (June 2010) 
 

54 

production",science&technology. V.8 no.16.p.85-

90, 2000 
6-Hansen; Donald J. (Lewiston, NY), Goddard; 

John B. (Grand Island, NY), Malacarne; Oreste J. 

(Grand Junction, CO)," Method for recovering 

vanadium from vanadium-containing ore "

,No.6/858,917,  May 2, 1986 

 

7-Jasim Salh Al-Deen , study of the Extraction of 

Vanadium by TBP M.Sc. Anbar University1998. 

 

8-Kh. M.Mousa,"Study Of Leaching On Recovery 

Of  Vanadium From Scale Residues Of Oil-Fired 

Power Stations”, Baghdad University / Department 

Of Chemical Engineering, 1999 . 

9-Khorfan S., A. Wahoud,  and  Y. Reda, 

“Recovery of Vanadium Pentoxide from Spent 

Catalyst Used in the Manufacture of Sulfuric 

Acid”,Atomic Energy Commission 

Hydrometallurgy Office, Damascus, Dec. 10 

(2002). 

10- Levenspiel, “Chemical Reaction Engineering", 

3rd edition, John-Wiley and Sons Inc., New York 

(1999). 

 

11-Rickles,N., Chem.Eng., March (1965). 

 

 

 

 

 

 

 

 الخالصة
 

 

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    . يحهىل هيذسوكسيذ انصىديىوبىاسطتانكبشيتيك 

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