Stripping Of Molybdenum Research Articles

Liquid-liquid extraction of molybdenum(VI) using aqueous two-phase systems (ATPS) consisting of polyethylene glycol (PEG) and sodium, ammonium and copper(II) salts: Comparison with conventional solvent extraction

In this work, the stripping of molybdenum from aqueous two-phase aqueous systems (ATPS) formed by a mixture of polyethylene glycol (PEG) 4000, salt and water was studied at different operational conditions of pH (7, 8 and 9) and temperature (308.15, 323.15 and 338.15 K), using two molybdenum salts (Na2MoO4 and (NH4)6Mo7O24). These salts were used for the experimental tests of extraction and stripping of the two-phase aqueous system of PEG 4000, CuSO4 and water, to evaluate the best percentage of stripping using different stripping agents: NaOH, Na2CO3, CuSO4 and a mixture of (NH4)2SO4 and NH4OH (Khayati et al., 2011). According to the results, the best stripping agent was the 20% (NH4)2SO4 solution as phase former plus 25% NH4OH as pH modifier. The experimental results indicate that the increase in temperature is directly proportional to the percentage of stripping. For the system of PEG 4000, CuSO4, water, Na2MoO4, (NH4)2SO4 and NH4OH system (ATPS 1) the percentage of stripping was 96.3%. In the case of PEG 4000, CuSO4, (NH4)6Mo7O24, water (NH4)2SO4 and NH4OH (ATPS 2) the stripping was 99%, these being the maximum values of stripping at pH = 2 and T = 308.15 K.It was determined that for ATPS 1, as the pH increases the stripping efficiency tends to decrease, while as the pH increases in ATPS 2, the stripping efficiency increases; this behavior is attributed to the hydration energy of the ions. Finally, a pre-feasibility study of the studied processes, ATPS 1, ATPS 2 and traditional solvent extraction (SX), was carried out, which included calculation of the profit factors.

Reaction engineering of continuous crystallization of β-ammonium tetramolybdate in concentric structure reactor and its application

Abstract β-ammonium tetramolybdate [β-(NH4)2Mo4O13] is an important product of molybdenum metallurgy because of its uniform crystal structure and excellent thermal stability. The yield of molybdenum strip produced with β-(NH4)2Mo4O13 as raw material and various processing properties have been significantly improved. However, the crystallization process of β-(NH4)2Mo4O13 is very complex, including neutralization, polymerization, nucleation, and crystal growth stages, resulting in a variety of polymerization morphology. In this work, a concentric structure reactor was used to segment these stages with directional regulation of each stage. Residence time distribution (RTD) was used to evaluate the simulation of flow field characteristics in the concentric structure reactor. Determination of the influence of inlet-outlet positions, size and position of paddle, and baffle setting on the fluid behavior in a single tank suggested measures to improve the abnormal flow condition and reduce the dead zone volume fraction. In the concentric structure reactor, the dead zone volume fraction was only 2.36% when the clapboards were arranged alternately in an up-down design, using an inlet flow rate of 100 mL/min. β-(NH4)2Mo4O13 was prepared continuously by adding aqueous ammonia and product slurry for crystallization in the concentric structure reactor.

Environmental friendly approach for selective extraction and recovery of molybdenum (Mo) from a sulphate mediated spent Ni–Mo/Al2O3 catalyst baked leach liquor

Solvent extraction separation of molybdenum (Mo) from the sulphate mediated leach solution bearing Aluminium (Al) and Nickel (Ni) was carried out using N-Methyl-N, N, N-tri-octyl-ammonium chloride. Extensive investigation for extraction study molybdenum in the function of time, Eq.pH, extractant concentration, diluents, temperature, strip solution concentration and phase ratio(A:O) for both extraction and stripping was examined to attain a suitable condition on its selective and enriched extraction. As per the equilibrium study and increasing trend of Eq. pH (pHe) at the correspondence initial pH, it was apparent about association of 1 mol of H+ ion during extraction which with was further supported on extraction of Mo as HMO4- at the pHe of 3.48. The association of 1 mol of exrractant during the extraction of Mo was also well evident from the slope analysis study. This indicates about anion exchange phenomenon due to Cl− ion of the N-Methyl-N, N, N-tri-octyl-ammonium chloride (extractant) with HMo4− from aqueous phase during complex formation reaction. The FTIR of the organic sample before and after extraction further confirms in support of the complex formation of the molybdenum with the extractant during extraction. The extraction isotherm was constructed at optmum extraction condition: pHe of 3.48 with 0.08M N-Methyl-N, N, N-tri-octyl-ammonium chloride predicts on need of 2-counter current stages for quantitative extraction of Mo at A:O = 3:1. To investigate the regeneration behaviour of adopted extractant along with enriched stripping of molybdenum, ammoniacal reagents were used in stripping study. The stripping of Mo showed promising and efficient using the mixture of the ammoniacal reagents (NH4OH + NH4Cl) over the either of the solo reagents. The stripping Mc-Cabe Thiele diagram was plotted using 2M NH4OH + NH4Cl ensures on quantitative stripping of Mo at SO: SS = 2:1 at 2 no. of stages. Both extraction and stripping isotherm results are validated at predicted isotherm conditions by 6-cycles counter current simulation (CCS) study leading to obtain 6-fold enrichment of Mo in stripped solution phase. The subsequent enriched content of Mo (∼60 g/L) in stripped solution phase was precipitated out followed by calcinations 400 °C to obtain a high pure MoO3. The recovered calcined product as MoO3 resulted through the proposed processing approach was as ascertained from XRD analysis.

Molybdenum strip test experiments and simulations at various temperatures to determine friction coefficients

The aim of the presented study was to perform the strip test of 0.5 mm thick molybdenum strip specimens by various simulated drawbead heights from 2 mm up to 6 mm and various temperatures from 20 °C up to 320 °C to obtain friction coefficients between the molybdenum strip and steel cylinders built-in the developed test device simulating the drawbead. The friction coefficients between the dry and lubricated molybdenum strip and the steel cylinders simulating the drawbeads were obtained by changing its value in the bilinear friction model and matching the holder drawing force and the drawbead restraint force curves achieved during the tests and the simulations. The increasing temperature of molybdenum strip led to reduced holder drawing force and drawbead restraint force and increased friction coefficient because of the decrease of molybdenum strip yield strength and the increase of surface contact between molybdenum sheet and the testing tool at elevated temperature.

Separation of V (V) and Mo (VI) in roasting-water leaching solution of spent hydrodesulfurization catalyst by co-extraction using P507 - N235 extractant

P507 (2-ethylhexyl phosphonic acid mono-2-ethylhexyl ester) - N235 (trioctyl tertiary amine), diluted with kerosene, was used for separation of vanadium (V) and molybdenum (VI) from roasting-water leaching solution generated by spent hydrodesulfurization catalyst. Due to the leach solutions contain impurities like aluminum (Al) and magnesium (Mg), the effects of various conditions on the separation of V (V), Mo (VI), Al and Mg were investigated. Upon using 20% P507 - N235 (P507: N235 = 2:1) (v/v) as the extractant, kerosene as the diluent and 5% tributyl phosphate (v/v) as the phase modifier, 94.81% V (V) and 95.78% Mo (VI) were obtained in a phase ratio (O/A) of 2 (7 min at 298.15 K in a single-stage contract) and aqueous pH of 1.8. After a two-stage of countercurrent extraction, over 99% V (V) and Mo (VI) were extracted while less than 1% Al and Mg were co-extracted. Upon a three-stage countercurrent stripping with 2.5 mol/L sulfuric acid at a phase ratio (O/A) of 2, the complete removal of vanadium (V) from the loaded organic phase could be achieved. In the selective stripping of molybdenum (VI), almost all of the molybdenum (VI) was stripped after two-stage countercurrent stripping using 2.5 mol/L ammonia. Both oxide components of vanadium and molybdenum can be achieved by further processing of stripped solutions, respectively. In addition, thermodynamic calculations showed that vanadium (V) extraction from the roasting-water leaching solution using P507 - N235 is an irreversible, exothermic reaction at 298.15 - 338.15 K.

Study on removal of molybdenum from ammonium tungstate solutions using solvent extraction with quaternary ammonium salt extractant

A new process for the removal of molybdenum from ammonium tungstate solutions using solvent extraction with quaternary ammonium salt extractant was proposed. The molybdenum can be selectively extracted over tungsten using a solvent extraction system consisting of 10% (v/v) N263 as extractant and 30% (v/v) isooctanol as modifier in sulfonated kerosene. The separation coefficient βMo/W reached 1 × 104.A continuous operation test was conducted using an industrial feed containing 2.2 g/L Mo and 258 g/L WO3. The concentration of Mo in raffinate decreased to <1 mg/L with mass ratio of Mo/WO3 <4.0 × 10−6 in four-stage counter current batch-continuous extraction at an A/O ratio of 3:1. After scrubbing, the loaded organic solution was first oxidized using 7% H2O2 followed by stripping using a mixed solution of 3 mol/L NH4HCO3 and 3 mol/L NH3·H2O in six counter current stages at an A/O ratio of 1:8. The stripping of molybdenum reached almost 100%, resulting in 62.1 g/L Mo and 0.96 g/L WO3 in the strip liquor with the WO3/Mo mass ratio of 0.015.This new process exhibited big advantages of wide adaptability, low tungsten loss, high value of molybdenum products, low cost and environmental friendliness.

Solvent Extraction of Molybdenum (VI) from Hydrochloric Acid Leach Solutions using P507. Part II: Stripping and Mechanism

ABSTRACTThermodynamic analysis of the Mo(VI)-H2A2-NH3-H2O system was conducted for the model establishment of molybdenum stripping from a loaded organic solution consisting of 30% (v/v) P507 in sulfonated kerosene. The results revealed that there were five ranges for the molybdenum stripping using ammonia, and the mole fraction of could be regarded as the saponification of the extractant. The molybdenum can be completely stripped at equilibrium pH higher than 5.0, and the consumption of ammonia for stripping 1 mol molybdenum can be expressed as: (mol), where P stands for the saturation of molybdenum in the loaded organic solution. The concentration of molybdenum in strip liquors reached as high as 228 g/L using a three-time reflux stripping with a loaded organic solution containing 35.9 g/L Mo and a stripping agent consisting of 1.2 mol/L NH3·H2O and 0.15 mol/L NH4NO3 at an A/O ratio of 1/2 and 30°C. The average stripping of molybdenum reached 96.4%, while the average molybdenum concentration in stripped organic solutions was only 1.30 g/L. The volume loss of strip liquor can be attributed to the formation of microemulsion during the stripping process.

Solvent extraction separation of molybdenum as thio-molybdate complex from alkaline tungsten leach liquor of spent HDS catalyst – A pilot study

Spent nickel-tungsten catalyst generated from hydrotreating petroleum industry always contains molybdenum about 0.1–2% as an impurity. Separation of Mo from spent Ni-W catalyst leach solutions is a critical step to produce high pure tungsten products like ammonium paratungstate (APT) and tungsten trioxide (WO3) for catalyst and tools applications. Though Mo and W have chemically similar properties but it is possible to exploit separation of Mo from W by modifying the aqueous phase species. In the present paper, alkaline leach liquor with a composition of 0.72g/L Mo and 18g/L W was taken. Selective separation of Mo as its thiocomplex from W was examined by Aliquat 336, a quaternary ammonium compound. Experimental parameters such as extraction pH, concentration of extractant and metal for extraction and selection of reagent and concentration for stripping were optimized to obtain maximum separation of Mo. Variation of extractant concentration indicated extracted Mo species as (R3CH3N)2MoS4. The McCabe-Thiele plots indicated that 2 and 3-counter-current stages are necessary at O:A ratio of 1:1 and 3:1 for quantitative extraction and stripping of molybdenum, respectively. A pilot run for 330h was operated with 3-stages of extraction, 1-stage of scrubbing, 3-stages of stripping and one stage of washing based on the equilibrium data to verify the performance of Mo separation from W from commercial point of view.

Extraction of molybdenum from acidic leach solution of Ni–Mo ore by solvent extraction using tertiary amine N235

ABSTRACTTertiary amine N235 diluted with sulphonated kerosene containing sec-octyl alcohol as a phase modifier was used to directly extract molybdenum from the acidic leach solution of Ni–Mo ore. The results indicated that the extraction of molybdenum can reach more than 88% using a solvent extraction system consisting of 10 vol.-% N235 and 10 vol.-% sec-octyl alcohol in sulphonated kerosene with an O/A ratio of 1:2 at room temperature for 20 min. The extracted molybdenum species of Mo7O21(OH)33–, MoO2(SO4)22– and MoO2(HSO4)42– in loaded organic phase were identified, and the predominant species was Mo7O21(OH)33–. Molybdenum in the loaded organic phase can be stripped with ammonia solution, and the stripping of molybdenum can reach 95.8% at an O/A ratio of 7:1, phase contact time of 10 min, and the ammonia concentration of 6 mol L−1.

Direct solvent extraction of molybdenum(VI) from sulfuric acid leach solutions using PC-88A

The extractant 2-ethylhexyl phosphonic acid mono-2-ethylhexyl ester (PC-88A) was used to directly extract molybdenum(VI) from high sulfuric acid leach solutions containing 3mol/L H+. The effects of extractant concentration, solution acidity and type of stripping reagent on the recovery of molybdenum(VI) were investigated. The saturated loading capacity of molybdenum(VI) with 40% PC-88A in sulfonated kerosene was 60g/L. More than 98.7% of the molybdenum(VI) was extracted in a four-stage counter current extraction using an organic system consisting of 40% PC-88A and 60% sulfonated kerosene and a feed containing 17.3g/L Mo(VI) and 157.3g/L H2SO4 with an A/O ratio of 3/1 at 20°C for 5min. The extracted molybdenum(VI) species of Mo2O5(HA2)2 in loaded organic solutions were identified by the combination of slope and saturation methods, and further proved by FTIR spectral analysis. The stripping of molybdenum(VI) was completed in a two-stage counter current stripping using 6mol/L of NH3 with an A/O ratio of 1/1.5 at 30°C for 5min. The concentration of molybdenum(VI) in the strip liquor reached as high as 146g/L.

Direct extraction of molybdenum from high acid leach solutions of Ni–Mo ore using an oxime extractant of HBL101

An oxime extractant of HBL101 was used to directly extract molybdenum (VI) from a strong acid leach solution of Ni–Mo ore. The organic system was optimized in terms of its organic composition and the conditions of extraction and stripping and further characterized in terms of the extraction and stripping kinetics and distribution isotherms and phase separation. More than 99.8% of the molybdenum was extracted by two-stage counter current extraction using an organic system of 10%HBL101+5%TBP+85% sulfonated kerosene and a feed containing 14.7g/L of Mo and 4mol/LH+ with an A/O ratio of 1:1.5 at 30°C for 5min. The loaded organic was stripped using ammonia solutions after scrubbing with de-ionized water. The stripping of molybdenum was completed by three-stage counter current stripping using 6mol/L of NH3·H2O with an A/O ratio of 1:4 at 30°C for 20min, resulting in the separation of molybdenum over nickel, iron, calcium, magnesium, aluminum, copper and zinc, and the enrichment and transformation of the molybdenum. The concentration of molybdenum in the strip liquor of pure (NH4)2MoO4 solutions reached 33.42g/L and increased to as high as 143.67g/L after reflux stripping. The extractant of HBL101 exhibited good performance and stability for reuse.

Separation and Recovery of Molybdenum from Acidic Solution using LIX 973 N

Leach liquors bearing 10.682 g/L Mo, 2.411 g/L Co, and 3.842 g/L Al obtained by the acid leaching of spent hydrodesulphurization catalysts were treated for the separation and recovery of Mo(VI) leaving Co(II) and Al(III) in the raffinate using solvent extraction by LIX 973 N. Equilibrium conditions for the extraction (loading) and stripping of molybdenum(VI) were determined. Extraction of molybdenum(VI) was increased from 13.9 to 96.7% with an increase in the extractant concentration from 2.5 to 30.0% (v/v) using 30% LIX 973 N in kerosene with feed pH 1.0 and a phase ratio of O: A = 1:1. The McCabe-Thiele plot for extraction of molybdenum(VI) with 30% LIX 973 N illustrated 2-stages at 2:3 (O: A) phase ratio and the loaded organic contained 16.021 g/L molybdenum(VI) indicating complete (99.9%) extraction. Stripping of molybdenum(VI) from the loaded organic was carried out with different (NH 4 ) 2 CO 3 concentration and a maximum of 98.45% stripping efficiency resulted at the unit phase ratio. Strip solution bearing molybdenum at about 48.049 g/L was achieved in 3-counter-current stages at O: A ratio of 3:1 with 1.5 M (NH 4 ) 2 CO 3 . High purity (99.9%) molybdenum trioxide prepared from the strip solution via crystallization was confirmed from the XRD study.

Study of molybdenum extraction by trioctylamine and tributylphosphate and stripping by ammonium solutions

The extraction of molybdenum from an aqueous solution by a tertiary amine extraction system was experimentally studied in this work. The organic phase is composed of trioctylamine (TOA) as the extractant, tributylphosphate (TBP) as the modifier, and kerosene as the diluent. The effects of various parameters including the concentrations of TOA and TBP, initial pH of aqueous phase, phase ratio of organic/aqueous, contact time of phases, type of diluent, and concentration of metal ions in the aqueous phase on the extraction of molybdenum were investigated. At the same time, stripping of molybdenum from the molybdenum-loaded organic phase using an ammonium hydroxide solution as stripping reagent was studied. The results showed that an extraction of 99.9% was obtained with the extraction system composed of 4vol.% TOA, 12vol.% TBP, and 84vol.% kerosene at a phase ratio of 1, initial pH=1, and contact time=600s. The difficulties in separating aqueous and organic phases were successfully obviated through addition of TBP to TOA extractant.

Solvent extraction of molybdenum from acidic leach solution of Ni–Mo ore

A P204 (D2EHPA) diluted with sulfonated kerosene was used for the selective extraction of molybdenum from an acidic Ni–Mo ore leach solution that was reduced using sodium thiosulfate. The results indicate that P204 (D2EHPA) is an effective extractant for the extraction of molybdenum. The extraction of Mo is more than 90 % at pH of 0.5, contact time of 10 min, and organic-to-aqueous phase (O/A) ratio of 1:1 with 10 vol% P204 (D2EHPA). Molybdenum in the loaded organic phase can be effectively stripped with ammonium acid carbonate solution, and the stripping of molybdenum with 60 g·L−1 ammonium acid carbonate solution is 94.67 % at O/A ratio of 2:1 and contact time of 10 min.

Recovery of molybdenum from the sea nodule leach liquor by solvent extraction using Alamine 304-I

Separation and recovery of molybdenum was investigated from the sea nodule leach liquor containing 0.505 kg/m 3 Mo(VI), 0.212 kg/m 3 Fe(III),12.08 kg/m 3 Cu(II), 2.012 kg/m 3 Co(II) and 15.16 kg/m 3 Ni(II). The recovery process was carried out in two key steps: (i) Solvent extraction of Mo(VI) from the leach liquor using Alamine 304-1 dissolved in kerosene and (ii) Preparation of MoO 3 from stripped solution by crystallization followed by thermal decomposition of ammonium polymolybdate crystals. In the solvent extraction study, the effects of several operational factors like contact time, pH, extractant concentration and different stripping reagents were examined to establish suitable conditions for effective extraction and stripping of molybdenum. The number of stages required for extraction and stripping were determined from a McCabe Thiele diagram and confirmed by a counter current simulation study. Enrichment of approximately 6.05 kg/m 3 Mo(VI) into the loaded organic phase was achieved with 10% (v/v) Alamine 304-1, at equilibrium pH 1.62, and A:O = 12:1. The McCabe Thiele diagrams at A:O = 1:16 with 5 M NH 4OH + 2.5 M (NH 4) 2CO 3 showed two theoretical stages needed for quantitative stripping of molybdenum. Ammonium polymolybdate was crystallized from the stripped solution (96.79 kg/m 3 Mo) and molybdenum trioxide was obtained by thermal decomposition at 400 °C with purity of 99.9%.

Studies on extraction behaviour of molybdenum (VI) from acidic radioactive waste using 2(ethylhexyl) phosphonic acids, mono 2(ethylhexyl) ester (PC-88A)/n-dodecane

This paper describes the studies on the extraction of molybdenum (VI) from aqueous nitric acid medium by (2-ethylhexyl) phosphonic acid, mono (2-ethylhexyl) ester (PC-88A). The extraction affecting parameters such as concentration of HNO3 in aqueous feed, effect of concentration of extractants, effect of diluents, and molybdenum concentration in the aqueous phase are investigated to optimize the extraction conditions for the quantitative separation of molybdenum from nitric acid medium. With increase of HNO3 concentration in aqueous phase, percentage extraction was found to be decreased in all the cases. Percentage extraction of molybdenum increases with increase in PC-88A concentration till the 0.15 M of PC88A, and after that it becomes constant. Kerosene and n-dodecane was found to be most suitable diluents. Among the various strippants used 0.2 M (w/v) solution of Na2CO3 and 0.2 M (w/v) solution (NH4)2CO3 are found to be the equally suitable for stripping of molybdenum from the loaded organic phase. The stripping of molybdenum from loaded organic layer by various reagents followed the order: (NH4)2CO3 >Na2CO3 >0.1 M sodium salt of EDTA >2 M NaOH >8 M HNO3. The optimized process conditions are employed to extract molybdenum (VI) from actual Davies–Gray waste as well as from diluted high level waste generated in the purex stream. More than 94% Mo(VI) was extracted from radioanalytical as well as from high level waste of purex process and quantitative recovery was achieved in both the cases when 0.2 M sodium carbonate was used as stripping agent.

A novel technology for molybdenum extraction from molybdenite concentrate

The technology of molybdenum extraction from molybdenite concentrate by using sodium chlorate has been investigated. The results show that leaching time, liquid-to-solid ratio, leaching temperature, agitation speed, sodium chlorate and hydrochloric acid concentration have significant effect; optimum process operating parameters were established as follows: time: 4 h; hydrochloric acid concentration: 20%; liquid-to-solid ratio: 10:1; temperature: 70 °C; agitation speed: 500 rpm; and the molar ratio of NaClO 3 to MoS 2: 3.21. Under these experimental conditions, the extraction of molybdenum is greater than 98%. The mixture of 30% triotylamine and 20% sec-Caprylic alcohol diluted kerosene oil is an effective extractant of molybdenum; the molybdenum extraction efficiencies in the examined conditions were about 99.6% under conditions of O: a ratio of 1:1, hydrochloric acid 60 g/L for 10 min at room temperature. Stripping of molybdenum to aqueous phase was efficient when 18% ammonia liquor were applied. The molybdenum stripping efficiencies in the examined conditions were about 99.5% under conditions of O: a ratio of 1:1 for 10 min at 40 °C.

Novel Method for Stripping of Molybdenum(VI) after Its Extraction with Cyanex 301

Hydrofluoric acid has been used as a novel stripping agent for molybdenum(VI) after its extraction with Cyanex 301. In the extraction step, the effects of parameters such as type and initial concentration of acid, type of diluent, extractant concentration, metal concentratio n and temperature have been studied. In the stripping step, the effects of various stripping agents on stripping efficiency have been investigated. Hydrofluoric acid has been chosen as an effective stripping agent, and the effects of concentration of hydrofluoric acid, stripping time, volume of hydrofluoric acid and the number of stages of stripping have been studied. Molybdenum(VI) has been effectively separated from a large number of elements in binary mixtures, with a very high tolerance limit. Finally, the optimized method has been extended for the analysis of Mo(VI) in spent molybdenum catalysts.

Extraction and selective stripping of molybdenum(VI) and vanadium(IV) from sulfuric acid solution containing aluminum(III), cobalt( II), nickel(II) and iron(III) by LIX 63 in Exxsol D80

5,8-diethyl-7-hydroxydodecane-6-oxime (LIX 63), a commercially available reagent, has been used in this work to investigate the extraction of molybdenum(VI) and vanadium(IV) from sulfuric acid solution in the presence of various other metals, such as aluminum(III), cobalt(H), nickel(II) and iron(III). Molybdenum(VI) and vanadium(IV) were extracted preferentially and separated completely from the coexisting metals involved at low pH (e.g., around 1.5) with LIX 63 dissolved in Exxsol D80. Vanadium(IV) in the loaded organic phase was selectively stripped by contacting with a 2 M sulfuric acid solution and isolated from molybdenum(VI). Molybdenum(VI) in the organic solvent, after the removal of vanadium(IV), was easily stripped by employing an aqueous ammonia solution as stripping agent and excellent phase separation performance (rapid phase separation, no formation of a second organic phase and no generation of an emulsion) in the stripping process was observed in all cases. A special emphasis, at least as an example of potential application, has been put on the extraction recovery of molybdenum(VI) and vanadium(IV) with LIX 63 extractant from the acidic sulfate liquor containing a sufficient quantity of aluminum(III), an appreciable amount of cobalt(II) and nickel(II), as well as a small amount of iron(III), resulting from the sulfuric acid leaching of spent hydrodesulfurization catalysts. The results obtained using the synthetic solution are in good agreement with those using the real leach liquor.

Ion Implantation in InSb Grown on GaAs

ABSTRACTBe, S, Si, and Ne implantations were performed at room temperature into InSb layers grown on undoped semi-insulating GaAs substrates. The implant damage in InSb is of ntype behavior. The implanted material was subjected to both isochronal and isothermal annealing schemes using a molybdenum strip heater. A maximum p-type activation of 90 % and si-type activation of 16 % was achieved for Be and S implants, respectively. Si implant has an amphoteric doping behavior.