1. PRODUCTION OF BIO-GREASE FROM SCRAP ALUMINIUM
Session : 2009-10
Department of Applied Chemistry And Chemical Engineering.
Noakhali Science and Technology University.
2. What is a bio-grease?
Grease may be defined as a solid to semi-solid material
produced by the dispersion of a thickening agent in a liquid
Grease-lubricated bearings have greater frictional characteristics
due to their high viscosity. A grease is expected to reduce
friction and wear, provide corrosion protection, seal bearings
from water and contaminants, resist leakage, resist change in
structure or consistency during service, maintain mobility under
conditions of application, be compatible with seals, tolerate or
But one of the major concerns of using this grease is their
hazardous effect on environment. For this reason, the concepts
of bio-grease have come.
3. Bio-grease is a readily biodegradable, non-toxic, designed to
provide high film strength, withstand high operating
temperatures, maintain excellent stability and extended lubricant
Al-based bio-grease may be a good example of bio-grease. One
of the major advantages of Al-based bio-grease production is the
availability of major raw materials such as Aluminum scrap,
Stearic acid and Vegetable Oil ( Castor oil ) .Moreover all of the
raw materials are natural product.
The ancient Egyptians made grease from animal fats, resins and
lime to reduce axle friction as far back as 1400 B.C.
Good lubricating greases were not available until the development
of petroleum based oils in the late 1800’s.
Lithium, barium and aluminium salt base greases started to be used
in the 1920’s and 1930’s.
By the 1940’s and 1950’s the first complex base greases appeared.
5. Application suitable for grease
Machinery that runs from time to time or is in storage for an
extended period of time.
Machinery that is not easily reached for frequent lubrication
Machinery operating under extreme conditions such as high
temperatures and pressures, shock loads or slow speed under
6. Properties of grease
4. Dropping point.
6. High temperature effect.
7. Low temperature effect.
8.Corrosion and rust.
7. Physical properties
Properties Aluminum Sodium
110 163-177 135-143 177-204
100 121 110 135
Water resistance Good to Excellent Poor to fair Good Good to Excellent
Work stability Fair Fair Good to excellent Good to Excellent
Oxidation stability Excellent Poor to good Fair to excellent Fair to excellent
Good to excellent Good to excellent Poor to excellent Poor to excellent
Oil separation Good Fair to good Good Good to excellent
Appearance Smooth and Clear Smooth to fibrous
8. Function of grease
1.Reduce friction and wear in the machine element being lubricated
under various operating conditions.
2.Protect against rust and corrosion.
3.Prevent dirt, wear and other contaminants from entering the part
4.Maintain its structure and consistency during long periods of use.
5.Permit free motion of moving parts at low temperature.
6.Compatible with the seals and other material associated with the
parts being lubricated
7.Resist some degree of moisture contamination.
8.Resist change in structure or consistency during service
10. Application of grease
Automobile Wheel Bearings:
Manufacturing and Assembly Plants:
Farming and Construction:
11. DIFFERENCE BETWEEN LUBRICATING GREASE & LUBRICATING OIL
LUBRICATING GREASE LUBRICATING OIL
1. Lubricating grease act as a seal against
the entrance of dirt & dust.
Lubricating oil does not act as a seal
against foreign particles.
2. Less expensive. Cost is more than lubricating grease.
3. Retention time & stickiness is more
than lubricating oil.
Retention time & stickiness is less than
4. Saponification reaction is the key
factor of lubricating grease.
Saponification reaction does not take
5. Operating over wider temperature
Operating temperature range is less
than lubricating grease.
6. Solve the problem of lubrication
without corrosion in presence of water.
Cannot used in the presence of water.
12. GENERAL GREASE MAKING PROCESS:
There are two different methods–
1. Batch process.
2. Continuous process.
ADVANTAGE OF BATCH PROCESS OVER CONTINUOUS PROCESS:
1.Manufacturing operation in which flexibility required is a mixture of
2.Manufacturing a different product that is in higher demand.
3. Equipment can be reuse.
4. Process variables can be subjected to adjustments.
5. Multi-product operation can be done.
6. Grease has a demand that changes over time or has seasonal variability
and this type of variability is well suited to batch manufacturing.
7. Cost required is less in case of batch process.
14. Factors affecting the quality of grease
Rate of saponification reaction
Acidity / Alkalinity
Rate / Sequence of addition of additives and oil
Temperature of grease formation
Temperature of additive addition
Temperature and duration of de-aeration, filtrations and
15. Factors affecting the growth of grease industries:
Second World War: The Second World War, particularly for
aircraft lubricating grease demand.
Industrial Growth: Basic industries to which improved
lubricating greases have made a valuable contribution are in
manufacture industries and maintaining maximum capacity of the
various operating units.
Growth in Automotive Sector: Valuable and important
contribution to the operation of equipment used in vehicles,
which are used for transportation of goods and people.
16. Worldwide grease production:
According to the NLGI Grease Survey, North America reported
grease production of 544 million pounds, which is approximately
29 percent of the worldwide grease production. All countries
participating in the survey reported a total production of 1.9 billion
pounds of grease
Figure: Worldwide grease production Chart.
20. Raw materials For General Grease making -
+ + =
A wide range of lubricant base fluids is used in grease
technology. However, the largest segment consists of a
variety of products derived from the refining of crude oil and
downstream petroleum raw materials. There are three basic
groups of mineral oils: aromatic, naphthenic and paraffinic.
70 – 75% Base oil
0 – 2% Additives25 – 30 % Thickener
21. LUBRICATING OIL:
The high percentage of oil by weight (70 – 75) % in a
grease necessitates that it be of high quality and proper
viscosity for the intended application.
A light viscosity oil is normally used for low temperature,
low load and high speed applications.
Conversely heavy viscosity oil is generally used for high
temperature, high load and slow speed applications
22. Vegetable oil (Castor oil):
English name : Castor oil
Malaysia : Jarak belanda.
Bangladeshi : Varenda.
It is obtained by pressing the seeds of the castor plant, Sometimes called castor
Figure : Castor oil (Varenda oil) tree and seeds.
A 66-year-old brand that's become a generic name for hydrogenated vegetable oil
popular in South Asia. Hydrogenation results in the conversion of liquid
vegetable oils to solid or semi-solid fats.
Molecular Formula : C30H45N9O5
Formula Weight : 611.74
Storage temperature : Bellow 20°C
Form : Solid
Color : white
24. DENSITY OF VEGETABLE OIL:
Density is defined as mass per unit volume. The mass density or density of a
material is its mass per unit volume. The symbol most often used for density is
Density, ρ = m / v ………………………………… (1)
Where, ρ is the density, m is the mass, and V is the volume. Different materials
usually have different densities.
Density of water at 1 atm and 150C = 999.1026 kg/m3.
Calculation (Raw vegetable oil):
Density of oil = 44.41g / 50g * 1 g/cm3 Where, mass of oil = 44.41g
= 0.89 g/cm3 mass of water = 50g
Density of water at 1 atm and 150C = 1 g/cm3.
25. Density of heated vegetable oil calculation:
Density = 45.09g / 50g * 1 g/cm3 Where, mass of oil = 45.09g
= 0.90 g/cm3 mass of water = 50g
26. MEASUREMENT OF OIL VISCOSITY BY FALLING BALL VISCOMETER
Objectives: To measure the viscosity of Vegetable Oil.
Apparatus: (1) Falling ball viscometer (2) Viscometer balls (3) Pycnometer (4)
Retort stand (5) Weighing balance (6) Volumetric flask (7) Stopwatch (8)
Glassware (9) Cleaning accessories and (10) Distilled water.
Figure : Falling ball viscometer.
Viscosity of Vegetable Oil before heating:
Viscosity h = K (ρ1 – ρ 2 ) * t
Where, K = Ball constant, ball const K is determined for a standard liquid of
viscosity = 0.07. Average falling time t = 270 sec
ρ1 = Density with ball constant = 8.1 (g/cm3)
ρ2 = Density of the sample oil = 0.89 g/cm3
Viscosity = 0.07 (8.1 – 0.89) * 270 mPa.s
= 136.27 mPa.s
Viscosity of Vegetable Oil after heating:
Viscosity h = K (ρ1 – ρ 2 ) * t
Where K = Ball constant, ball const K is determined for a standard liquid of
viscosity = 0.07. Average falling time t = 242 sec.
ρ1 = Density with ball constant = 8.1 (g/cm3)
ρ2 = Density of the sample oil = 0.9 g/cm3
Viscosity = 0.07 (8.1 – 0.90) * 242 mPa.s
= 121.97 mPa.s
28. DETERMINATION OF ACID VALUE (Castor oil)
The acid value is the number of mg of potassium hydroxide required to
neutralize the free fatty acids in the sample. Acidity (as defined in USP) is
expressed as the number of milliliters of 0.1N alkali required to neutralize the
free acids in 10 grams of the substance.
Accurately weigh about 10 g of the sample oil into a 250-ml flask, and add 50
ml of a mixture of equal volumes of ethanol and toluene. Shake the mixture
Then add 1 ml of phenolphthalein/ethanol, heat, if necessary.
Titrate with potassium hydroxide (0.18N), constantly shaking the contents of the
flask until a pink colour, which persists for 15 seconds, is obtained. Note the
number of ml required of potassium hydroxide (KOH).
Calculate the acid value from the following formula, which has been neutralized
with potassium hydroxide 0.18N
Acid value (before heating) = 0.18 x 56.1 x 10.6 / 10(weight of oil) = 10.7
Acid value (after heating) = 0.18 x 56.1 x 10.10 / 10(weight of oil) = 10.2
The thickener is a material that in combination with the selected lubricant, will
produce the solid to semi fluid structure. The primary type of thickener used in
current grease is metallic soap. These soaps include lithium, aluminum, clay,
Polyurea, sodium and calcium.
Soaps include calcium stearate, sodium stearate, lithium stearate, as well as
mixtures of these components.
Mainly two of the non-soap thickened greases are significant- clay and urea.
Clay: A form of bentonite (clay-like) materials consisting of hydrous aluminum
Urea: Also known as polyureas, they are made with ash less organic thickeners.
These greases have a natural resistance to oxidation
Additives can play several roles in lubricating grease. These primarily include
enhancing the existing desirable properties, suppressing the existing undesirable
properties and imparting new properties.
FUNCTIONS TYPE OF ADDITIVES
Antioxidant Phenols, Amines, Phosphorous Compound, Sulfur Compound.
Extreme Pressure &
Amine Phosphate , Tri phenyl-thiophosphate.
Rust Inhibitor Barium & Calcium Sulphonates.
Corrosion Inhibitor Alkyl Benzene Sulphonates.
Anti-wear Antimony, Di Alkyl Di-thio Phosphate
Water Repelling Agent Fatty Oils
Tackiness Agent Polymers (Methacrilate)
Friction Modifiers MoS2, Graphite.
31. Aluminium scrap Pretreatment:
Aluminum scrap comes from a variety of sources. "New" scrap is generated by pre-
consumer sources, such as drilling and machining of aluminum castings, scrap
from aluminum fabrication and manufacturing operations.
"Old" aluminum scrap is material that has been used by the consumer and
discarded. Examples: aluminum foil, automobile and airplane parts, aluminum
siding and beverage cans.
Mechanical cleaning includes the physical separation of aluminum from other
scrap, with hammer mills, ring rushers and other machines.
1.At first Scrap-Aluminium have to cut into 1cm sizes.
2.Cleaned with cleansing agent and again cut as much smaller as possible.
3.Kept the Al-scrap into 5M H2SO4(aq) for H2(g) gas and dust removal about two
4.At last these scrap-Al reacts with H2SO4(aq).
35. So finally the complete reaction for the preparation of Al2(SO4)3(aq) is as follows-
15gm scrap-Aluminum(555.56 m.mole) + 99% pure 85ml H2SO4 (867.347m.mole)
3 hours heat Hand stirring
Chart : The above chart shows the Yield% against fixed volume of 15 gm scrap -
Aluminum with different wt.of H2SO4.
80 83 85 88 90
Different wt.of H2SO4
36. Properties of this Al2(SO4)3
1. White to off white lump.
2. Soluble in water, pH – 2.7 (5% solution).
3. Hard, durable, corrosion resistance.
4. Dissolve in alkaline water precipitate of Al2OH.
5. Aluminums content in Al2(SO4)3 = 16% .
37. STEP - 2: Preparation of Na-Stearate:
Stearic acid is the saturated fatty acid with an 18 carbon chain is a waxy solid and
its chemical formula is CH3(CH2)16C00H. Its name comes from the Greek
word "stear", which means tallow.
Stearic Acid + NaOH = Na-Stearate.
C17H35COOH + NaOH = C17H35COONa + H2O.
Stearic acid saponification conditions are very important for the process of
obtaining mono, di and tri-stearate aluminum salts. For this process is also
important the amount of applied alkali, i.e. molar ratio of the acid and alkali. In
the saponification reaction -
CH3 (CH2)16COOH + n NaOH = CH3 (CH2)16COONa + H2O
Here, n influences the equilibrium. When n value is higher, the reaction
equilibrium is shifted to the right .In this saponification reaction for obtaining
the highest yield of Na-Stearate, the “n” value for NaOH = 3 – 3.5
38. Experimental procedure
1. 7 24.65 2.5 62.5 70-80 Simult
2. 7 24.65 3 75 70-80
3. 7 24.65 3.5 87.5 70-80
39. STEP- 3: Na-Stearate + Aluminium Sulfate = Al- Stearate.
Procedure of aluminum stearate precipitation:
1. 10 32.68 10
2. 10 32.68 11
3. 10 32.68 12 35.07 Simul
Chemical Name : Aluminum Di-Stearate
Chemical formula : C36H71AlO5
Moisture : 1% maximum
Melting Point : 153° C.
Appearance and odor : White powder, slight fatty acid odor.
Ash content : Ash Content, % = (33.73 – 33.39) * 100 / 3.27 =
44. No. Yield % Moisture% Melting
F 92 0.02 83 93 4.95
G 96 0.01 92 107 5.59
H 94 0.01 95.5 112 6.34
I 92 0.02 87 102 4.91
J 90 0.16 81 90 4.23
45. METHOD OF DETERMINATION OF MOISTURE CONTENT:
Scope: This method is used to determine the percentage of water in grease
Drying equipment – An oven, hot plate suitable for drying moisture samples
at a uniform temperature not exceeding 239º F (115º C).
The moisture content of the sample is calculated using the following equation:
%W moisture = A− B / A * 100
%W = Percentage of moisture in the sample,
A = Weight of wet sample (grams), and
B = Weight of dry sample (grams).
46. DETERMINATION OF MELTING POINT:
Melting point: The temperature at which a solid melts is known as the melting
point (MP) of that substance. The melting point is a physical property of a solid
and can be used to help identify a substance. In practice, a solid usually melts
over a range of temperatures rather than at one specific temperature.
Figure : A Fisher-Johns melting point apparatus.
47. Melting point of different greases
A B C D E F G H I J
89 74 64.8 64.5 62.2 83 92 95.5 87 81
48. DROPPING POINT DETERMINATION, n:
A numerical value assigned to a grease composition representing the temperature
at which the first drop of material falls from the test cup. In general, the
dropping point is the temperature at which the grease passes from a semisolid to
a liquid state under the conditions of test.
Figure : A Dropping point apparatus
49. Dropping point of different greases
A B C D E F G H I J
96 81 72 70 68 93 107 112 102 90
50. DETERMINATION OF ASH CONTENT
Weigh a clean, dry crucible.
Take accurately weighted sample into the crucible.
Ignite the crucible about 4 hours and keep the sample into the muffle furnace
until all combustible matter has been removed for 3 hours about 14000C and
only ash appears to remain.
Allow to cool slightly then place it in a desiccator until cold.
Reweigh the crucible and contents.
Ash Content, % = (C X 100) / B
Where , C = ash, gm
B = oven-dried test specimen, gm.
Sample – A: Ash Content, % = (31.13 – 30.91) * 100 / 3.64 = 6.04
52. Result and discussion:
Experimental procedure - A (Step -4)
For a constant volume of Vegetable Oil (from Jatropha gossypifolia) 66.67%,the
parameters of the grease such as Yield%, melting point, moisture content, Dropping
point, ash content will vary according to the percentage of thickener(Aluminium
From the above chart we see that the highest melting point and dropping point are
found where the amount of Aluminium stearate is 35% with constant volume of oil
Where the percentage of thickener is used bellow 35% such 30%, 25%, 20%.10%,
the properties of the final grease also changed with poor grease parameters.
So we can say from the above discussion that for obtaining better quality grease and
maintaining desired parameters of grease the percentage of Aluminium stearate
(thickener) used must be within 30 – 35 % and the percentage of vegetable oil 66.67
– 70 %.
Thickener 35 – 30 % + Total oil 66.67% = Final grease.
53. 96 94 94 95 93
64.8 64.5 62.2
72 70 68
35 30 25 20 10
Yield % Melting point 0C Dropping point 0C
Chart: The above chart shows Yield%, Melting point and Dropping point of grease with
fixed percentage of vegetable oil against different percentage of aluminum stearate.
56. Experimental procedure - B (Step – 4)
From the above reaction number - H and chart, we see that
when the amount of thickener is 30% and dalda 40%, the final
product grease parameters such as Yield%, melting point,
moisture content, Dropping point, ash content is in maximum
and into the highest desired range.
In the above process no. G, F we see that the final product
grease properties decreases according to the percentage of dalda
33.33% and 25% within total oil 100% with respect to
57. Again, in the reaction number I & J, we see that the final product
grease properties also decreases compare to the reaction no. H
according to the percentage of dalda 50% and 57.14% within
total oil 100% with respect to vegetable oil (Jatropha
So we can say that the percentage of dalda will keep constant
within 33.33% - 40% for obtaining better quality of grease into
the total percentage of vegetable oil 100%.
30% thickener + Total oil (33.33 – 40 % Dalda + 60 – 67 %
Vegetable oil) = Final grease.
58. Total % of Dalda
Total % of vegetable oil
Chart: The above chart shows Yield%, Melting point and Dropping point of grease
with fixed Aluminium stearate and Vegetable oil against different percentage of
92 96 94 92 90
25 33.33 40 50 57.14
Yield % Melting point 0C Doppping point 0C
59. Chart: The above chart shows Moisture% of grease with fixed Aluminium
stearate and Vegetable oil against different percentage of Dalda.
25 33.33 40 50 57.14
60. Chart : The above chart shows Ash% of grease with fixed Aluminium
stearate and Vegetable oil against different percentage of Dalda.
25 33.33 40 50 57.17
It is evidenced from the data obtained from this thesis work that the aim of
producing a bio-grease and some characteristics was met and it can be concluded
that the vegetable oil (from Jatropha gossypifolia) and Dalda used is a good
renewable source for biodegradable grease production.
Many grease samples were successfully produced with different compositions of
the base oil, thickener and also under different conditions while the grease
produced after being subjected to the necessary tests was far better than
commercial grease used as controls.
The fact that the dropping point of final grease depends largely on the
composition and consistency (30% thickener + Total oil (33.33 – 40 % Dalda +
60 – 67 % Vegetable oil).
62. Finally, the limitations identified were due to lack of efficient
magnetic stirrer and the finance to carry out some further tests
such of moisture, ash content and so on but however these are
recommended for further research works.
These greases, however, have some unique qualities which are
quite desirable and have contributed to the rapid increase in
acceptance for both industrial and automotive applications. Well-
formulated aluminum grease will have excellent water resistance.
By making and the use of Bio-grease, local economy’s can not
only save via landfill avoidance, drain maintenance and health
costs, they can share in profits derived from the production sell of