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REFLECTION FOR MIXING :<3: (General Process Flow (Droplet air-contact,…
REFLECTION FOR MIXING :<3:
The importances of mixing in ceramics process
Increase the homogeneity of raw materials chemical & physical conditions
Increase and optimise the quality of final end product
Imperative in minimizing the investment of operating cost when provided with high yields
Enhancing the profitability
Mixing mechanism
Basically, it is done in briefly 3 stages or steps.
Mixing of X & Y materials > Convection > Shear > Diffusion
Convection
Transfer the components from a region to another
Shear
Increase components' interface via its shape
Diffusion
Exchange between the molecules particles in the materials neighbourhood
The Types of Mixers
Fluidization Blender (Plow Mixer & Paddle Mixer)
Tumble Blender (Bin Blender,V- Blender,Octagonal Blender)
Convective Blender (Ribbon Blender,Paddle Blender,Vertical Screw Blender)
Advantages & Disadvantages of Mixing Methods
Wet
(Adv):
Water level is controlled precisely
Less labor requirement
Low cost
Easy spraying operation
(Disadv):
Weak bond strength & tensile strength
Wastage material
High controlled of transportation is needed
Less air consumption
1.
Dry
(Adv):
Increase bonding ability & binding strength
Less waste created
Less investment
Water content is controlled at nozzle
(Disadv):
Higher cost
Water content must be controlled via nozzle
High dust emission
Dry & Wet
(Adv):
Very quality product
Less fatigue cracking
Less thermal & reflective cracking
(Disadv):
Higher cost
Longer duration/period
More space needed
Many equipments are needed
The Differences between Wet,Dry & Dry and Wet Mixing Methods
(For Wet Mixing)
Slurry
Have slip casting
High quality product is produced
Large energy consumption
(For Dry Mixing)
Mixture
No slip casting
Low quality product is produced
Small energy consumption
(For Dry & Wet Mixing)
Mixture + Slurry
Have reverse process
Higher quality product
Larger energy consumption
S.G Equation
(S.G = ( {solid weight in colloid} / {volume} )
[Importances]
Able to determine the production of slip casting
{water content is as low as possible}
Able to determine on how much powder mixture in slurry
Applied for wet mixing process
[Example]
A= 2500g of slip weight in 200ml
B= 500g of slip weight in 200ml
S.G = ( 2500-500 ) / (200)
= 10 g/ml
Brogniart Equation
W = (P-A){(S)/(S-1)}
[Importances]
Able to estimate the amount of dry material in a given volume slop
Able to calculate the actual density of dry glaze & local water
[Example]
P= 2.5kg, A=2kg, S=25 (based on theory)
W= (2500-2000){25/(2.5-1)}
= 8333.33 g
Spray Dryer
{Importances}
a) Desired Particle Product
Narrow particle distribution
Soluble in water
b) Cost Effective
Recycling heat exhaust gas
High yield that made up of different raw materials
c) Simple Process
Single and continuous
Final drying step is not necessary/not required
Factors / Parameters
Particle Size
Decrease
Decrease
Increase
-
Increase
-
Final Product Moisture
-
Decrease
-
Increase
Decrease
Decrease
Factors affecting shape/size of granule
Atomic size(disc rotation velocity)
Rate of hot air
Atomic size (feed pressure)
Rate of feed
Feed concentration
Hot air temperature
{
Types of spray dryers
}
Co current Disc Atomizer
Mixed Flow with Nozzle Atomizer
General Process Flow
Droplet air-contact
Drying
Atomization
Separation of powder from moist gas
Concentration
Produced by:
Muhammad Iman Rif'at bin Muhammad Sabri
Matric No. (144768)
