Transcript Adsorbents and Zeolites - Supplemental Teaching Resources

Adsorbents and Zeolites
©2010 Dr. B C Paul
Notice – Information and figures in these slides were collected from a wide
range of sources including but not limited to publications from SME and the
USGS and pictures from internet sources dealing with Minerals Data.
Zeolites
• Actually a family of related mineral
structures with very high internal surface
area
– It can act as a molecular sieve by grabbing
some small molecules while letting larger
ones pass
– High surface area provides a big surface area
to stage reactions – makes a great catalyst.
Zeolites Formed
• Formed from weathering, dissolution and
reprecipitation in fine grained high silica
igneous rocks or sedimentary deposits
derived from them
– Generally looking for tuffs or glassy volcanic
flows.
• Most commercial deposits will have about
50 to 80% Zeolite
Clinoptilolite
(Na,K,Ca)2-3Al3(Al,Si)2Si13O36•12(H2O)
Color Colorless, White, Red.
Hardness 3.5-4
SG 2.15
Non Magnetic
Fluorescent UVC Light Green
Streak White
Most common commercial zeolite
Considered Group 7 a titanium oxide structure
Mordenite
(Ca,Na2,K2)Al2Si10O24•7(H2O)
Color Colorless, White, Yellowish,
Pinkish
Hardness 5
SG 2.12
Non Magnetic
Non Fluorescent
Streak White
More rare but commercial
Has a type 6 Titanium oxide structure
Chabazite
(Ca0.5,Na,K)4[Al4Si8O24]•12H2O
Color Colorless, Green, Yellow, White, Pink.
Hardness 4
SG 2.09
Non Fluorescent
Non Magnetic
Streak White
Has a group 4 (D6R structure) – Commercially Important
Erionite
(Ca,K2,Na2)2[Al4Si14O36]•15(H2O)
Color White, Green, Gray, Orange
Hardness 3.5-4
SG 2.11
Non Fluorescent
Non Magnetic
Streak White
Has a group 2 (S6R) structure
Phillipsite
(Na,K,Ca)1-2(Si,Al)8O16•6(H2O)
Color White, Reddish white, Light yellow,
Pink
Hardness 4 to 5
SG 2.2
Non-Fluorescent Non Magnetic
Structure Group 1 (S4R)
Ferrierite
(Na,K)2Mg(Si,Al)18O36•9(H2O)
Color Colorless, White, Pink, Orange,
Red
Hardness 3-3.5
SG 2.14
Non Magnetic
Non Fluorescent
Streak White
A group 6 (T8O16) structure like Mordenite
Useful but currently found in only a few locations
Other Common
(but not heavily commercialized Zeolites)
Heulandite
Laumonite
Offretite – an associate of
Phillipsite
Zeolite Uses
• About 80% of Zeolite Use
–
–
–
–
Animal Feed
Pet Liter
Water Purification
Odor Control
• Other Uses
–
–
–
–
–
Fungacide or pesticide carrier
Oil absorbent / Desiccant
Catalyst
Horticulture
Aquaculture (keeps water clean in the presence of
overpopulation)
Processing of Zeolites
• Selective mining tends to get specific mixes of zeolite
• Main process thrust is in sizing
– Crushing and screening can produce coarser sizes with lots of
fines at low value
• About 1.5 to 3 cents per pound
• Suitable for soil conditioner and pet liter
– Fine Grinding for -60 mesh to 325 mesh products
• About 5 cents per pound
• Best grades for things like fish tanks 25 cents to $2/lb
– Can acid wash to put faster reacting Na on active sites
• Can get into the $3.5/lb range
• Lots of Zeolite Operations run production to as captive to
the needs of a specific customer.
Diatomite
• The fossil amorphous silica shells of little
Diamtoms
• Very light and porous structure
– It is inert
– Can be used to filter things
– Can be ground fine and used as a mineral
filler
– It is a soft abrasive that tends to give a mild
polish rather than wear things down.
Diatomite
Uses of Diatomite
Uses of Diatomite
1
2
8
9
Filters
Cement additives
48
Absorbants
Fillers
Insulation
Other
33
Mining of Diatomite
• Preferred method is surface quarrying
– Individual benches allow differing products to
be mined and mixed
• It is soft so it can be dug directly without
blasting
Processing
Break it up into individual
Diatoms
Make the contaminants
Stand out because they
Break-up differently
It is next blown by heated
Air into milling fans for
Drying a grinding
Sorted by Size With Air Separators
and Cyclones with Coarse Recycle
Coarser grades go for Filters
Finer Grades go for Mineral Fillers
What is Diatomite Worth?
Price of Diatomite
Filter Grade Price
Per pound is about
10 to 15 cents
0.25
$2009 / Lb
0.2
0.15
Price of Diatomite
0.1
0.05
2008
1996
1984
1972
1960
1948
1936
1924
1912
1900
0
A rough cement lightner is only about 0.4 cents per pound
But cosmetic grade can go for $1.60 per pound
What Are Reserves and Production
Production and Reserves of Diatomite
Spain
Peru
2500000
Mexico
Japan
2000000
Metric Tonnes
Other
Italy
Iceland
1500000
Germany
France
1000000
Czech Republic
Costa Rica
500000
Old USSR
China
0
Production
Reserves/500
Chile
United States