型号:Minizone | 品牌:Design Scientific | 加工定制:否 |
Invented in the early 1950’s for the purification of semiconductors,
ZONE REFINING is the method of choice for ultra-purification of
organic chemicals. This technique:
• Requires no solvent or column
• Sample is 100% recovered
• Operates automatically
• Sample sizes from 250 mg to 4 grams
are easily purified
• Requires only minutes to set up.
Chemicals that melt without decomposition and are
at least partially crystalline are candidates for zone refining.
Applications include:
• Preparation of standards
• Isolation of Impurities
• Purification of laser dyes, scintillation materials,
organic semiconductors
• Study of ultra-pure chemicals
MiniZone Refiner Specifications
Number of Zones Four Hot; Four Cold
Sample Tubing Size Large: 165 mm long X 6.1 mm OD, Medium: 165 mm long X 4.4 mm OD
Heating 125 watts. Platinum RTD temperature sensor with proportional control
Temperature set to nearest 1 ºC, Maximum Temperature: 250 ºC
Tube Transport Stepper Motor Control, Continuously Variable from 1 to 90 cm/hour.
Electrical 110-120 Volts or 220-240 volts @ 50-60 Hz, 400 Watts.
Voltage set at time of manufacture
Physical 36.5 cm (14.375”) long X 20.3 cm (8”) high X 20.3 cm (8”) wide 5.45 Kg (12 lbs)
In Zone Refining, a short molten zone travels slowly
through an elongated sample of a crystalline material.
A molten zone traversing a solid sample has two
liquid-solid
interfaces;
a melting
interface and
a freezing
interface.
At the melting
interface the
composition
sample of a crystalline material. A molten zone traversing
a solid sample has two liquid-solid interfaces;
a melting interface and a freezing interface. At the
melting interface the composition does not change
but at the freezing interface, the impurities favor the
liquid phase because the crystal structure tends to
exclude molecules that do not readily fit into the
crystal lattice. Passing the molten zone(s) through the
sample many times concentrates the impurities at one
end leaving the opposite end highly purified.
The photo shows a
sample during the
refinement process
in the MiniZone refiner.
The sample is
contained in one (or
two) disposable, thinwalled
Teflon® sample
tubes. These tubes are
filled with the sample
and clamped on
each end in the tube
transport mechanism.
(The metal blocks at
the top and bottom
of the photo.) The
transport mechanism
slowly moves the tubes
downward, passing
them through the
four heating and four
cooling zones of the
temperature regulated
metal blocks. After the
tubes move downward
the distance of one hot
zone and one cold zone (two centimeters), the transport
mechanism is reversed and the tubes are quickly
moved upward to the original position. The net result
of this motion is that the molten and crystalline zones
migrate slowly and continuously upward with respect
to the tubing.
With a typical zone rate of 2 cm/hr and with four active
zones, each portion of the sample is subjected
to one purifying phase transitions per hour. Usually
within 18 hours of automatic operation (18 recrystallizations),
the sample is purified. After the sample tube
is cooled, it is removed from the MiniZone. The refined
sample is easily recovered by cutting the tube into
sections. The major portion of the impurities are concentrated
at one end of the tube.
For more information on zone refining, please visit
our web site atwww.resolutionsys.com.