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INTRODUCTIONWhat Sand Reclamation ?

Sand reclamation, the process of cleaning previouslyused sand so it can be reused.

Why sand reclamation ?

Due to environmental regulations, the disposal ofwaste foundry sand has become one of the mostpressing problems for the foundry.

In recent years because of the high disposal costsencountered and difficulty in finding disposal sites.

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Definition for Sand Reclamation

Sand reclamation is the physical, chemical or

thermal treatment of foundry sands so that

they can be safely re-used in place of new

sand in molding and core making mixes.

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Function of Sand Reclamation

Reduce all lumps to sand grain size.

The sand grain size distribution of the reclaimed sand

should be the same as that of the new sand as

purchased.

Remove all tramp materials such as metal particles ,

slag, refractory particles, etc...

Remove fines to a acceptable level.

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Types of sand Reclamation

Mechanical Reclamation

Thermal Reclamation

Dry Reclamation

Wet Reclamation

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Mechanical Reclamation

Mechanical sand reclamation systems remove

accumulated coatings around the sand grains.

As well as dust and other impurities that

would otherwise make the sand unusable.

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Steps involved mechanical reclamation

Mold + castings

Shake out gird

Secondary sieve

Compressed air is passed

Sieve for final crush it as fine sand

Automatic discharge of

castings and mud

Removal of

impurities

Sand collection

Reclamation of sand for

next lot

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Videos for Mechanical Sand

Reclamation

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you can search in youtube

Thermal Reclamation block diagram

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Thermal Reclamation

Most thermal reclamation systems are

preceded by mechanical systems.

That preparation the sand for thermal

treatment by removing metallic's and part of

the sand coatings.

Thermal reclamation system uses a unique

fluidized, gas-fired bed design to combust and

remove remaining residual sand coatings.

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Thermal Reclamation by process

Thermal Reclamation is the process in which

the sand is heated to a temperature of about

800°C.

The sand grains obtained from the lump

breaker is generally pre-heated .

And fed into the combustor where it is

fluidized by precisely controlled air flow at

desired pressure.

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Lump Reducer – It Reduces the de-moulded sand

lump into sand grains in a vibrating unit fitted with

unbalance motor.

Pneumatic Sand Transporter - to deliver the de-

moulded and reduced sand grains to the return sand

storage.

Screw Feeder - It feeds this sand in to sand preheating

unit.

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Sand Preheating Unit - fitted at the inlet of

the fluidized bed combustor to preheat the

incoming return sand by using waste heat in

the flue coming out from the combustor.

Air Pre heater - for further extracting waste

heat from flue.

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Fluidized Bed Combustor - where the

preheated sand is fed from the sand pre-heater

by a screw feeder and fluidized by preheated

air.

Preheated sand is further heated to about

800°C by heat provided from the Wesman

(company name) combustion system.

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Skip Hoist - for transporting hot reclaimed

sand into hot sand silo at the inlet of the cooler

in a particular model.

Fluidized Bed Cooler - where the hot

reclaimed sand is cooled to usable temperature

by means of fluidizing air as well as cooling

coil.

Dust Extraction System - having suction

points at various stages of reclamation for

removing dust as well as for classification of

sand.

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Dry Reclamation pictorial view

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Dry Reclamation

Dry reclamation processes first crush the lumps to

grain size.

Mechanical abrasion then removes part of the

binder from around the sand grains.

Released fines are separated and removes by dry

classification.

The impact of the sand scrubs off the clay coating

from the surface of the sand grain, and the

resulting fines are removed to a dust collector.

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Wet reclamation pictorial view

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Wet Reclamation

Wet reclamation technique is wet scrubbing, in

which suspended sand grains are subjected to

vigorous motion and mutual rubbing by water

currents, jets and agitation.

The main use of wet reclamation has been for

sodium silicate bonded sands, where the whole

of the binder residues can be effectively

removed.

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Wet reclamation can also be integrated with

hydraulic cleaning and decoring of castings

The same pressures will continue as a

powerful factor in the design.

This would clearly shift the balance from the

situation in which landfill dumping is the sole

alternative to reclamation.

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Major drawback on wet reclamation

In addition, capital cost of the equipment is

high .

A large amount of floor space is required.

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