| DEGREASING AND PAINT
STRIPPING USING SPONGE BLASTING dichlorothane, 1-butanol, butyric alcohol, CH3(CH2)2CH2OH; plumbum,
Pb; Cr; methylene dichloride
Revision: 7/96 C6H5OH; chloracetic acid, MCA, monochloroacetic acid Process Code: Navy and Marine Corps: ID-01-03; Air Force: ST01; Army: DPT Usage List: Navy: Low; Marine Corps: Low; Army: Low; Air Force: Low Substitute for: Sand Blasting and Chemical Paint Stripping CH2Cl2carboxyic acid Applicable EPCRA Targeted Constituents: Toluene (CAS: 108-88-3), Xylenes (CAS: 1330-20-7), Methyl Ethyl Ketone (CAS: 78-93-3), Acetone (67-64-1), n-Butyl Alcohol (CAS: 71-36-3), Lead (CAS: 7439-92-1), Chromium (CAS: 7440-47-3), Zinc Compounds, Methylene Chloride (CAS: 75-09-2), Phenols (CAS: 108-95-2), Chloroacetic Acids (CAS: 79-11-8) CH2ClCOOH Methyl benzene, phenylmethane, C6H5CH3;
dimethylbenzene, C6H4(CH3)2; ethyl methyl Sponge blasting systems are a class of abrasive blasting process using
grit-impregnated foam and non-abrasive blasting media using foam without
grit. The sponge blasting system incorporates various grades of
water-based urethane-foam cleaning media used to clean and prepare
surfaces. The non-abrasive media grades are used to clean delicate
substrates. The abrasive media grades are used to remove surface
contaminants, paints, protective coatings, and rust from a variety of
surfaces. In addition, the abrasive grades can be used to roughen concrete
and metallic surfaces, if desired. The abrasive media contains a variety
of grit, depending upon application, including aluminum oxide, steel,
plastic, and garnet. The classifier unit is used to remove large debris and powdery residues
from the foam media after each use. The used media is collected and placed
into an electrically-powered sifter. The vibrating sifter classifies the
used media with a stack of progressively finer screens. Coarse
contaminants, such as paint flakes, rust particles, etc., are collected on
the coarsest screens. The reusable foam media are collected on the
corresponding screen size. The dust and finer particles fall through the
sifter and are collected for disposal. After classifying, the reclaimed
foam media can be reused immediately in the feed unit. The abrasive media
can be recycled approximately six times and the non-abrasive media can be
recycled approximately 12 times. During degreasing applications, the foam media must be washed every
three to five cycles. The washing of the foam media takes place in the
wash unit, which is a portable centrifuge, closed-cycle device. The
contaminated wash water is collected, filtered, and reused within the wash
unit. This system removes paint, surface coatings, and surface contaminants
from a variety of surfaces. Waste streams produced from this system
includes coarse contaminants, such as paint flakes, rust particles; dust
and finer particles; and the concentrated residue from the bottom of the
wash unit. The effect that this technology has on pollution prevention is that the
stripping media can be recycled (10-15 events) and the quantity of
wastewater which is typically generated using conventional methods
(chemical stripping) is greatly reduced. Materials Compatibility: Sponge blasting systems are compatible in most situations where other
types of blasting media have been used. Safety and Health: As with any blasting operations, airborne dust is a major safety and
health concern. Proper precautions should be taken to ensure inhalation of
dust/particulate matter is avoided. Additional protective measures should
be taken when stripping lead chromate- or zinc chromate-based paints, as
these compounds may be hazardous. Inhalation of lead and zinc compounds
can irritate the respiratory tract, and some compounds are known to be
carcinogenic. Inhalation of solvent vapor can irritate the lungs and
mucous membranes. Prolonged exposure can affect respiration and the
central nervous system. Proper personal protective equipment should be
used. Consult your local industrial health specialist, your local health and
safety personnel, and the appropriate MSDS prior to implementing this
technology. Benefits:
Disadvantages:
Economic Analysis: The cost elements of a Sponge-Jet™ stripping system are compared to
chemical stripping. Assumptions:
Economic Analysis Summary Annual Savings for Sponge-Jet™: $67,710 Capital Cost for Diversion Equipment/Process: $47,750 Payback Period for Investment in Equipment/Process: < 1 Year Approving Authority: Navy: Unless locally controlled, no major claimant has endorsed this
technology for use on aircraft components without subsequent additional
treatment to ensure that the substrate is completely free of blast media.
This recommendation should be implemented only after engineering approval
has been granted by cognizant authority. Points of Contact: Scott Mauro Vendors: The following is a list of sponge blasting manufacturers. This is not
meant to be a complete list, as there may be other manufacturers of this
type of equipment. Sponge-Jet™ Source: Sponge-Jet™, May 1996 |