Recycling Aluminum Oxide and Waste Disposal
Sunbelt Industries has been in the business of recycling aluminum oxide since 1978.
With our location in Oklahoma, the company routinely processes from 7 to 9 million pounds per year.
Aluminum oxide can be recycled because of its unique chemical and physical properties. The foremost property is that aluminum oxide is totally inert. This means that nothing reacts or interacts with fused aluminum oxide. It does not oxidize, it does not absorb, it does not change chemically or physically in any way in use or disuse. Except: the grains do fracture (become smaller) when exposed to great pressure.
At this point, the material is ready to be recycled.
It is important to note that Sunbelt Industries does not deal with any materials that are hazardous. Nor is material accepted that is not originally of the highest quality.
Before Sunbelt accepts material for recycling the generator must prove that the material is unregulated and non‐hazardous. We require a TCLP on the material before it is accepted for recycling and we require periodic updates to the TCLP.
Virtually all of the aluminum oxide is recycled and sold for blasting applications. Material that is too fine for such applications is sold to the refractory and polishing industry for the production of products such as grease bars, fire brick, and refractory shapes and fillers. There is virtually no waste from the aluminum oxide itself.
Periodically trash, floor sweep, gloves, etc. will be mixed with the aluminum oxide material to be recycled. These items are removed from the material and disposed of as ordinary industrial waste.
Why Aluminum Oxide Can Be Recycled
In a blasting operation, for example, the grain will fracture during use. This fracturing is not at a set rate. Some grains will fracture fairly quickly. Others may be used 20 or more times before they facture. The grains tend to fracture along planes of greatest weakness within the grain crystal.
When fracture does occur, each individual piece of the fracture becomes a new distinct crystal with the same dimensional and structural properties that the original, larger crystal exhibited. This is true regardless of the starting size of the crystal itself. Because the crystal broke at the points of greatest weakness, the resulting crystals tend to be stronger than the original.
When aluminum oxide is used in blasting, two things happen to the grit. First, over time it fractures into smaller grains. Second, the residue of the material being blasted becomes mixed with the aluminum oxide.
Aluminum oxide is discarded when the amount of breakdown has been sufficient to yield a work mix that has become too small to impart the intended surface finish or permit the desired cleaning rate.
At this point, the material is ready to be recycled.
How is Aluminum Oxide Recycled?
Recycling is accomplished by separating the aluminum oxide from the extraneous material that was picked up during the blasting and handling process. The material is sized to standard industry specifications (ANSI) and packaged in accord with the customer’s requirements.
The exact measures of recycling processes are proprietary to Sunbelt Industries. But the process is essentially composed of a series of operations and techniques that separate the aluminum oxide grains from all other materials that are mixed with the aluminum oxide as it is received from the generator.
How Does Recycled Aluminum Oxide Compare with New Material?
Sunbelt Industries believes that its recycled aluminum product is substantially the equal of new material. Because the initial use of the aluminum oxide exposed the crystals to pressure that caused breakdown at weak points, the resulting product is refined in use yielding a stronger crystal, one that is now capable of a longer work life.
The recycled crystal is blocky in nature. Some new materials may have a crystal structure that might be described as shard‐like. The shard‐like grains make a faster first cut than grains with a blocky structure, but the shard‐like grains tend to breakdown fairly rapidly. As it is used, the shard‐like grain itself becomes blocky as the more delicate exposed edges fracture.
Sunbelt grades its products to the exact same industry specifications that are used by manufacturers of new material. However, Sunbelt typically grades its material more tightly than new material, primarily because such grading eliminates dust.