Reclamation Rule Enforcement On the Rise
As the regulation debate continues, emissions standards and Subpart UUU affect metalcasters processing sand onsite. BY DENISE KAPEL, SENIOR EDITOR
equipment that thermally pro- cesses industrial sand and meets the regulatory definition of a dryer or calciner. Within the metalcast- ing industry, EPA has determined thermal sand reclamation units meet the definition of a calciner.
T
he U.S. Environ- mental Protection Agency (EPA) is enforcing air qual- ity regulations for
Regulatory Background
In 2008, EPA proposed a change to the language of the NSPS to exempt metalcasting facilities. But, that step was never completed and at least one regional agency began enforcement. EPA Region V—Illinois, Indiana,
Michigan, Minnesota, Ohio and Wisconsin—recently cited several facilities for violations of New Source Performance Standards (NSPS), 40 CFR Part 60, Subpart UUU. In the
SAND RECLAMATION BASICS
Thermal sand reclamation offers many benefi ts for metalcasters. These include the ability to dramati- cally reduce the purchase of newly mined sand as well as landfi lling spent sand as waste. It eliminates the need to store mounds of spent sand onsite as it awaits disposal or, in some cases, reuse, most often in construction. Lower freight and disposal costs also offset the cost of energy used for thermal reclama- tion. Casting operations with these machines have reported additional perks such as a lower need for sand additives to prevent casting defects. Sand can be reclaimed in three ways: mechanical, wet or thermal. The optimal result is sand with a grain size distribution comparable to new sand, the removal of all undesired material particles, the elimination of binder coatings and the reduction of fi nes to an acceptable level. While wet reclamation
32
Thermally reclaimed sand (bottom), is shown with new sand (left) and spent sand (right).
is an effective method for cleaning spent green sand, which is bonded with bentonite clay, the need for high volumes of water and the requirement to treat and clarify the water afterward can be a hindrance. Mechanical reclamation is suffi cient for sand that is to be reused for green sand molds, but it does not produce a sand clean enough for use in coremak- ing or nobake molding. To achieve the greatest effi ciency, a combination of ther- mal and mechanical reclamation is used for spent green sand. Chemically bonded sand in nobake operations requires only thermal processing for reuse. Thermal units are either gas fi red or electrical, and the temperature is
maintained at a level to ensure the binders are removed without bonding to the sand particles. The fi nes and other waste par- ticles are accumulated in dust collectors and disposed, and the reclaimed sand returns to the mixer on the molding line.
second half of 2010, two metalcasters in Wisconsin were cited for failing to notify EPA about thermal sand reclaimers installed in the 1990s and the applicability of Subpart UUU. An Indiana metalcaster was cited in July 2011 and an Ohio facility was cited in June 2012. T e facilities were required to comply, in one case to perform a stack test and conduct daily visible emissions readings, as well as develop and implement a corrective action
Page 1 |
Page 2 |
Page 3 |
Page 4 |
Page 5 |
Page 6 |
Page 7 |
Page 8 |
Page 9 |
Page 10 |
Page 11 |
Page 12 |
Page 13 |
Page 14 |
Page 15 |
Page 16 |
Page 17 |
Page 18 |
Page 19 |
Page 20 |
Page 21 |
Page 22 |
Page 23 |
Page 24 |
Page 25 |
Page 26 |
Page 27 |
Page 28 |
Page 29 |
Page 30 |
Page 31 |
Page 32 |
Page 33 |
Page 34 |
Page 35 |
Page 36 |
Page 37 |
Page 38 |
Page 39 |
Page 40 |
Page 41 |
Page 42 |
Page 43 |
Page 44 |
Page 45 |
Page 46 |
Page 47 |
Page 48 |
Page 49 |
Page 50 |
Page 51 |
Page 52 |
Page 53 |
Page 54 |
Page 55 |
Page 56 |
Page 57 |
Page 58 |
Page 59 |
Page 60