The high clinkering temperatures, about 2700 degrees F, make it possible to burn almost any fuel once combustion has been initiated. most plants burn coal, and since cyanide dissociates at about 1500 degrees F, the replacement of a small fraction (about 2%) of the coal with SPL is a possible and sensible procedure .

Since From 1984 to 1988, over 13,000 tons of SPL were beneficially used as a fuel supplement and mineralizer in South Carolina cement kilns. At the Alumax of South Carolina aluminum reduction plant, the SPL was crushed, stored safely in a large building, and shipped to the cement plant on an as-needed basis. It was then blended with coal for direct firing into the cement kiln, with the following successful results:
1. Reduction of fossil fuel costs was proportional to BTU content, with a net savings of about $100,000 per year. Fluoride emissions from the kiln stacks was negligible. present in the SPL was absorbed in the cement clinker and recycling system.
2. Cyanide destruction was complete, stack emissions were at background levels, and no leachable cyanides could be detected in the clinker. Production rates, product chemistry, and product quality were not adversely affected.
3.Cyanide destruction was complete, stack emissions were at background levels, and no leachable cyanides could be detected in the clinker.
4.Production rates, product chemistry, and product quality were not adversely affected.
5 . Land disposal of this material was completely avoided.

The March 13, 1989 listing of SPL as a hazardous waste under Subtitle C of RCRA, in the absence of specific rules encouraging beneficial and environmentally sound reuse of wastes, terminated this waste minimization effort, and forced the unnecessary and undesirable practice of land disposal.

CONCLUSIONS

The reuse of SPL in cement kilns is a proven safe and efficient method of beneficially using both its energy value and its valuable constituents. It has the support of industry, state and federal regulators and other concerned environmentalists. The responsible practices that have been followed should be continued without the undue burden of additional regulatory requirements and unreasonable costs. this, which take advantage of a resource and prevent land disposal, should be encouraged, not dissuaded by inflexible regulatory requirements. Prudent efforts such as this, which take advantage of a resource and prevent land disposal, should be encouraged, not dissuaded by inflexible regulatory requirements.