Introduction
Metso Minerals Industries provides solutions for Flue Gas Desulfurization (FGD) systems, focusing on wet scrubbing methods to control sulfur dioxide emissions from power plants using high sulfur coals. The document outlines the importance of adhering to strict air quality standards and the role of FGD systems in achieving compliance.

FGD Systems Overview
FGD systems are categorized into regenerable and nonregenerable types. Regenerable systems recycle the desulfurized medium, while nonregenerable systems, which are more common, use lime or limestone to remove SO2, forming calcium sulfate/sulfite compounds. The document emphasizes the need for commercially usable by-products to offset operational costs and reduce waste disposal liabilities.

Limestone Characteristics and Grinding
The sizing of ball mills for limestone grinding is based on tonnage, feed size, product size, and the Bond Work Index, which indicates limestone grindability. The document provides formulas for calculating power requirements and discusses factors affecting grinding efficiency, such as feed size, moisture content, and circulating load.

Metso's Experience and Offerings
Metso Minerals, with extensive experience in FGD systems, offers both ball mills and VERTIMILL™ for limestone grinding. The VERTIMILL™ is highlighted for its energy efficiency and lower operational costs. Metso provides comprehensive services, including design, analysis, and training, to optimize FGD systems.

Control Circuit for Wet Limestone Grinding Systems
The control circuit manages the delivery of ground limestone slurry using manual or automatic systems. Automatic systems utilize PLCs or DCS to regulate operations based on slurry levels, ensuring efficient grinding and product quality.

Metso Slaking Systems
For systems using lime instead of limestone, Metso offers slaking systems that convert lime to milk-of-lime for treating exhaust gases. These systems can utilize either ball mills or VERTIMILL™, with the latter operating in open circuit.

Conclusion
Metso stands ready to support the increasing demand for FGD systems with reliable and cost-efficient equipment, leveraging its extensive experience and technological advancements in grinding systems.