[Code of Federal Regulations]
[Title 40, Volume 8]
[Revised as of July 1, 2002] 
From the U.S. Government Printing Office via GPO Access
[CITE: 40CFR61.51]

[Page 44]
 
                   TITLE 40--PROTECTION OF ENVIRONMENT
 
               CHAPTER I--ENVIRONMENTAL PROTECTION AGENCY
 
PART 61--NATIONAL EMISSION STANDARDS FOR HAZARDOUS AIR POLLUTANTS--Table of Contents
 
            Subpart E--National Emission Standard for Mercury
 
Sec. 61.51  Definitions.

    Terms used in this subpart are defined in the act, in subpart A of 
this part, or in this section as follows:
    (a) Mercury means the element mercury, excluding any associated 
elements, and includes mercury in particulates, vapors, aerosols, and 
compounds.
    (b) Mercury ore means a mineral mined specifically for its mercury 
content.
    (c) Mercury ore processing facility means a facility processing 
mercury ore to obtain mercury.
    (d) Condenser stack gases mean the gaseous effluent evolved from the 
stack of processes utilizing heat to extract mercury metal from mercury 
ore.
    (e) Mercury chlor-alkali cell means a device which is basically 
composed of an electrolyzer section and a denuder (decomposer) section 
and utilizes mercury to produce chlorine gas, hydrogen gas, and alkali 
metal hydroxide.
    (f) Mercury chlor-alkali electrolyzer means an electrolytic device 
which is part of a mercury chlor-alkali cell and utilizes a flowing 
mercury cathode to produce chlorine gas and alkali metal amalgam.
    (g) Denuder means a horizontal or vertical container which is part 
of a mercury chlor-alkali cell and in which water and alkali metal 
amalgam are converted to alkali metal hydroxide, mercury, and hydrogen 
gas in a short-circuited, electrolytic reaction.
    (h) Hydrogen gas stream means a hydrogen stream formed in the chlor-
alkali cell denuder.
    (i) End box means a container(s) located on one or both ends of a 
mercury chlor-alkali electrolyzer which serves as a connection between 
the electrolyzer and denuder for rich and stripped amalgam.
    (j) End box ventilation system means a ventilation system which 
collects mercury emissions from the end-boxes, the mercury pump sumps, 
and their water collection systems.
    (k) Cell room means a structure(s) housing one or more mercury 
electrolytic chlor-alkali cells.
    (l) Sludge means sludge produced by a treatment plant that processes 
municipal or industrial waste waters.
    (m) Sludge dryer means a device used to reduce the moisture content 
of sludge by heating to temperatures above 65  deg.C (ca. 150  deg.F) 
directly with combustion gases.

[38 FR 8826, Apr. 6, 1973, as amended at 40 FR 48302, Oct. 14, 1975]