[Code of Federal Regulations]
[Title 40, Volume 8]
[Revised as of July 1, 2008]
From the U.S. Government Printing Office via GPO Access
[CITE: 40CFR61.51]

[Page 45-46]
 
                   TITLE 40--PROTECTION OF ENVIRONMENT
 
         CHAPTER I--ENVIRONMENTAL PROTECTION AGENCY (CONTINUED)
 
PART 61_NATIONAL EMISSION STANDARDS FOR HAZARDOUS AIR POLLUTANTS--Table of 
 
            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

[[Page 46]]

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]