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This website publishes administrative rules on their effective dates, as designated by the adopting state agencies, colleges, and universities.

Rule 3745-73-01 | Definitions and reference to maerials.


The definitions in this rule apply to this chapter.

(A) "Black liquor" means the spent cooking liquor, composed of a mixture of dissolved lignins and inorganic compounds, which remains after the digestion of wood chips in the Kraft pulping process.

(B) "Black liquor solids" means the dry solids which enter the recovery furnace in the black liquor.

(C) "Condensate stripper system" means a system in which total reduced sulfur gasses, partially dissolved in the digester and multiple effect evaporator off-gas condensate, are stripped by means of a countercurrent flow of air or steam in multi-stage columns.

(D) "Digester system" means any continuous or batch process in which white liquor is used to cook the wood pulp, and includes any associated flash tanks, blow tanks, chip steamers and condensors.

(E) "Kraft pulp mill" means a wood pulping mill which uses an alkaline sulfide solution containing sodium hydroxide and sodium sulfide (white liquor) in the wood digesting process.

(F) "Lime kiln" means a unit used to calcine calcium carbonate, commonly known as "lime mud," into calcium oxide, commonly known as "quicklime."

(G) "Multiple-effect evaporator system" means the multiple-effect evaporator including any associated condensors and hotwells used to concentrate the black liquor.

(H) "Recovery furnace" means a straight Kraft recovery furnace including any direct contact evaporators, designed to recover chemicals necessary for the pulp cooking process through the combustion of black liquor containing less than seven per cent liquor such as neutral sulfite semichemical from a soda-based semichemical pulping process on a quarterly basis.

(I) "Smelt dissolving tank" means a vessel used for dissolving smelt from a recovery furnace.

(J) "Soda-based semichemical pulping operation" means any operation in which pulp is produced from wood by cooking or digesting wood chips in a soda-based semichemical such as neutral sulfite semichemical.

(K) "Total reduced sulfur" means the sum of the sulfur compounds hydrogen sulfide, methyl mercaptan, dimethyl sulfide and dimethyl disulfide, that are released during the Kraft pulping operation and measured by methods specified in rule 3745-73-04 of the Administrative Code.

(L) Reference to materials. This chapter includes references to certain matter or materials. The text of the referenced material is not included in the rules contained in this chapter. Information on the availability of the referenced materials as well as the date of, or the particular edition or version of the material is included in this rule. For materials subject to change, only the specific versions specified in this rule are referenced. Material is referenced as it exists on the effective date of this rule. Except for subsequent annual publication of existing (unmodified) Code of Federal Regulation compilations, any amendment or revision to a referenced document is not applicable unless and until this rule has been amended to specify the new dates.

(1) Availability. The referenced materials are available as follows:

Code of Federal Regulations (CFR). Information and copies may be obtained by writing to: "Superintendent of Documents, Attn: New Orders, P. O. Box 371954, Pittsburgh, PA 15250-7954." The full text of the CFR is also available in electronic format at The CFR compilations are also available for inspection and use at most public libraries and "The State Library of Ohio."

(2) Referenced materials:

40 CFR Part 60, Appendix A consisting of appendicies A-1 to A-8; "Test Methods 1 through 30B;" as published in the July 1, 2020 Code of Federal Regulations.

Last updated June 17, 2021 at 8:48 PM

Supplemental Information

Authorized By: 3704.03(E)
Amplifies: 3704.03(A), 3704.03(E)
Five Year Review Date: 6/17/2026
Prior Effective Dates: 11/1/1984, 1/3/1991, 3/30/2006, 2/11/2011, 8/25/2016