This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles

for the
Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.

Designation: C400 − 98 (Reapproved 2013)´1

Standard Test Methods for

Quicklime and Hydrated Lime for Neutralization of Waste
Acid1
This standard is issued under the fixed designation C400; the number immediately following the designation indicates the year of
original adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. A
superscript epsilon (´) indicates an editorial change since the last revision or reapproval.

ε1 NOTE—Corrected erroneous references in 7.4.2.1 and 7.4.3.1 in December 2017.

1. Scope E70 Test Method for pH of Aqueous Solutions With the

1.1 This test method covers the testing of quicklime and Glass Electrode
hydrated lime for use in the treatment of waste acid solutions
and includes the characterization of the liming material and of 3. Terminology
the acid waste. 3.1 Definitions:
3.1.1 neutralization coeffıcient—the number of parts of lime
NOTE 1—When agreed upon by the manufacturer and the purchaser,
this method may be used directly to evaluate the lime requirement for a required to neutralize one million parts by weight of sulfuric
plant waste acid and in the preparation of the lime slurry; the pH, the time, acid solution (1.5 %) to a pH of 4.4 in 30 min (see Note 1).
temperature, and other conditions of treatment may be adjusted to 3.1.2 pH—a measure of the hydrogen ion concentration of a
conform to plant practice. Otherwise the test shall be performed as
described in this method. sample and representing the logarithm of the reciprocal (nega-
NOTE 2—Under some conditions of test the lime requirement may vary tive logarithm) of the activity of hydrogen ions, calculated as
substantially from that indicated by ultimate chemical analysis or by the follows:
use of a determination of available alkalinity by titration to a stoichio-
metric end point. 1
pH 5 log 5 2log~ H 1 !
~H!1
1.2 This standard does not purport to address all of the
safety concerns, if any, associated with its use. It is the where:
responsibility of the user of this standard to establish appro- H+ = activity of hydrogen ions.
priate safety, health, and environmental practices and deter-
mine the applicability of regulatory limitations prior to use. 4. Significance and Use
1.3 This international standard was developed in accor-
4.1 Since all limes and waste acid solutions are different,
dance with internationally recognized principles on standard-
this test method evaluates the relative quantity of a given lime
ization established in the Decision on Principles for the
needed for the neutralization of a specific quantity of acid.
Development of International Standards, Guides and Recom-
mendations issued by the World Trade Organization Technical 4.2 Liming materials have a specific basicity factor or
Barriers to Trade (TBT) Committee. measure of alkalinity which can be used for comparing their
relative neutralizing power. It avoids dependence on chemical
2. Referenced Documents analysis and is determined as grams of calcium oxide equiva-
lents per kilogram of liming material.
2.1 ASTM Standards:2
C50 Practice for Sampling, Sample Preparation, Packaging, 4.3 Likewise, specific waste acids have an acid value that
and Marking of Lime and Limestone Products can be expressed as grams of hydrochloric acid equivalent per
litre of acid waste. This value is related on a stoichiometric
basis to lime neutralization requirements of a liquid acid waste.
1
These test methods are under the jurisdiction of ASTM Committee C07 on
5. Apparatus
Lime and Limestone and are the direct responsibility of Subcommittee C07.05 on
Chemical Tests. 5.1 pH Measuring Apparatus, conforming to the require-
Current edition approved July 1, 2013. Published August 2013. Originally
ments of Section 5, Apparatus, and Section 6, Reagents and
approved in 1957. Last previous edition approved in 2006 as C400 – 98 (2006).
DOI: 10.1520/C0400-98R13E01. Materials, of Test Method E70. A time-pH recording device or
2
For referenced ASTM standards, visit the ASTM website, www.astm.org, or attachment is desirable but not required.
contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM
Standards volume information, refer to the standard’s Document Summary page on 5.2 Analytical Balance, capable of reproducing results
the ASTM website. within 0.005 g.

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 C400 − 98 (2013)´1
5.3 Stirrer, motorized, capable of rotating at speeds from as a function of grams of lime per 1000 g of H2 SO4 (1.5 %),
120 to 600 r/min. with particular emphasis in the region of pH equals 4.4.
5.4 Miscellaneous Equipment—Chemically resistant 7.4 Results:
glassware,3 metal stands for support of the equipment, etc. 7.4.1 Neutralization Rate Curves:
7.4.1.1 Plot pH versus time in minutes for each of the
6. Purity of Reagents lime-acid ratios used in the initial series of tests. This family of
6.1 Reagent grade chemicals shall be used in all tests. curves serves as the basis for calculation of the lime require-
Unless otherwise indicated, it is intended that all reagents shall ments.
conform to the specifications of the Committee on Analytical 7.4.2 Lime Requirement Curve:
Reagents of the American Chemical Society, where such 7.4.2.1 Plot the pH in 30 min, as determined from the
specifications are available.4 Other grades may be used, pro- neutralization rate curves described in 7.3.2, against grams of
vided it is first ascertained that the reagent is of sufficiently lime used per 1000 g of H2SO4 (1.5 %).
high purity to permit its use without lessening the accuracy of 7.4.3 Neutralization Coeffıcient:
the determination. 7.4.3.1 Interpolate the quantity of lime required to achieve a
6.2 Unless otherwise indicated, references to water shall be pH of 4.4 in 30 min from the lime requirement curve (7.3.2),
understood to mean distilled water. correct for the actual acid concentration, and calculate as parts
of lime required per million parts of H2SO4 (1.5 %) as follows:
7. Test Method A—for Determining Lime Requirement for
the neutralization of a standard sulfuric acid or waste acid N 5 ~ 1.5/Z ! 3 X 3 1000
solution within a time limit of thirty minutes.
where:
7.1 Reagents: N = neutralization coefficient (see 3.1.1),
7.1.1 Sulfuric Acid, Standard Solution (1.5 6 0.05 %)— X = grams of lime per 1000 g of H2SO4 (1.5 %), and
Thoroughly mix 15.8 g of concentrated sulfuric acid (95 % Z = concentration of the H2SO4 to the nearest 0.005 %, as
H2SO4 ) with water, dilute to 1 L, analyze to within 0.005 % determined by analysis.
H2SO 4, and store in a suitable stoppered bottle.
7.5 Precision and Bias:
7.2 Preparation of Sample: 7.5.1 The precision and bias of this test method has not been
7.2.1 Take samples of quicklime and hydrated lime in determined at this time. Replicate samples are recommended.
accordance with Methods C50.
7.2.2 Quicklime—Weigh a sample of quicklime (2.50 6 8. Test Method B—For Determining Acid Value-Basicity
0.01 g) ground to pass a No. 50 mesh sieve. Add to a 500-mL Factor Relationship
tall-form beaker containing 50 mL of boiling water and
continue to boil for 2 min. Remove from hot plate and continue 8.1 Procedure:
stirring with a magnetic stirrer until the slurry reaches room 8.1.1 Basicity Factor—Weigh 2.804 g 6 1 mg of the sample
temperature (at least 10 min). that has been prepared to pass a No. 100 (150-µm) sieve and
7.2.3 Hydrated Lime—Mix a sample of hydrated lime (2.50 transfer to a 500-mL Erlenmeyer flask containing approxi-
6 0.01 g) with 50 mL of water in a 500-mL tall-form beaker mately 20 mL of cold water. (For quicklime samples, heat to
for at least 10 min. boiling to ensure complete slaking). Add from a buret 100 mL
of 1.0 N hydrochloric acid and stopper with a two-hole rubber
7.3 Procedure: stopper (Note 3). The quantity of acid may be increased or
7.3.1 Place the pH electrodes within the beaker about 1⁄2 in. decreased depending on the equivalent strength of the material
(13 mm) above the surface of the lime slurry sample. Set the being tested. Place the flask on a hot plate and boil for 15 min.
motor stirrer to the highest speed at which splattering or (Glass beads may be added to prevent bumping.) Remove the
immersion of the electrodes does not occur. Measure 250 g of flask from the hot plate and cool in water. Add several drops of
H2SO 4 (1.5 6 0.05 %) into a separate 500-mL beaker. Add this phenolphthalein indicator solution and titrate the excess acid
acid to the sample in a single motion and record the pH as a with 0.5 N sodium hydroxide solution. Calculate the basicity
function of time for a period of 30 min (see Note 1). factor as follows:
7.3.2 Test a second slurry sample using more or less than
250 g of H2SO4 (1.5 6 0.05 %), as indicated by the pH value
observed after 30 min reaction in the first test. Repeat the Basicity factor 5 @ ~ V 1 N 1 2 V 2 N 2 ! /W # 3 0.02804
procedure at least four times or until sufficient data are where:
available to give a family of curves that indicate pH at 30 min V1 = HCl (mL) required for titration of the sample,
N1 = normality of HCl,
V2 = NaOH solution (mL) required for titration of the excess
3
Borosilicate glass has been found satisfactory for this purpose. acid,
4
“Reagent Chemicals, American Chemical Society Specifications,” Am. Chemi-
cal Soc., Washington, DC. For suggestions on the testing of reagents not listed by
N2 = normality of NaOH solution, and
the American Chemical Society, see “Reagent Chemicals and Standards,” by Joseph W = sample (g).
Rosin, D. Van Nostrand Co., Inc., New York, NY, and the “United States NOTE 3—A water-cooled condenser with a tapered, ground-glass joint
Pharmacopeia.” and a magnetic stir plate may be used during the boiling step.

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 C400 − 98 (2013)´1
8.1.2 Acid Value—Pipet 10 mL of the sample of acidic waste N2 = normality of HCl, and
into a 250-mL Erlenmeyer flask. This quantity may be in- V = sample (mL).
creased or decreased depending on the strength of the acidic
8.1.3 Relationship of Acid Value to Basicity Factor—
waste. Add an excess of 25 to 30 mL of 0.5 N sodium
Calculate the acid value-basicity factor relationship as follows:
hydroxide solution and boil for 3 min. Filter through a small
Büchner funnel with the aid of vacuum. Wash the residue on
the funnel with water. Add several drops of phenolphthalein Acid value
3 0.7691
indicator solution to the filtrate and titrate the excess sodium Basicity factor
hydroxide with 1.0 N hydrochloric acid solution. Calculate acid 5 lime or limestone product ~ kg! per litre of Acidic Waste.
value as follows: NOTE 4—When agreed upon between the manufacturer and the
purchaser, Test Method A may also be used.
8.2 Precision and Bias:
Acid value 5 @ ~ V 1 N 1 2 V 2 N 2 ! /V # 3 0.03646
8.2.1 The precision and bias of this test method has not been
where: determined at this time. Replicate samples are recommended.
V1 = NaOH solution (mL) required for titration of the
sample, 9. Keywords
N1 = normality of NaOH solution, 9.1 acid value; alkalinity; basicity; lime requirement; liming
V2 = HCl (mL) required for titration of the excess NaOH material; neutralization; neutralization coefficient; pH; waste
solution, acid

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