OfiTE 152-95 User manual

Calcimeter
Part No. 152-95
Instruction Manual
Updated 1/8/2019
Ver. 4.0
OFI Testing Equipment, Inc.
11302 Steeplecrest Dr. · Houston, Texas · 77065 · U.S.A.
Tele: 832.320.7300 · Fax: [phone] · www.ote.com
©Copyright OFITE 2015

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Intro..................................................................................................2
Description......................................................................................2
Components ...................................................................................3
Safety...............................................................................................4
Setup................................................................................................5
Test Procedure................................................................................6
Creating a Calibration Curve.........................................................8
Maintenance..................................................................................10
Warranty and Return Policy ........................................................ 11
Table of
Contents

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The OFITE Calcimeter is used to determine the amount of Calcium
Carbonate (CaCO3) and Magnesium Carbonate (Dolomite) in a sample of
alkaline earth carbonates such as oil well cores or drilled cuttings. Calcite
build up in drilling uids and in water treatment processes causes scaling
problems. Data from the OFITE Calcimeter can help determine the proper
chemical treatment.
This instrument complies with the ASTM D 4373 - 84 (Reapproved 1990)
Standard Test Method for Calcium Carbonate Content in Soils. This test
method is under the jurisdiction of ASTM Committee D-18 on Soil and
Rock and is the direct responsibility of Subcommittee D -18.13 on Marine
Geotechnics, published July 1984.
In the OFITE Calcimeter, calcium carbonate and magnesium carbonate are
reacted with 10 percent hydrochloric acid in a sealed reaction cell to form
CO2. As the CO2is released, the pressure build up is measured using either
a pressure gauge or a pressure recorder. During the calibration process,
a calibration curve is created by reacting HCl with pure, reagent-grade
CaCO3. By using a known weight of CaCO3reagent, you can determine
the relationship between the amount of pressure released and the weight
of CaCO3in the sample. Since all reaction cells are slightly different, this
relationship will be different for each cell. Therefore a calibration curve is
required to obtain accurate results.
The calcium carbonate content of soil (ASTM Procedure D 4373) is
determined by treating a 1 g dried soil specimen with HCl in the reactor
cell. The resulting pressure increase is then measured and compared to the
calibration curve to determine the total weight of CaCO3in the test sample.
Intro
Description

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Components #142-54 O-ring for Bleed-Off Screw
#152-95-1 Gauge with Cover, 30 PSI, 4" Diameter
#152-95-2 Bleed-Off Screw
#152-95-3 Cell Cap
#152-95-4 Reaction Cell
#152-95-5 O-ring for Cap
#152-95-6 Sample Cup
Optional:
#152-96-6 Mortar, 65 mL, Porcelain
#152-96-7 Pestle, Porcelain
#153-02 Brush, Graduate, 1.5" × 10.75"
#153-18 Graduated Cylinder, 10 mL × .2 mL, Glass
#153-55 Stopcock Grease, Silicone
#166-03 Hand-held Balance, 0 - 320 g × .1 g
#275-03 Hydrochloric Acid, 10%, 8 oz UN 1789
#285-00-1 Calcium Carbonate, 100 g

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Safety The Calcimeter test relies on the reaction of CaCO3with hydrochloric acid.
Hydrochloric acid is corrosive and may cause chemical burns. Use care in
handling the acid. Avoid contact with skin, eyes, and clothing. In the event
of exposure to skin or eyes, immediately ush with large quantities of water
for at least 15 minutes. Do not inhale vapors. Process hydrochloric acid
beneath a laboratory hood or in a well-ventilated area to reduce the risk of
inhalation. Wear appropriate safety equipment at all times.
Do not take internally. In the event of accidental exposure, get medical
attention immediately.
Refer to the Material Safety Data Sheet (MSDS) for more information on
Hydrochloric Acid

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Setup Begin by carefully unpacking the equipment. Inspect each piece to ensure
everything is clean and in good operating condition. Inspect the cell cap
o-ring for cracks or wear.
Gauge
Cell Cap
Bleed Valve
O-ring

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Test
Procedure
Before starting the test procedure, make sure the equipment is clean and in
good operating condition. Verify that a calibration curve is available for the
particular equipment to be used. If a calibration curve is not available, see
the “Creating a Calibration Curve” section on page 8 to construct one.
1. Obtain a sample of core, drilled cuttings, or other solids that are to be
analyzed. The sample should be dry and free of contaminants. Grind the
sample to 100 mesh or ner, using a mortar and pestle and a 100-mesh
sieve. If you do not know whether the sample has been dried, heat it in
an oven at 220°F (105°C) for 12 to 24 hours.
2. Weigh approximately 1.0 - 1.4 g of the sample to the nearest .001 g.
3. Load the test sample in the reactor cell.
a. Unscrew and remove the cell cap. Remove the acid cup from the
reaction cell.
b. Inspect the reaction cell and top. Make sure both are clean and dry.
c. Make sure the reaction cell o-ring on the top and the o-ring on the
bleed valve are in good condition. Use a light coating of vacuum
grease on the o-ring seals. Make sure all pipes or tubing connections
are tight and do not leak.
d. Hold the reaction cell in a horizontal position and slide one piece of
paper and its sample to the bottom.
e. Return the cell to the vertical position and brush the paper with a
small brush to remove traces of the sample, then remove the paper.
f. Fill the acid cup with 20 mL 10% hydrochloric acid. Carefully place
the cup into the cell. Be careful not to spill the HCl or get any on the
bottom of the cup.
g. Hand tighten the cell cap. Be careful not to splash any acid onto the
sample.
h. Open the bleed valve until the pressure reading is zero. Then close
the bleed valve tightly.
i. Turn the cell back to the horizontal position to release acid from the
cup.
4. Turn the reaction cell back to vertical and start timing the test. This will
start the reaction between the HCl and the CaCO3.

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5. At 30 seconds, record the pressure as “CaCO3Pressure”. If the test
sample contains any dolomite, there will be a pause, then a slow, second
rise in pressure. Swirl the reaction cell and allow sufcient time for the
reaction to nish. The reaction is complete when the pressure stops
increasing. This should happen in 30 to 45 minutes. The nal pressure
value is the total CaCO3pressure plus the dolomite pressure. To
calculate the dolomite pressure, subtract the CaCO3pressure (30 second
reading) from the total pressure (30 - 45 minute reading).
6. Refer to the graph below to interpret the pressure readings.
7. Use the equations below to calculate the percentages of CaCO3and
dolomite. For values of “Slope” refer to the “Creating a Calibration Curve”
section below.
%CaCO3=
%Dolomite =
(Pressure Reading, PSI) (100)
(Sample Weight) (Average Slope)
(Total Pressure - CaCO3Pressure) (100) (.92)
(Sample Weight) (Average Slope)

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Creating a
Calibration
Curve
The volume of a calcimeter reaction cell determines the relationship between
the pressure increase and the amount of CO2released. This relationship
is constant for a given reaction cell. The calibration curve and calculated
calibration factor are used to convert the amount of pressure released
into a percentage of calcium carbonate. All points on the calibration curve
represent 100% CaCO3(for that sample weight). Any number of samples can
be used to construct the calibration curve. The following are recommended
for accuracy.
1. Prepare ve sets of duplicate specimens with the following masses of
CaCO3:
0.2 ± 0.01 g
0.4 ± 0.01 g
0.6 ± 0.01 g
0.8 ± 0.01 g
1.0 ± 0.01 g
2. Load a calibration sample.
Perform the procedure outlined in the “Test Procedure”, step 3.
3. Tip the cell and allow acid to run out of the cup onto the sample. Swirl the
cell gently and continuously until a constant pressure is obtained. This
will take at least 10 minutes. Keep the reactants in the lower part of the
cell to avoid getting acid into the pressure gauge or pressure transducer.
As soon as the reaction has started, observe the rapidly rising pressure.
Record the peak pressure to the nearest 0.1 PSI (0.5 kPa) as the CaCO3
pressure for the sample weight used.
If a mechanical shaker is available, it may be used to agitate the cell
rather than swirling the reactants. Agitate the sample for 10 minutes.
4. Repeat steps 2 and 3 for each of the remaining samples you prepared in
step 1.
5. For each sample create a plot on linear graph paper. On the x-axis plot
grams of CaCO3 and on the y-axis plot the nal pressure in PSI. Draw
a straight line through the average of the points. The graph on page 9
shows a sample calibration curve.
6. Because the relationship between pressure and sample size is linear, you
may assume the curve to be a straight line with a constant slope. As the
graph on page 9 illustrates, the slope of the curve is 2 PSI / .1 g CaCO3,
or 20 PSI / 1.0 g CaCO3, resulting in a slope of 20. Therefore, the
calibration factor is .05 × 100 = 5. This number is the slope or average
slope for the equipment. It is a function of the volume of the reaction cell.

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As shown by the equations below, the slope can be written as a “Cell
Factor” to multiply the pressure reading to directly obtain percentages of
Calcium Carbonate and Dolomite.
As described above Slope = 20 PSI for a 1g sample therefore
% CaCO3= = 5 × Pressure
% Dolomite =
or
% Dolomite = 4.6 × (Total Pressure - CaCO3Pressure)
Sample Calibration Curve
(Pressure) (100)
(1 g) (20)
(Total Pressure - CaCO3Pressure)(.92)(100)
(1 g × 20)