pHPG - pH (pugged clay) Test

A measure of hydrogen ion concentration. This test is only comparative if samples have the same solids percentages and are prepared the same way. If this number is quoted it should specify the % solids in the suspension or solution (e.g. 4.8 @ 10% solids).

The pH of most clay suspensions lies between 4 and 7 indicating they behave as weak acids.

The pH aids you in understanding the amount and type of additives to obtain desired viscosity, especially if producing a slurry. Variation in pH is also a contributor to variation in a pugged body's tendency to soften or stiffen with storage; examination of historical pH data along with observations will indicate direction on compensating by varying water content or additions of epsom salts, vinegar, etc. to the mix.

Variables

VAL - Value (V)

The pH value measured as described in the procedure.

TYPE - Value (V)

This indicates whether the test was done on a sample of POWDER or PUGGED.

Procedure

1. Purpose

This test is designed to measure the pH of a solution prepared from the clay and water used in production each day.

2. Scope

2.1 Test solutions are prepared mid-stream on each production run by the pugmill operator.

5. Procedure

5.1. Take or Make the Sample (Pugmill Operator)

5.1.1. Midway through the run take a 25 gram sample of powdered clay and 100 gram sample of water. Stir clay into water for 1 minute. Set timer for 1 hour.

5.1.2. When timer sounds, dip pH meter into water to immerse the bulb and record the reading in logbook.

5.1.3. Clean meter and container.

5.2. Equipment

5.2.1. Scale for weighing powder sample.

5.2.2. Measuring container for water.

5.2.3. Stiring rod.

5.2.4. Facilities to wash and clean container.

5.2.5. pH meter with calibration solution.

5.2.6. Timer with audible alarm.

5.3. Safety

5.3.1. Do not breathe clay dust unnecessarily.

5.4. Workmanship

5.4.1. Be careful to get a representative sample in the middle of the run.

5.4.2. Use a water sample from the source feeding the pugmill.

Related Information

Links

Typecodes	Body Tests Tests conducted on bodies made from materials, as opposed to the materials themselves.

By Tony Hansen
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