HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS		QUICK SEARCH:   [advanced] Author: Keyword(s): Year:  Vol:  Page:

This Article Full Text (PDF) Alert me when this article is cited Alert me if a correction is posted Services Similar articles in this journal Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via Google Scholar Google Scholar Articles by Berigari, M. S. Articles by Al-Any, F. M. S. Search for Related Content PubMed Articles by Berigari, M. S. Articles by Al-Any, F. M. S. Agricola Articles by Berigari, M. S. Articles by Al-Any, F. M. S.

Gypsum Determination in Soils by Conversion to Water-Soluble Sodium Sulfate

11449 S. St. Louis, Ave., Chicago, IL 60655

F. M. S. Al-Any

Talib M. Sa'id & Brothers Co., Jordan Square, Baghdad, Iraq

* Corresponding author.

ABSTRACT

Precise and accurate determination of gypsum in soils has been difficult by the wet-chemical methods, based on its solubility in water. In this work, 2-g samples of three Typic Gypsiorthids were washed once with 25-mL portions of 50% (v/v) ethanol to selectively remove nongypsic soluble sulfates. Soil gypsum was subsequently converted to CaCO₃(s) and Na₂SO₄ by ultrasonic dispersion of the samples twice with 25-mL increments of 0.5 M Na₂CO₃ solution. The SO^2–₄ in the supernatant solution was centrifuge separated and analyzed by the standard gravimetric BaSO₄ (A) and turbidimetric (B) methods to obtain the gypsum content of the samples. The agreement between the data of Methods A and B was excellent where the best-fitted regression line coincided with the 1:1 line in a scattergram. Soil gypsum was also extracted with water, then determined by turbidimetric SO^2–₄ (C) and the Bower-Huss conductometric (D) methods for comparison. Statistical analyses of the data showed higher values (P = 0.05) of gypsum in soils obtained by the proposed method than by water extraction even when the same method of SO^2–₄ analysis was applied. The efficiency of the proposed method was 25 to 31 times greater than that achieved by water. The proposed method of gypsum extraction and its determination in soils from turbidimetric SO^2–₄ analysis was applied. The efficiency of the proposed method was 25 to 31 times greater than that acheived by water. The proposed method of gypsum extraction and its determination in soils from turibidimetric SO^2–₄ analysis is simple, rapid, and quite accurate for soil taxonomy, land reclamation, and other engineering purposes.

Received for publication December 4, 1989.