Date of Award

1-1-1969

Document Type

Thesis

Degree Name

Master of Science (MS)

Department

Chemical Engineering

Abstract

The utilization of leonardite for the production of granular activated carbons was investigated. In granular activated carbons it is desirable to have hard dense granules to permit use without excessive disintegration. Two methods were used to modify the leonardite structure in order to obtain better granules. In one method the leonardite was put into colloidal suspension with certain alkalis. Chemicals were then added to the suspension. The additives used were calcium hydroxide, phosphoric acid, and calcium carbonate. This material was then granulated by drying. The second method for preparing granules consisted in pelletizing powdered leonardite in a rotary drum using a fine spray of sodium hydroxide solution. The chemical additives used in this method were pitch, zinc chloride and phosphoric acid. These granules were then dried, carbonized and activated. Activation was carried out in a rotary tube furnace using steam as an activating agent. For leonardite char fed at 534 grams per hour the optimal activation conditions for methylene blue adsorption were found to be 950° C. with a steam rate of 300 grams per hour. Methylene blue and heat of wetting tests indicated that leonardite char when activated generally had more adsorptive power than the colloidally prepared carbons and had less adsorptive power than the pelletized carbons. The carbon with the greatest adsorptive capacity was a pelletized carbon with a zinc chloride additive. For methylene blue adsorption it was equal to Darco grade S-51 and about 60 per cent as efficient as Columbia grade G. The hardness and abrasion resistance of the prepared carbon were inferior to that of the commercial carbons.

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