Iron-Oxide Pigments Obtained from Sewage Sludge: Properties, Structure, Phase Transformation

摘要

The paper presents chemical, physical, and physicochemical investigations of sewage sludge and iron-oxide pigments produced therefrom. Gravimetric, X-ray phase, and thermal analyses and scanning electron microscopy were carried out in certified laboratories. Experimental results are given for iron-containing sewage sludge produced by the water-treatment plant and taken from water collection filters of Tomsk groundwater sources. It is shown that at heating iron-containing sewage sludge up to 800 eC, a brick-red pigment is formed having the specific surface area of 9.8 m~2/g that corresponds to the theoretical particle size of 124 nm. A flow-chart is suggested for the production of iron-oxide pigments obtained from sewage sludge, and the raw material compositions are designed for construction industry applications. The suggested cement-sand colored compositions of materials and products have passed the evaluation tests at OOO Akvatom (Tomsk, Russia), and their high service properties (strength, water- and frost-resistance) are experimentally supported.