Regeneration of heavy metal contaminated soils for cement production by cement kiln co-processing
Journal
Resources, Conservation and Recycling
Journal Volume
176
Date Issued
2022
Author(s)
Abstract
Co-processing is considered as an effective way to reduce the cost and environmental footprints for cement production by replacing fuel or raw materials with wastes. In this study, we investigated the influences of co-processing of heavy metal-contaminated soil in cement kiln on the engineering integrity and heavy metal leachability of cement powders and cement mortars. The replacements of the contaminated soil were set at 0, 3.0, 7.6, and 10.0 wt.%. Engineering integrity of the cement products was verified first using typical performance tests, followed by three heavy metal leaching tests, namely Toxicity Characteristic Leaching Procedure (TCLP), EDTA-mediated TCLP and Synthetic Precipitation Leaching Procedure (SPLP). The results showed that in TCLP, only Cr was the concern, in which leachates of cement powders produced by co-processing with > 7.6% soils exceeded the TCLP Cr limit (5.0 mg/L), whereas all leachates of cement mortars met the regulations. EDTA-mediated TCLP could potentially release higher Cr concentrations, indicating that cautions were still needed when applying the cement products in harsh environments. Preliminary economic assessment indicated that using co-processing to treat heavy metal-contaminated soils can bring benefits for both cement industry and soil polluter. Overall, cement kiln co-processing could be an attractive alternative for the remediation of heavy metal-contaminated soil to revive the contaminated site and reduce the environmental impacts of cement production. ? 2021
Subjects
Cement kiln
Co-processing
Environmental compatibility
Heavy metal-contaminated soil
Contamination
Heavy metals
Kilns
Leaching
Mortar
Powder metals
Precipitation (chemical)
Remediation
Soil cement
Soil conservation
Soil pollution control
Soils
Cement mortars
Cement powder
Cement production
Cement products
Coprocessing
Heavy metal contaminated soils
Leachates
Toxicity characteristics leaching procedures
Soil pollution
cement
chromium
copper
edetic acid
heavy metal
manganese
zinc
cement (construction material)
environmental impact
leachate
soil pollution
Article
cement industry
concentration (parameter)
controlled study
economics
engineering
leaching
powder
soil pollutant
Type
journal article