Bram L, Klemetsrud B. Calcium Carbonate in Waste Flooring for Neutralization of Acid Rock Drainage.
Mine Water Environ 2023;
42:70-77. [PMID:
36819894 PMCID:
PMC9925920 DOI:
10.1007/s10230-023-00926-6]
[Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 07/29/2022] [Accepted: 01/24/2023] [Indexed: 06/18/2023]
Abstract
Acid rock drainage (ARD) was successfully neutralized in this study using carpet tiles. Most polyolefin-based carpet tiles contain over 65% of finely ground calcium carbonate (CaCO3) powder by weight in the compound-blended and extruded backing structure; therefore, using them for neutralization is an innovative way to reuse a difficult-to-recycle complex and abundant product. The overall neutralization efficiency potential was calculated at 40% based on the density, purity, and surface images that display the domains of CaCO3 on the tiles. The carpet backing increased the mean of proton activity of AMD collected from a single acidic stream point within the Pinkerton Run tributary near Pittsburgh, PA from 3.3 to 6.1 over the span of four hours in batch-method experiments at CaCO3 loading levels of 0.1 g/L and overall surface area exposure of 229 mm2/mL. Hot acidity levels decreased from 90 to less than 10 mg CaCO3/L, and below detection limits after 20 h of neutralization. The treated and neutralized AMD sample contained 80 mg/L more calcium than the untreated, non-neutralized control, demonstrating the dissolution of CaCO3 from the carpet tile.
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