Life cycle assessment of using calcium carbonate in waste flooring for neutralization of acid mine drainage: A comparison study
Publication date: 24 November 2025Publication description: Sustainable Chemistry for the Environment, Volume 13, March 2026, 100302Acid mine drainage (AMD) poses a major environmental pollution issue linked to historical mining sites, frequently necessitating remediation approaches that utilize neutralizing agents. A life cycle assessment (LCA) was performed to analyze the environmental effects of traditional remediation methods compared to the use of downcycled carpet tile waste at a theoretical AMD site. Polyolefin-based carpet tiles can incorporate more than 65 % finely ground calcium carbonate (CaCO3) powder by weight in their compound-blended and extruded backing, presenting a potential novel approach for neutralization by repurposing a complex and abundant material that is difficult to recycle. Six scenarios were examined per the functional unit of one cubic meter of AMD water that consider various remediation construction materials (concrete and plastic liner) and neutralization methods (downcycled carpet tiles and limestone). Three key midpoint impact categories were analyzed: global warming potential (GWP), particulate matter formation potential (PMFP), and total human toxicity potential (HTP), which collectively represented 94 % of the endpoint outcomes. Midpoint results showed that the limestone neutralization that used a plastic lined system had the lowest GWP (1.21E-02 kg CO2 eq), PMFP (5.46E-05 kg PM2.5 eq), and total HTP (3.41E-03 kg 1,4-DCB) per cubic meter of AMD water. On the contrary, the system that used downcycled carpet tile waste in a reinforced concrete tank had the highest 480 % higher GWP, 350 % higher PMFP, and a 428 % higher total HTP. Although this downcycling method may yield higher emissions, it helps extend the lifespan of carpet tiles and reduces the need for additional mining operations.
Geospatial Analysis of the Socioeconomic and Demographic Effects of Historic Coal Mining in the Greater Pittsburgh Region, Pennsylvania, USA
Publication date: 12 September 2024 Publication description: Spatial Demography, Volume 12, article number 7, (2024)A geospatial model was developed to statistically assess the socioeconomic effects of coal mining in the greater Pittsburgh, Pennsylvania area by integrating home sale data, abandoned mine lands (AML) inventory “problem area” sites, and census demographic information. Results indicated that homes located within problem areas sold for an average of 28% ($58,600) less than homes outside of these regions. Demographic data revealed a notable disparity in the population distribution within Allegheny County mining problem areas as having a statistically significant larger Black population. This same trend was even more pronounced in urban areas. The study also established that areas influenced by past mining activities had a higher proportion of individuals without formal postsecondary education. Logistic regression models were created to analytically evaluate the relationship between predictor variables, specifically home sale price and Community Needs Index, to the probability of being situated within mining problem areas. The home sale analysis indicated a negative correlation between sale prices and the likelihood of residing in a mining-affected zone, implying that properties with lower prices are more commonly situated in these impacted areas. The CNI logistic regression model revealed a correlation between the probability of living in a mining problem area and overall higher community needs.
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Calcium Carbonate in Waste Flooring for Neutralization of Acid Rock Drainage
Publication date: 14 February 2023Publication description: Mine Water and the Environment, Volume 42, pages 70–77, (2023)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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POLYOLEFIN BLEND COMPOSITIONS
Patent date: Issued Dec 12, 2019 Patent issuer and number: US WO/2019/240899The supply chain in post-consumer recycle (PCR) products is quite complex and includes several parties which may collect, separate, de-label, grind, wash, re-separate, compound and finally sell to a customer who will fabricate the plastic part. It is common to see greater than 10% of polypropylene (PP) material mixed into a high density polyethylene (HDPE) post-consumer recycle base material. However, the immiscibility tendencies of HDPE and PP create a blend with limited properties. Indeed, the post-consumer recycle rigid high-density polyethylene (HDPE) and polypropylene (PP) industry struggles to balance and maintain needed physical properties, such as impact resistance, of the recycled material. For example, the lack of effective processes to separate PP and HDPE from one another results in a high concentration of one polyolefinic contamination within the other polyolefin. Furthermore, impact modifiers or compatibilizers are typically added to increase properties specified by the industry. However, modifiers typically increase one property of the material (like impact resistance), and do so only slightly (e.g., by 1 kJ/m2 at room temperature). Furthermore, most modifiers also reduce one or more desirable material properties (such as flow modification). There is a need for compositions and methods that can provide compositions having enhanced composition properties such as flow modification and impact properties.
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Waste Flooring Materials for Acid Neutralization and Filtration of Abandoned Mine Drainage
Publication date: Feb 11, 2021 Publication description: Prior Art Database - IP.comAbandoned mine drainage, specifically acid mine drainage (AMD), is a major source of waterway contamination that often leads to (1) highly acidic water with a (2) greater degree of sediment. It occurs when water penetrates into mine cavities, reacts with pyrite, and eventually seeps out of the mine and into the water system. Toxins and low pH levels from AMD can significantly disrupt the environment, ecology, and economy of affected areas. Calcium carbonate (CaCO₃) fillers are frequently added to polyolefin-based flooring products, such as carpet tile backing and resilient flooring, at very high levels (greater than 60%). Such levels of filler in the product demonstrated the ability to successfully neutralize acidic abandoned mine drainage water. Woven regions of soft floor coverings also proved to be effective for sediment particle filtration. Floor coverings account for an enormous volume of municipal solid waste in landfills and are difficult to recycle. Innovative second life uses of multi-layer polymeric floor coverings would allow for the reuse of waste construction materials.
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Polypropylene-based Materials for Improved Processability of Highly-filled Polymers
Publication date: Feb 10, 2021 publication description: Prior Art Database - IP.comComposition of polypropylene (PP), maleated PP, with added low viscosity propylene-based elastomer [e.g. Vistamaxx™ 8880] allows for easier processing of highly-filled glass fiber or mineral filled parts. High-flow LVPBE appears to have allowed the glass fibers to orientate through the die better with less resistance, reducing the surging problem, as seen in the control. Impact strength was increased, while the glass fiber maintains the blend at similar stiffness. The addition of LVPBE also increased the 50% GF PP control MFR by 44% and reduced the torque of the extruder by 30%, showing it provided better processability. SOAS rheology testing confirmed this by determining that complex viscosity decreased by 15%.
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Polyvinyl Chloride (PVC) Free Backing Layer for Flexible Luxury Tile (LT) Flooring Products
Publication date: Jan 21, 2021 Publication description: Prior Art Database - IP.comAt >25% compounded annual growth rate, LT is the most rapidly growing product in the flooring market at the time of this paper. The core of the product most commonly contains a variation of PVC that depends on the targeted stiffness. Oftentimes rigid tiles contain a high percentage of fillers, whereas flexible tiles require a generous use of plasticizers that are mixed with the PVC. Environmental, recycling, and sustainability drivers are pressuring flooring companies to consider PVC free LT. Polypropylene (PP) and propylene-based elastomers (PBE) such as VistamaxxTM with desirable properties were used to create the core/backing layer of flexible LT products and successfully laminated onto PP topsheets. The PBE cores were tested for hardness and flex and benchmarked against commercial tiles with comparable performance.
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Adhesive Formulations Containing VistamaxxTM Polymer
Publication date: Apr 1, 2019 Publication description: Prior Art Database - IP.comThis publication discloses adhesive formulations that comprise of Vistamaxx polymer. Vistamaxx polymer is a propylene base elastomer with up to 20 wt% ethylene in its composition. It is discovered that Vistamaxx resins and other optional ingredients can be dissolved in preferred organic solvents to form an adhesive paste. The adhesive pastes were tested and they worked well with a variety of substrates and particularly well with polypropylene.
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POLYPROPYLENE BASED COMPOSITIONS WITH FIBER GLASS
Publication date: Nov 29, 2018 Publication description: Prior Art Database - IP.comCompositions of polypropylene [PP], maleated PP, hydrogenated hydrocarbon resin [HCR] and glass fibers for stiffer injection molded or extruded parts are demonstrated. A propylene homopolymer (HPP) [e.g. a 35 MFR homopolymer], plus compatibilizer [e.g. Exxelor™ 1020 polymer resin], plus hydrogenated hydrocarbon resin [e.g. Oppera™ PR100A tackifier or Eastman™ R1140 tackifier] plus glass fiber can solve the problems of having processability and maintaining stiffness.
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Vistamaxx™ Performance Polymer in HDPE Converting Processes
Publication date: Sep 13, 2017 Publication description: Prior Art Database - IP.comLLDPE was commercially used as a carrier resin for CaCO3 master batch. In this study, Vistamaxx™ Performance Polymer was used as the carrier resin. The master batch was consequently used to fabricate High Density Polyethylene (HDPE) bottles with 10 wt% CaCO3 fillers. A few Vistamaxx and HDPE grades were studied. The resin and bottle properties including Environmental Stress Crack Resistance (ESCR), impact strength, and top load strength were evaluated. It was discovered that there was an advantage to use Vistamaxx as the carrier resin vs using LLDPE as the carrier resin. PE density was also found a key factor of the property improvement and modifications. Methods to enhance the Vistamaxx benefits were also discovered.
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