Alkali-activated slag concrete with paper industry waste

Abstract

Pulp and paper manufacturing and recycling industries are a resource-intensive sector, generating 25–40% of the annual municipal solid waste worldwide. Waste includes abundant volumes of paper sludge, as well as the product of its incineration, namely paper sludge ash. These two waste materials are both predominantly landfilled. There is thus a drive for additional valorisation routes for these materials. This short communication focuses on the potential use of paper sludge ash in alkali-activated cement concrete; this type of concrete was estimated to potentially reduce CO2 emissions by up to 5–6 times, while it can also incorporate waste materials or industrial by-products in its composition. The paper presents a laboratory study assessing the feasibility of structural alkali-activated cement concrete with ground granulated blastfurnace slag (a by-product of steel production) and paper sludge ash. Paper sludge ash is used mainly as a source of Ca(OH)2 in the alkaline activator solution, and secondly as an additional source of aluminosilicates. A number of factors potentially affecting the activation process and the resulting concrete quality were investigated, including different dosage of activators, curing conditions and curing time. Mixes with paper sludge ash in the activator system developed high early concrete strengths at ambient temperatures and maintained adequate strengths for structural concrete. Further mix optimisation and mechanical and durability testing, accompanied by material characterisation, are required to establish the advantages of using this waste material in structural alkali-activated cement concrete.

Synthesis, Characterization, and Dye Removal of ZnCl2-Modified Biochar Derived from Pulp and Paper Sludge

“…By 2020, China’s annual paper-making sludge production is about 12 million tons, mainly through landfill, land use, and incineration. 15 To date, the methods for treating paper mill sludge are combustion landfill, recycling as a component of cement, etc. Some research has been done for using primary paper and pulp sludge (PS, a kind of residue produced in the primary treatment of wastewater from the pulp and paper industry) as a promising raw material of biochar for adsorbing pollutants in wastewater.…”

“…), as well as other inorganic wastes in the process, such as fillers, metal components, sand, etc. By 2020, China’s annual paper-making sludge production is about 12 million tons, mainly through landfill, land use, and incineration . To date, the methods for treating paper mill sludge are combustion landfill, recycling as a component of cement, etc.…”

A Study of Innovative Alkali-Activated Binders for Soil Stabilisation in the Context of Engineering Sustainability and Circular Economy

“…2(b) and 3(a) KOH used as the sole activator at the same percentage as PSA led to higher earlier strengths than PSA. However, after 28 days of curing, PSA activator mix strengths were very close-in several occasions higher-to those of the respective KOH mixes; the latter showed little strength evolution between 7 and 28 days; conversely PSA mixes kept gaining strength in time (this was not expected as according to the Authors' experience, PSA used as an alkali activator of GGBS in concrete cement [43,44] gave instead high early strength gain with less strength evolution in later times; this could however be due to the relatively low PSA content used in the concrete mixes). The strength gains with only 3 to 6% PSA in the mixes were very considerable, namely, (a) for mixes without Na 2 SiO 3 17-20 and 30-60 times higher than that of silt for 7 and 28 days of curing respectively; (b) for mixes with PSA+Na 2 SiO 3 22-62 and 66-74 times higher that of silt for 7 and 28 days of curing respectively.…”

Tribological performance evaluation of slag waste filled phenolic composites for automotive braking applications

“…For example, in the European Union, the cost of storing non‐hazardous solid waste can reach €70 per ton. [ 27 ] Since the current landfilling and stockpiling strategies are impractical, slag handling has become a fundamental problem for slag‐producing organizations and environmental regulators in recent decades. Due to the sector's high concentration, local markets cannot absorb the vast amounts of garbage created at a single spot.…”