New fired bricks based on municipal solid waste incinerator bottom ash

Eco-Friendly Fired Brick Produced from Industrial Ash and Natural Clay: A Study of Waste Reuse

Bottom ash (BA) is an industrial solid waste formed by the burning of coal. The environmental problems and storage costs caused by this waste increase with every passing day. In this study, the use of BA as an additive (clay substitute) in fired brick production was investigated. The study consisted of two stages. In the first stage, cylinder blocks were produced from clay used in brick production. The second stage was the examination of the experimental substitution of clay with 10, 20, 30 and 40% BA. Samples were fired at 900, 1000, 1100 and 1150 °C to produce fired brick samples. The unit weight, compressive strength (before and after freeze-thawing) and water absorption were analyzed for the samples. The unit weight values decreased in the samples containing BA. The mechanical properties met the conditions prescribed in the relevant standards; i.e., all of the samples fired at 1100 and 1150 °C had a sufficient compressive strength over 20 MPa. The high potential of fired bricks for the construction industry was proved. BA can be used as a clay substitute, while the developed protocol can be used to effectively produce fired bricks.

Lightweight aggregate obtained from municipal solid waste incineration bottom ash sludge (MSWI-BAS) and its characteristics affected by single factor of sintering mechanism

To solve the disposal problem of municipal solid waste incineration bottom ash sludge (MSWI-BAS), using it as the main raw material to prepare lightweight aggregates (LWA) for resource utilization. Sintering is an important process to achieve the desired microstructure and material properties. This paper investigates the characteristics of LWA affected by single factor of sintering mechanism (sintering temperature, heating rate and soaking time). Results show that sintering temperature increased from 1130°C to 1160°C caused high-density microstructure materials gradually formed in LWA, leading to particle strength increased from 0.1 MPa to 3.64 MPa, particle density showed an overall upward trend, reaching a maximum of 916 Kg/m³ at 1160°C, and 1 h water absorption reduced from 68% to 25%. The heating rate of 15 K/min was beneficial to the formation of dense phase structure which could increase the particle strength, and the water absorption rate reached the lowest at this time, while the particle density was less affected by heating rate. When soaking time extended from 5 min to 20 min, particle strength and compressive density were gradually increased, and 1 h water absorption showed an overall downward trend, indicating that a longer soaking time was not conducive to the retention of pores. This study demonstrates that the utilization of MSWI-BAS to make high-performance LWA is feasible, along with the preferable environmental and economic benefits.Implications: MSWI-BAS were selected to produce lightweight aggregate (LWA), so that the sludge disposal problem is reduced. The effects of sintering temperature, heating rate and soaking time on the characteristics of LWA were investigated. Compact glass structures are formed at 1150°C and 1160°C which greatly improve the strength. The heating rate has little influence on the physical properties of LWA products. The particle density of LWA increases after the sintering soaking time reaches 15 minutes.