Ulewicz Malgorzata, Jura Jakub, Zieliński Adam, Pietraszek Jacek
Faculty of Civil Engineering, Czestochowa University of Technology, Dabrowskiego 69 Street, 42-201 Czestochowa, Poland.
Łukasiewicz Research Network-Upper Silesian Institute of Technology, 44-100 Gliwice, Poland.
Materials (Basel). 2024 Aug 30;17(17):4295. doi: 10.3390/ma17174295.
The paper presents an analysis of the effective use of a mixture of steel sludge (S1) and slag (S2) from the converter process of steel production for the production of cement mortars. Metallurgical waste used in the research, which is currently deposited in waste landfills and heaps near plants, posing a threat to groundwater (possibility of leaching metal ions present in the waste), was used as a substitute for natural sand in the range of 0-20% by weight of cement (each). The obtained test results and their numerical analysis made it possible to determine the conditions for replacing part of the sand in cement mortars with a mixture of sludge and slag from a basic oxygen furnace (BOF) and to determine the effects of such modification. For the numerical analysis, a full quadratic Response Surface Model (RSM) was utilized for two controlled factors. This model was subsequently optimized through backward stepwise regression, ensuring the inclusion of only statistically significant components and verifying the consistency of residual distribution with the normal distribution (tested via Ryan-Joiner's test, > 0.1). The designated material models are helpful in designing ecological cement mortars using difficult-to-recycle waste (i.e., sludge and converter slag), which is important for a circular economy. Mortars modified with a mixture of metallurgical waste (up to 20% each) are characterized by a slightly lower consistency, compressive and flexural strength, and water absorption. However, they show a lower decrease in mechanical strength after the freezing-thawing process (frost resistance) compared to control mortars. Mortars modified with metallurgical waste do not have a negative impact on the environment in terms of leaching heavy metal ions. The use of a mixture of sludge and steel slag in the amount of 40% (slag/sludge in a 20/20 ratio) allows you to save 200 kg of sand when producing 1 m of cement mortar (cost reduction by approx. EUR 5.1/Mg) and will also reduce the costs of the environmental fee for depositing waste.
本文对钢铁生产转炉过程中产生的钢渣（S1）和炉渣（S2）混合物用于生产水泥砂浆的有效利用情况进行了分析。研究中使用的冶金废料目前被堆放在工厂附近的垃圾填埋场和废料堆中，对地下水构成威胁（废料中存在的金属离子有浸出的可能性），在水泥重量的0-20%范围内（每种废料）用作天然砂的替代品。获得的测试结果及其数值分析使得确定用碱性氧气转炉（BOF）的污泥和炉渣混合物替代水泥砂浆中部分砂的条件以及确定这种改性的效果成为可能。对于数值分析，针对两个控制因素采用了全二次响应面模型（RSM）。该模型随后通过向后逐步回归进行了优化，确保仅包含具有统计学意义的成分，并通过Ryan-Joiner检验（>0.1）验证残差分布与正态分布的一致性。指定的材料模型有助于使用难以回收的废料（即污泥和转炉渣）设计生态水泥砂浆，这对循环经济很重要。用冶金废料混合物改性的砂浆（每种废料含量高达20%）的特点是稠度、抗压强度和抗折强度略低，吸水率也略低。然而，与对照砂浆相比，它们在冻融过程后的机械强度下降较小（抗冻性）。用冶金废料改性的砂浆在重金属离子浸出方面对环境没有负面影响。使用40%的污泥和钢渣混合物（炉渣/污泥比例为20/20），在生产1立方米水泥砂浆时可节省200千克砂（成本降低约5.1欧元/吨），还将降低废料处置环境费用成本。
