172 05 | 17 H.H. Abo-Almaged 1 , A.F. Moustafa 2 , A.M. Ismail 3 , S.K. Amin 4 , M.F. Abadir 5 Hydrothermal Treatment Management of High Alumina Waste for Synthesis of Nanomaterials with New Morphologies ABSTRACT AUTHOR Kiln rollers’ grind waste powders (KRGW) collected from a ceramic fac- tory are considered a high alumina waste consisting of several phases. The corresponding author, Dr. Hanan Hassan Abo- Almaged, earned her B.Sc. in Chemistry from Cairo University (1990) and her M.Sc. (1994) from Faculty of Science, Cairo University, in Inorganic Chemistry (Ce- ramic Nanotechnology). She received her Ph.D. (2002) in Inorganic Chemistry (Ceramic Nanotechnology and Advanced Materials) from Faculty of Science, Cairo University. She has been working at National Research Centre as a re- searcher since 2003. E-Mail: hanan-202@hotmail.com KEYWORDS: waste management, kiln rollers grind waste, hydrothermal treatment, phase transformation, alumina waste » Interceram 66 (2017) [5] 1. Introduction Waste is defned as any matter (solid, liquid, gas, or mixture) that is un- desirable or an emission, discharged from any process [1]. In this respect, industrial ceramic wastes becoming an increasing problem worldwide. Recently, this problem has been attracting social concern due to the growing amounts of waste despite the measures and precautions taken aiming to control and regulate waste management. Therefore, the need to manage this waste has become an active research feld that is attract- ing various disciplines, such as civil, chemical, and environmental ones. Several attempts have been made to incorporate such wastes in ceramic bodies in order to minimize the wastes produced as well as reserving natural resources. Ceramic wastes are produced as a result of ceramic processing. They can cause soil, air, and groundwater pollution. They can be classifed accord- ing to their source during ceramics processing. The frst class consists of all fred wastes generated by structural ceramics factories that use only red pastes to manufacture their products, such as bricks, blocks, sewer pipes, and roof tiles. The second one consists of all fred waste produced during the fabrication of stoneware ceramics, such as wall and foor tiles. Other wastes include defective products from dinnerware, sanitary ware, etc. [2–3]. Incorporation of as-received ceramic waste was suggested in order to minimize production costs and energy requirements. For example, sever- al studies were conducted to investigate the possibility of incorporating ceramic waste as a substitute for coarse aggregates in concrete [4–5]. In this respect, sanitary ceramic ware wastes were incorporated in con- crete as fne and coarse aggregate. Despite some decrease in strength, the specimens obtained showed superior behavior over the traditional concrete mix [6]. 1 Refractories, Ceramic and Building Materials Department, Inorganic Chemical Industries and Mineral Resources Division, National Research Centre, Dokki, Giza, Egypt. 2 Environmental Impact Assessment Unit & Environmental Monitoring Laboratory Unit, General Administration of Environmental Afairs, Beni–Suef Governorate, Egypt. 3 Industrial Technological Development Sector – Ministry of Investment, Trade and Industry. 4 Chemical Engineering and Pilot Plant Department, Engineering Research Division, Natio- nal Research Centre, Dokki, Giza, Egypt. 5 Chemical Engineering Department, Faculty of Engineering, Cairo University, Egypt. The KRGW was treated hydrothermally at 150 °C for diferent time peri- ods. The hydrothermal method was found to be a very efective method for the management of KRGW in synthesizing new nanomaterials with new morphologies. Raw and treated kiln rollers’ grind waste was char- acterized using XRF, XRD, TEM, BET, DTA, and TGA. TEM of the raw KRGW showed a lamellar crystal structure with diferent shapes and mor- phologies. XRD displayed four diferent phases with a high percentage of mullite and corundum due to the high levels of Al and Si in the raw waste. Treated KRGW exhibited nano-sieves with diferent morpholo- gies consisting of two predominant phases, namely calcium aluminum oxide and corundum. Results indicated that the hydrothermal process assists phase changes, crystal size, and morphology of the KRGW. This modifcation is expected to improve over all properties of KRGW for ef- cient practical applications. In a typical tile production process, tile waste may reach 7 % of the total production. This leads to maximizing waste treatment through re- cycling waste tiles as fne aggregate in concrete, not only to minimize production costs but also to lower the environmental impact of waste dumping. Concrete made with foor tile aggregates showed similar me- chanical properties to limestone concrete, while concrete made with wall tiles as aggregate showed lower mechanical properties [7]. Also, ce- ramic polishing waste was used as a new construction material in paving blocks [8–9]. In the past four decades, roller kilns have become the main fring de- vice in the manufacture of ceramic tiles, as well as several other products such as fat dinnerware, small insulating refractories, and other ware. A roller kiln consists of a set of stationary parallel horizontal rollers spaced at convenient distances and situated in a row along the length of the kiln. One of the environmental problems associated with the operation of such kilns is the periodic need to grind the kiln rollers. These are con- tinuously contaminated by either fowing of glaze from the tile edges or depositions of alkali salts by condensation from vapor phase. Thus,