New Delhi: CSIR-Advanced Materials and Processes Research Institute (AMPRI) has developed red mud, a mineral waste, into X-ray shielding tiles in a green and economically viable manner. The shielding tiles are built through a ceramic route by adding a certain weight percentage of high Z material and binder with it.
The 12 mm thick tiles possess an attenuation equal to 2.1 mm lead at 100 kV. The developed tile has a flexural strength of 34 N/mm2 and a breaking strength of 3369 N. These tiles can be used to build radiation shielding structures in diagnostic X-rays, CT scanner rooms, Cath labs, bone mineral density, dental X-rays, etc., instead of the toxic lead sheet to protect the public from radiation hazards.
The first flyer of the brochure, detailing the development to deployment technology of the mineral waste-made tiles, was released on Saturday by director general, Council for Scientific and Industrial Research (CSIR) N Kalaiselvi at the directors’ conference held at Palampur.
The know-how for the fabrication of “Lead-Free X-ray Shielding Tiles” was transferred to M/S Prism Johnson Ltd., on June 10, 2019 at CSIR, New Delhi. CSIR-AMPRI and M/s Prism Johnson Ltd., have worked together and upscale this technology from the lab to the industry level, and joint-free X-ray shielding tiles (30x30x1.2 cm3) were made on a pilot scale on April 14, 2022.
The developed tiles are tested and approved by the Atomic Energy Regulatory Board (AERB) of India. The product is commercialized and the first instalment has been initiated at INS Kattabomman, Tamilnadu.
Red mud (RM) is the waste generated in the Bayer process of alumina production from bauxite. It is also known as bauxite residue. RM is defined as a “high volume low effect waste”. Nearly 1 to 1.5 tonnes of RM is being generated while producing one tonne of alumina from the bauxite ore through the Bayer process. It is considered to be toxic due to its extreme alkalinity and heavy element leaching.
Annually about 175 million tonnes of red mud have been generated globally and stored in a specially designed clay-lined pond. Among that India is producing nearly 9 million tonnes of red mud every year. The clay-lined ponds often broke out and pollute soil, groundwater, and air and become fatal for both humans and wildlife.
Red mud is one of the underutilized industrial wastes and getting accumulated over the years due to an increase in alumina production as well as inadequate technologies for its large-scale utilization. Although the scientific community has patented more than 700 applications of red mud, very few of them have reached industries due to high cost, low public acceptance, environmental issues, and limited market.
Noteworthy, only 3-4% of red mud has been utilized by the industries to produce cement, bricks, source of iron ore etc., (i.e. 1-1.5 million tonnes (Mt) for cement production, 0.2–1.2 Mt for iron production and 0.5 -1.0 Mtfor building materials and 0.3 Mt for making pigments, catalyst, ceramics, etc.).The beneficial utilization of red mud is becoming a global issue. The red mud contains 30 – 55% of Fe2O3, which is suitable for attenuating high-energy ionizing radiations like X- and gamma rays.