Earth, Atmosphere & Environment Sciences

Title :

Reactive Gel-Curing Process for Transforming Environmentally Threatening Industrial Solid Wastes into High Value Building Materials

Area of research :

Earth, Atmosphere & Environment Sciences

Focus area :

Waste to wealth

Principal Investigator :

Dr Anantha Kumar S, Senior Principal Scientist, CSIR-National Institute for Interdisciplinary Science and Technology (CSIR-NIIST), Kerala

Timeline Start Year :


Timeline End Year :


Contact info :


Executive Summary :

Objective: 1. Processing of chemically reactive, water compatible silica-polymer hybrid gels from alumina trihydrate, rice husk silica and acrylic resin for ‘Gel-bonding’ technology. 2. Formulation of hybrid cement mix from fly ash, gypsum, and polymer additive+ fine scale silica sand and alkali activated additives. 3. Pilot scale manufacturing of actual size bricks from silica sand, foundry sand, fly ash and gypsum using hybrid gel bonding technique. 4. Production of 250 L of hybrid gel binders and for pilot scale processing of 500 to 1000 numbers of bricks. Product evaluation and certification by authorized agencies. 5. Manufacturing of light weight, composite pre-fab walls from Cement/fly ash/Gypsum and light weight fly ash aggregates. 6. Documentation of Process know-how and technology transfer on the products like expanded silica aggregates, light weight pre-fab walls, bricks and hybrid cement to the identified user industries.

Summary: Background and Justification: Kerala and Tamil Nadu have more than 700 numbers of clay- tiles and bricks making industries. At present there exists a serious issue of illegal mining of natural clays and sand from where the brick and tile industries procure their raw materials by paying heavy price. In Kerala and Tamil Nadu acute shortage of raw materials is realized due to strict policy by the Government for protecting the natural environment. Therefore, utilization of industrial wastes for brick and tile sector is extremely essential.The conventional clay based bricks and tiles require firewood or oil/gas for firing which adds to CO2 emission. The oil as well as fire wood based firing is presently banned. Due to this, brick and tile industries are finding difficulties in the building materials business. These industries look for alternate raw materials and brick making technologies which do not involve firing and sintering. In this regard, cold bonded technology has greater advantage in terms of process and its impact on the environment. Chemical bonding of building materials from industry wastes is novel and innovative that has great impact on sustainable building materials industries in the country.Proposal: The project aims to employ water compatible chemically reactive, alkali activated alumino-silicate gels as bonding/curing agents for manufacturing bricks. Range of byproducts like phospo gypsum, alumina tri-hydrate, rice husk silica, fine silica sand, foundry sand etc are commonly produced by companies like KMML, English Indian Clays, Pee Kay Steel and Travancore Titanium products in Kerala. They are chemically either acidic or basic and environmentally unsafe. Low cost polymeric dispersants such as acrylic resin, along with reactive alumino-silicate gels can be used to make chemically bonded high strength, high value building materials with different colors. In this project industrial solid wastes such as acidified iorn oxide sludge, copper smelter waste, fine silica sand, fly ash, rice husk ash, rock dust etc., will be converted to high value products like light weight aggregates, pre-fab walls and bricks. Chemically reactive, water compatible gel binder will be produced first from alumina trihydrate and rice husk silica and it will be used for self-reactive bonding of solid wastes. The process and product development leading to technology transfer is the focus of this project.

Organizations involved