Products and Patents Applications

Process for preparation of low ferric alum from waste or low grade aluminium dross

Principal Investigator : Dr. Upendra Singh,Dr J.Mukhopadhyay and P Bandopadhyaya & Binuta Patra
With an objective of utilizing low grade (waste) Aluminium dross to extract value added product such as low ferric alum. In the present investigations, various important aspects of preparation of low ferric alum from aluminium dross have been studied. Metallic Aluminium content in low grade dross was found to be around 15-20 % which is difficult to recover economically by conventional methods. The same dross in fine powder form after sieving was utilized to recover low ferric alum by chemical leaching process. The physicochemical characteristic of lab prepared alum was found to have close resemblance to the alum produced by conventional sources. The alum produced from dross would be much cheaper as compared to the alum commercially available in the market. The present study has a scope of internal generation of alum from low grade dross.

Process for preparation of glass ceramic tiles utilizing red mud as the main base material

Principal Investigator : MT.Nimje, Mohamed Najar P.A., M.J.Chaddha, J.Mukhopadhyay and B K Satpathy
A process for making glass ceramic tiles by means of dry mixtures of red mud waste from the alumina refinery, fly ash and glass forming agents is developed for its utilization in building and construction applications. The process involve melting the dry mix with some quantity of glass former along with nucleating (colouring) agents for promoting required crystallization at an elevated temperature around 1100-1300°C and poured to a required mould. The resultant product, glass from the mould is then subjected for suitable heat treatment process for converting glass into glass-ceramics tiles at around 700-850°C. The annealing of glass-ceramics tiles is carried out to release the internal stresses of the product. The glass-ceramic products thus formed show comparable wear and abrasion resistance as well as pleasing colour and visual appearance. Acceptable commercial demand is expected for its use as wall tiles, floor tiles and decorative tiles/product in the building and constructional fields.

Process for preparation of light weight Foamed bricks (LWFBs) utilizing red mud and fly ash

Principal Investigator : Mohamed Najar P.A., MT.Nimje, M.J.Chaddha, J.Mukhopadhyay and B K Satpathy.
A process for making light weight foamed bricks encompassing dry mixtures of red mud and fly ash admixture is developed for construction application such as: partition wall, false wall etc. which are light weight and portable. Homogenized wet slurry of the dry mixture is prepared with the addition of water and foaming agents comprising mixture of 0.25 - 1.5 % nonferrous metal powder and 0.05 - 2.0 % alkali for forming self expanding bricks in brick making moulds. The foamed porous bricks were dried either at room temperature at 80 - 100 0C or in hot air. The bricks were fired at a temperature range 850 – 1100 0C for about 2hrs for curing and conditioning. The light weight foamed bricks (LWFBs) so obtained was subjected for cutting and figuring in to a desired size for building and constructional applications.

Liquidus /Superheat Temperature Measurement System for Molten Cryolite Bath

Principal Investigator : R.J. Sharma, VK Jha & Binuta Patra, Partha Bandopadhyay
A method and apparatus for accurately measuring superheat in an aluminium smelting bath, in which a reusable thermocouple is used to determine the bath temperature and superheat temperature. The system comprises of a thermocouple arrangement in a trolley specifically adapted for efficient use in aluminium electrolysis bath, wherein the trolley is designed in such a way that operation of the apparatus is very easy without using much automation and allowing the reuse of thermocouple and crucible leading to a very economical measurement. The system further comprises software specifically adapted for the acquisition of temperature data from the thermocouple used for the measurement, wherein the software gives online time-temperature plot and also gives liquidus and operating temperature, and wherein the system completes one measurement in 1-2 minutes; and wherein alarms are used to maximize the thermocouple life. Said thermocouple comprises a nickel-chromium-iron alloy (Inconel 600) sheath, which can be reused for 50-60 measurements.

Controlled heat treatment process for destruction of leachable toxic cyanide in first cut SPL (Spent pot lining)-carbon portion

Principal Investigator : MT Nimje, Mohamed Najar P.A. and Binuta Patra
A process for treatment of cyanide containing first cut aluminium spent pot-lining materials (SPL) is illustrated. In particular a selective heat treatment method for destruction of leachable toxic cyanide in SPL is developed for the recovery and safe utilization of carbon as fuel supplement. Chunks of SPL samples collected from discarded aluminium electrolytic cells were crushed, classified (-1.0 + 0.5 mm), and homogenized. The heat treatment process was carried out on homogenized SPL sample at various temperatures ranging from 200-450 °C in a specially designed laboratory scale rotary kiln furnace. A proportionate increase in the destruction of leachable cyanide with increases in temperature was observed. The temperature range 375-425°C with 25-35 minutes of heating time was found optimum for the selective destructions of more than 98% cyanide with 1.6-1.7% reduction in weight of heat treated SPL carbon. The gases evolved during heat treatment process were identified as ammonia, carbon dioxide and nitrogen.