Council of Scientific and Industrial Research

National Mineral Development Corporation Limited

Haresh Mahipatlal Mody

Hari Chand Bajaj

Jatin Rameshchandra Chunawala

Rajesh Shantilal Somani

Raksh Vir Jasra

Suresh Chandra

Dipti Jivanbhai Barochiya

Hemal Narendrakumar Ranpara

Devendra Lalijibhai Ghelani

Kamlesh Kumar

Pushpito Kumar Ghosh

Maheshkumar Ramniklal Gandhi

Pratyush Maiti

Keshav Rao

Maharaj Kishen Dhar

Himanshu Labhshanker Joshi

Hasina Hajibhai Deraiya

Sumesh Chandra Upadhyay

Upendra Padmakant Saraiya

Dipak Balwantrai Shukla

Maharaj Kishan Dhar

C Kesava Rao

Niraj Rameshchandra Vyas

A method of producing soda ash and ammonium sulphate by recycling by-products of Merseberg and Solvay processes includes treating brine with soda ash distiller waste for desulphatation of the brine to obtain gypsum, recovering pure salt from the desulphated brine and utilizing it in manufacture of soda ash in a Solvay process, washing the gypsum and reacting it with liquor ammonia and carbon dioxide to obtain CaCOand ammonium sulphate, separating the CaCOfrom the ammonium sulphate solution and recovering solid ammonium sulphate, washing the CaCOfollowed by calcination to generate COand lime, recycling the COin the Solvay process to obtain soda ash, recycling the lime with ammonium chloride generated in the Solvay process to recover ammonia and obtain distiller waste containing CaClas a by-product, recycling the by-product distiller waste for the desulphatation of the brine, and recycling the ammonia recovered.

Method of recycling of by-products for the production of soda ash and ammonium sulphate

Kainite mixed salt is treated with water to obtain solid schoenite and a schoenite end liquor. The latter is desulphated using recycled CaCland thereafter evaporated to obtain camallite crystals, from which KCl is recovered, and a liquor rich in MgCl. Gypsum produced during desulphatation is reacted with aqueous ammonia and COto produce ammonium sulphate and calcium carbonate. The calcium carbonate is calcined to obtained CaO and CO. The CaO is slaked and reacted with the MgCl-rich liquor generated above to produce slurry of Mg(OH)in aqueous CaCl. To this surface modifying agent is added while hot and, after cooling, the slurry yields surface modified Mg(OH). The filtrate rich in CaClis recycled for desulphatation process above. The solid surface modified Mg(OH)may he calcined to produced MgO. The schoenite and KCl are reacted to produce solid sulphate of potash.

Process for simultaneous production of potassium sulphate, ammonium sulfate, magnesium hydroxide and/or magnesium oxide from kainite mixed salt and ammonia

The present invention provides a process for the preparation of finely divided precipitated silica. Finely divided precipitated silica is prepared by neutralization of alkali silicate solution, under continuous stirring, at 60&#xb0; to 90&#xb0; C. in presence of alkali metal salt as coagulating agent, in various neutralization steps during which neutralization is interrupted for specific time. Further acidic silica sol, is added until 60 to 80% of total alkali is neutralized. The reaction mixture is then aged at least for 3 minute under continuous agitation, followed by circulation through centrifugal pump at an appropriate rate.

Process for the preparation of finely divided precipitated silica

The present invention provides a process for the preparation of detergent builder Zeolite-A from Kimberlite tailing generated as solid waste during diamond mining is disclosed. The process comprises, reacting an acid treated Kimberlite tailing with alkali solution to obtain sodium silicate and reacting it with alkaline aluminum source at room temperature and crystallizing at higher temperature to obtain Zeolite-A. The product is useful as builder in detergent formulation.

Process for preparing detergent builder Zeolite-A from Kimberlite tailings

In the present invention a process for the preparation of sodium silicate from Kimberlite tailing generated as solid waste during diamond mining is disclosed. The process comprises, reacting Kimberlite tailing with mineral acid to remove acid soluble impurities followed by digesting acid treated Kimberlite tailing with alkali solution in a open or closed system to obtain sodium silicate useful for commercial applications.

Process for the preparation of sodium silicate from Kimberlite tailing

A new process is described for the preparation of free flowing hydrated amorphous silica from kimberlite tailing&#x2014;a waste in diamond mining. The process comprises treating of kimberlite with acid, further reacting it with alkali solution to obtain soluble metal silicate solution, which is subsequently neutralized with mineral acid to polymerize silica as insoluble precipitates. The products is useful in rubber, paints as abrasive etc.

Process for preparing amorphous silica from kimberlite tailing

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Bhavnagar, India

Haresh Mahipatlal Mody