Council of Scientific and Industrial Research

Pratyush Maiti

Pushpito Kumar Ghosh

Maheshkumar Ramniklal Gandhi

Jatin Rameshchandra Chunawala

Subarna Maiti

Hari Chand Bajaj

Haresh Mahipatlal Mody

Soumya Haldar

Krishna Kanta Ghara

Rajesh Shantilal Somani

Himanshu Labhshanker Joshi

Hasina Hajibhai Deraiya

Sumesh Chandra Upadhyay

Prasanta Kumar Das

Arup Kumar Siddhanta

Gadde Ramachandraiah

Kamalesh Prasad

Dibyendu Mondal

Harshad R Brahmbhatt

Parimal Paul

Subbarayappa Adimurthy

Suresh Eringathodi

Upendra Padmakant Saraiya

Bharti Gunvantray Shah

Samir Kumar Kanjibhai Charola

Girdhar Joshi

Rajendra Patil

Neha Pratap Patel

Jignesh Solanki

Mallampati Subbareddy

Harshad Raman Brahmbhatt

Jatin Ramesh Chunawala

The present invention provides a method for the preparation of multi-nutrient potassic fertilizer, by recovering potassium from sugarcane molasses based alcohol distillery effluent (commonly known as 'spent wash'). The process involves pre-treatment of spent wash to clarify the aqueous phase and utilization of the treated spent wash in production of potassic fertilizer. The present invention enables utilisation of spent wash for recovery of value-added product (viz., potash fertiliser of &#x3e;99% purity) and improves ease of 'Zero Liquid Discharge' compliance by subjecting the relatively benign process effluent to industrially practiced techniques for water recovery and salt reclamation.

Process for the preparation of potassic fertiliser from alcohol distillery effluent (spent wash)

Molasses based alcohol distilleries generate highly contaminated, dark coloured and foul smelling effluent (bio-methanated spent wash, BMSW, also known as post methanated effluent). While the prevailing practices for treatment of alcohol distillery effluents operate on the premises of 'liability management', high potassium content of spent wash (ca. 2% w/v in BMSW) offers an opportunity for its utilisation in production of potash fertilizers&#x2014;a major agricultural input. The present invention provides process for potash recovery from BMSW with concomitant environmental remediation of effluent. The process involves pre-treatment of BMSW followed by potash recovery through selective precipitation technique to produce potash fertilizers and activated carbon while generating a relatively benign effluent (&#x3e;80% remediation). It may further be possible for the alcohol distilleries to achieve ZLD status by incorporating commercially practiced water recovery techniques (viz., multiple effect evaporation/nano-filtration/reverse osmosis etc.) for downstream processing of the process effluent.

Process for potash recovery from biomethanated spent wash with concomitant environmental remediation of effluent

Although U.S. Pat. No. 8,182,784 teaches the recovery of potassium chloride from schoenite end liquor (SEL) using dipicrylamine as extractant, and consequently simplifies the recovery of sulphate of potash (SOP) from kainite mixed salt employing the scheme disclosed in U.S. Pat. No. 7,041,268, the hazards associated with this extractant have thwarted practical utilization of the invention. Many other extractants for potash recovery have been disclosed in the prior art but none has been found suitable so far for practical exploitation. It is disclosed herein that the bitartrate ion, and particularly L-bitartrate, precipitates out potassium bitartrate very efficiently from SEL with ca. 90% utilization of the extractant. In contrast, recovery of potassium bi-tartrate from sea bittern directly is relatively much lower. It is further disclosed that this precipitate can be treated with magnesium hydroxide and magnesium chloride to throw out magnesium tartrate with ca. 90% recovery while yielding a nearly saturated solution of potassium chloride which can be utilized for the reaction with schoenite to obtain SOP. It is further demonstrated that the magnesium tartrate can be treated with an appropriate amount of aqueous HCl and added into a subsequent batch of SEL to throw out potassium bitartrate once again which demonstrates the recyclability of the extractant. The overall loss of tartrate over a cycle was ca. 20% but the dissolved tartrate remaining in the K-depleted SEL and KCl solutions can be precipitated out as calcium tartrate from which tartaric acid can be recovered by known methods, curtailing thereby the loss of tartaric acid per kg of KCl to &#x3c;5 g. It is also demonstrated that through a similar approach, seaweed sap containing ca. 4% KCl can be concentrated to 20-22% KCl, with excellent utilization efficiency of tartaric acid, and this solution can similarly be utilized for SOP preparation. Potassium salts bearing other anions such as sulphate, nitrate, phosphate and carbonate can also be prepared from the isolated potassium bitartrate.

Selective extraction of potassium chloride employing tartaric acid as safe, benign and recyclable extractant

The present invention provides an integrated process for the recovery of sulphate of potash (SOP) and ammonium sulphate fertilizers from kainite mixed salt dispensing with magnesium hydroxide production. The process comprises, among other steps, producing calcium chloride from calcium carbonate through addition of hydrochloric acid; the calcium chloride being used for desulphatation of schoenite end liquor (SEL) obtained as liquid stream during decomposition of kainite mixed salt with water to obtain solid schoenite; using the resultant gypsum and carbon dioxide together with ammonia for the production of ammonium sulphate liquor and solid calcium carbonate, the latter being recycled in the process; producing carnallite from desulphated SEL; decomposing the carnallite to recover carnallite decomposed product (CDP) which is further refined under ambient conditions to obtain pure potassium chloride (KCl) utilized in the preparation of SOP from the schoenite. Except for ammonium sulphate recovery in solid state, where required, all operations are carried out at ambient temperature.

Integrated process of production of potassium sulphate and ammonium sulfate from kainite mixed salt

The invention relates to an integrated process for the production of 5-hydroxymethyl furfural (HMF), KSO, levulinic acid and formic acid from &#x3ba;-carrageenan, the latter being obtained from freshseaweed biomass after expelling the juice. Mg(HSO)was used in HMF synthesis, with co-production of galactose. The aqueous stream after HMF extraction was treated with the seaweed juice which process facilitated recovery of KSOin pure form. The galactose may be utilised for synthesis of levulinic acid and formic acid before or after KSOrecovery or, alternatively, utilised for other purposes. Catalysts required in the synthetic reactions are generated in the process itself while the process energy required is met out of additional supplies of the seaweed biomass which is subjected to combustion/gasification.

Process for improved seaweed biomass conversion for fuel intermediates, agricultural nutrients and fresh water

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

A highly pure 3,5-dibromo-4-hydroxybenzonitrile (bromoxynil) has been prepared in high yield from 4-hydroxybenzonitrile using eco-friendly brominating reagent comprising of 2:1 mole ratio of bromide to bromate salts in aqueous acidic medium without any catalyst under ambient conditions with no work up procedure. The product 3,5-dibromo-4-hydroxybenzonitrile was obtained in 91-99% yield with melting point 189-191&#xb0; C. and more than 99% purity by gas chromatographic analysis without any purification.

Process for the eco-friendly preparation of 3, 5-dibromo-4-hydroxybenzonitrile

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

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Gujarat, India

Pratyush Maiti