POT AMI UM 

 NITRATE 



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MANUFACTURE 



In a factory ex Murwanpur, four 1 1 ales from Cawnpore, the folio wing 



was the process of manufacture : " The earth is stacked 



if liiters (kuria or kothi). 1 feet long. 9 feet broad, and 1 foot dam. They 

 are placed end to end with un earthen yAora or jar (nantt). 1| feet in oiaii 



linried in the ut-oiiml between th. n,. 1 1,,- i , lt fa o { puddled 



<-la\ , mid IH so arranged that i i<, i towards the central longi- 



tndinal line of the filter. This central hn.- has a elope towards the outlet con- 

 nrctnii.: with tho jar. On tho floor is la work of n 



i w hieh rest on 1 1, I the cross- pieces of -p of 



the *ide pieces. The lilt. ,!| v packed w,t nn d water 



then poured on tho surface, whi.-h commences to tn> kl>- out m on.- 

 as niti.ii- i-nnr. After the first charge of water, more is point*! <rface 



until the I. i-in.- trickling out appears to be too weak to work. Tho exhausted 

 .-<>il n .1 i the lilter-, is then taken out and thrown on a heap, which get* Urge by 

 the time the season ends. The liquid from the nmtd is baled out and transferred 

 t" <m iron ,ng pan or buiiur (karahi). which in supported on a 



phut". The boiler is C feet in diameter und 

 together, and costs about Rs. 20 ; the liquor is boiled t 

 until it is HiilHciently concentrated. To detfrnun 



taken and placed on the thumb-nail. I iug is 



considered to be complete. 



" The hot boiled liquid is transferred to open vessels of rough pottery to cool 

 and crystallise. The crystals will usually hu\o KiinViontly formed to be collected 

 next inorniiiL'. They are taken out and drained in basket* which act as filters, 

 and then thrown into a pit in the ground, where the crude saltpetre, or kachcha 

 shora us it is called, is stored " (Hooper, I.e. 26-7). 



Saltpetre thus obtained (by artificial heat) is termed /aria shora. The method 

 of making crude saltpetre by the heat of the sun is practised in the drier parU 

 of the Panjab and in other provinces whore t he climate permits, but tho saltpetre 

 (obi shora) is not considered of such good quality. A large quantity of obi thora 

 is made annually at Hansi in the Hissur 



" The quality of crude saltpetre is considerably influenced by the quality of 

 the nitrous earth from which it is made and the processes adopted for its manu- 

 facture." Analyses of various samples of crude saltpetre are given by Hooper 

 (I.e. 31-2). The amount of potassium nitrate ranges from nearly 80 per cent. TWd. 

 in a sample from Hamerpur, to as low as 26*8 per cent, in a sample from Okara, 

 and an average of 53 might be given. 



Impurities. The chief impurity is common salt. Ordinary samples of Impurities, 

 crude nitre are stated to contain from 40 to 64 per cent, nitrate of potash, Common sit. 

 and to be worth, at manufactories within easy distance of railways i; ; the 

 north of India, one anna per unit per maund for the percentage of potassium 

 nitrate present. According to Hooper, a sample containing 40 per < 

 nitrate of potash would thus be worth Rs. 2-8 per maund, and samples Prfos. 

 containing 64 per cent, of nitre, Rs. 4 per maund. Samples with less than 

 40 per cent, nitre would be valued at less, and those containing over 

 64 per cent, nitre at more than one anna per unit. 



Refining. Before the nitre is ready for market, it has to be freed from Refineries. 

 impurities. This is done in refineries, of which there were 399 at work in 

 Northern India (Panjab, North-West Frontier Provinces, United Provinces, 

 Bihar) in 1904-5 ; 281 of these were in Bihar (Rec. Geol. Sun-. Ind., 

 1906, xxxiii., 19). Hooper gives a full account of the arrangements in a 

 refinery at Jaimow, Cawnpore, in the United Provinces, to which tin- 

 reader is referred for details. With regard to the methods followed, he 

 says, " The process varies in different refineries and in different parts of 

 the country. But as chloride of sodium is the principal impurity and as 

 its solubility is practically constant, all the processes followed are based 

 on the varying solubility of nitrate of potassium in hot and cold solutions." 



The method pursued, according to Hooper, is essentially as follows: In 

 starting tho refining process, nitre earth, obtained from the factory soil, is filtered 

 and the crude nitre solution obtained boiled down, clarified by sedimentation 



973 



Location. 



