BROMINE. (Fn., Brame ; GER., Brom.)—Symbol, Br. Combining weight, SO.
This element was discovered in the year 1826, by Balard, of Montpellier, in the mother-liquor of the water from the salt marshes of that place. It is, at ordinary temperatures, a deep brown red coloured liquid, possessing a powerfully pungent and irritating odour, similar to that of ehlorine, but more suffocating and offensive. Its aqueous solution bleaches like that of chlorine, but not so powerfully, and it bears a close resemblance to chlorine and iodine in many of its other properties. It is very volatile, speedily filling with deep red vapours any vessel in which it is placed. It is highly poisonous. At 15° (59° F.) its sp. gr. is 2.98 ; at 22° (— 4° F.) it solidifies, forming a hard, brittle, laminated mass, of a dark, leaden-grey colour, and semi-metallic lustre. It boils at about 63° (140° F.). It is sparingly soluble in water, more readily in alcohol, and abundantly in ether. With hydrogen, it unites to form hydro-bromic acid; and with bases, to produce the salts called " bromides." Bromine occurs in small quantities in sea-water, one litre containing about 0.061 grm. The mother-liquor of sea-water, and of the water of many saline springs, contains such quantities of it as t,o admit of its extraction from these sources with considerable profit. After the removal, by crystallization, of the greater portion of the salts of potash and soda, the bromine remains behind, chiefly as bromide of magnesium. A current of gaseous chlorine is passed through the unerystallizable liquor, by mixing it with peroxide of manganese and hydrochloric acid in stone ware retorts, and distilling the mixture. In this way, the bromine is liberated from the magnesium, the liquor becoming at the same time of a deep orange-colour. The bromine then distils over into the receiver in the form of a heavy, dark-red liquid, surmounted by an aqueous solution of bromine.
At Stassfurt, from the salt springs of which place by far the largest quantity of commercial bromine is obtained, the manufacture of this substance was cotumenced by Frank in 1865, when its price was very high. A year later the price of bromine was reduced to one-half, in 1867 to one-sixth, and during the three following years it still steadily declined. The production was at first 3000 lb.
per annum, from which it rose quickly to 15,000 lb., and has, since that time, increased con siderably. The modus operand% employed by Frank at the present time is as follows. The raw material is the mother-liquor which remains after renaoving, by crystallization, the chlorides and double ehlorides of potassium and magnesium from the solution of raw Stassfurt salt. This liquor contains from 0.08 to 0.15 per oent. of bromine ; the later salt deposits sometimes contain much larger quantities.
The apparatus used consists of a stoneware pan or retort, of a capacity of about 80 to 100 cub. ft., set in blickwork. It is heated inside by means of a perforated leaden steam-pipe, passing through the lid of the still and reaching to the bottom, so as to deliver numerous small jets of steam. The remainder of the apparatus is shown in Fig. 394. The delivery tube of the retort is connected with a condensing worm A, sur rounded by cold water ; the end of this worrn communicates, by means of a glass adapter B, with the middle neck of a Woulfe's bottle C, holding about 18 pints, and furnished with a safety funnel a, and a siphon b, for drawing off the bromine. The third neck of the bottle contains a bent tube c, leading to a stoneware jar D, which is filled with moist iron filings ; this tube terminates in a glass cylinder d, which prevents it from becoming stopped up by the formation of ferrous bromide. The joints are made with lutes of clay and oil, bound round with parchment. The still is charged with the mother-liquor, peroxide of manganese, and sulphuric or hydrochloric acid, hpmforl rgnirilv to the boil ing point, by passing stes.m through it. The vapours of bromine passing over are condensed in the worm, and are run into the Woulfe's bottle C, where two strata are formed, the lower consisting of pure liquid bromine, and the upper, of a solution of bromine in water. The uncondensed vapour contains a little bromine, which renders it very offensive ; this is entirely absorbed by the iron filings. The first portion of the distillate is toter lation must be stopped, and the retort recharged.