M U R

m u rt

( ISO )

fuch as the preparation of fal ammoniac,' ofmuriatic acid, and of oxymuriatic acid for thebleacheries. In fituations however where theferefidues are not to be obtained, it mud beprepared by the direCt d'ecompofition of muriatedloda: the two cheapeft methods of effecting thisappear to be by means of gypfum and of ironpyrites.

The firft of thefe is carried on in the follow-ing manner. Take any quantity of calcinedgypfum and | of its weight of common fait;mix them accurately by grinding, or in anyother convenient way, then add to the powdera fufficient quantity of water and make it upinto balls three or four inches in diameter.When thefe balls are dry, let them be calcinedfor five or fix hours in a reverberatory furnace,then break them down into pieces no largerthan a liazle nut, and lixiviate them with coldor warm water: the liquor when boiled to apellicle affords by cooling cryftals of Glauber’sfait.

'The fecond method, or that by means ofpyrites is thus accompliihed. Take ioo lbs. ofcommon pyrites and reduce it to fine powder,then add 40 lbs. of common fait; mix the twoingredients well together and expofe the mafsfor 60hours to a roafting temperature; a copiousdifengagement of muriatic and fulphureous' acidswill take place, and the mafs will ftill continuepulverulent, but of a brownifh red colour,and reduced in weight to 107! lbs.

Being now lixiviated and the liquor boileddown to a proper confiftence, there will bedepofited about 45 lbs. of cryftallized fulphatof foda, and the mother water evaporated todrynefs will leave between 8 and 9 lbs. of afaline mafs confiding of fulphat of foda, muriatof iron, and a little undecompofed common fait.The infoluble refidue confifts of fulphuret ofiron with excefs of oxyd, weighing 67-1 lbs. ina highly favourable date for vitriolization.

A confiderably greater quantity however offait can be decompofed by a given weight ofpyrites if there be added to the mixture .eithercharcoal, pitcoal, or peat, but efpecially thelatter. For this purpofe 100 Tbs. of pulverizedpyrites and 3C0 lbs. of dried peat being wellmixed together, 65 lbs. of fait diflblved inwater are to be added, and the whole mafsafter being carefully tempered is to he made upinto balls. Thefe balls when dry are to beplaced in a reverberatory furnace with a littlefuel jud to kindle them, after which they willburn of themielves; the combudion is to be1 Pelletier Mew. de Chem. If.

kept up as gentle as poflible til! the incinerationis compleat, and then the allies being lixiviatedand the liquor boiled down in the ufual manner,there will be procured 70 lbs. of crydallizedfulphat of foda, and 17 lbs. of dry fait, confid-ing of muriat of iron and fulphat of foda, fromevaporating the mother water.

The fulphat of foda whether obtained fromthe fources above pointed out or from any other,may be decompofed fo as to afford its alkali ina feparate date by either of the two followingmethods, the fuccefs of which has been provedby experiments on a very large feale.

1, Decompcfition of Glauber’s fait by the combinedaElion of chalk and charcoal.

Take 1000 lbs. of calcined Glauber’s fait and550 lbs. of charcoal, and mix the two ingredients'accurately together by grinding; when the mix-ture appears compleat add by degrees 1000lbs. ofwafhed chalk, and continue the grinding tillthis alfo is mixed with the other materials.Now let a reverberatory furnace be lighted,and as foon as it is red hot let it be chargedwith 4.or 500 lbs. (more or lefs according to-the fize of the furnace) of the above mixture,and clofe the door. During the firft part ofthe procefs, while the materials are yet pulveru-lent the flame muft be kept as gentle as poflible-left it fhould carry part of the powder up thechimney; but as foon as the matter begins toclot the flame may be increafed. At this timethe mafs muft be carefully worked about withan iron rake in order to expofe frelh furlaces tothe aCtion of the flame. When the whole hasacquired a pafty confiftence jets of inflamedfulphuretted hydrogen will be perceived to ifl'uefrom every part, accompanied by a moderatebut very perceptible exploilon and effervefcence;and during the whole of this ftage of theprocefs the rake muft be ufed very vigorouilyin order to expedite the difengagement of thegas. When the jets of flame ceafe, and thematter becomes nearly fluid the rake may hewithdrawn, and a bar of cold iron is to beintroduced from time to time in order to judgeof the progrefs of the operation by the famplethat adheres to the end of it: if this cracks asit grows cold and prefents an uniform granulartexture the heat has been continued long enough,and the matter muft then be fpeqdily withdrawnleft it fhould be fritted by the further action ofthe fire. The flame being accordingly turnedofF for a few minutes, the mafs returns to apafty • confiftence and is withdrawn from thefurnace by means of the rake. As foon as itp. 308, or An de Chem. six.