Journal . e mixture, obtained in either way,treated with carbonic acid. This treatment resolvesitself into two stages— the purifying and the car-bonating process. In the lirst instance, ihe carbonicacid acts first on the crude liquora by precipitatingalumina, iron, and silica. The solution is then filtered,and the clear liquor subjected to the further action of acurrent of carbonic acid gas, when pure sodium bicar-bonate is precipitated. At this second stage, the sul-phides and cyanides present are also decomposed, withthe evolution of sulphuretted hydrogen and washing, the
Journal . e mixture, obtained in either way,treated with carbonic acid. This treatment resolvesitself into two stages— the purifying and the car-bonating process. In the lirst instance, ihe carbonicacid acts first on the crude liquora by precipitatingalumina, iron, and silica. The solution is then filtered,and the clear liquor subjected to the further action of acurrent of carbonic acid gas, when pure sodium bicar-bonate is precipitated. At this second stage, the sul-phides and cyanides present are also decomposed, withthe evolution of sulphuretted hydrogen and washing, the bicarbonate is nearly chemicallypure, and is either by diving converted into marketablesodium bicarbonate, or by calcining into pure monocar-bonate. The liquor remaining consists mainly of Bodiumchloride, and can be used over and over again forlixiviating fresh black a-h. To make pure bicarbonatefrom crude sodium bicarbonate (from the ammonia-sodaprocess), the latter is dissolved in a solution of sodium. directed into the furnace through the tuyeres I!, bywhich the mixture is reduced to the molten state, thesulphur being set free and carried upwards, togetherwith sonic sulphurous acid formed, while the silica, com-bining with the iron, forms a slag, which is run off fromlime to time. In the upper part of the furnace, whichis closed with a hopper-charging arrangement, or intothe brick-lined tubes C and D, a blast of hot or cold ait-is directed, in order to completely burn the sulphur,which rises in a finely-divided state from the heatedmaterials below. In connection with the pipe 11, is awater lute E. which serves as a safety valve in the eventof excessive pressure of the gas.—S. H. Improvements in tl,. Manufacture of Bicarbonate of Soda,i,i,/ Soda-Ash. N. Mathieson and .1. Hawliczek,Widnes. Eng. Pat -2-J7, -Ian. 6, 1886. invention has for its object the manufacture ofeither pure bicarbonate or of pure nionocaibonate of sodadirect from the crude vat-liquor, or red
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Keywords: ., bookcentury1800, bookdecade1880, booksubjectchemist, bookyear1882
