The Consett Company have reached a production of 3,400 tons in four weeks, or 850 tons per week, and of 134 tons in one day from a single furnace.
From the United States we have authentic accounts of an average production of 1,120 tons per furnace per week having been attained, and that even this great output has lately been considerably exceeded there. Both as to consumption of fuel and wear and tear, per ton of iron produced, these enormous outputs are attended with economy.
In the case of the Consett furnace they were obtained although the heat of the blast was under 1,100 deg. Fahr., while heats of 1,500 deg. to 1,600 deg. are not uncommon at the present day in brick stoves, thanks to the application of the regenerating principle of ex-president Sir W. Siemens.
But an economy which promises to be of great importance is now sought in the recovery and useful application of those constituents of coal which, in the coking process, have hitherto been lost; or, as an alternative, in a similar recovery in those cases in which the coal is charged in a raw state into the blast furnace, as is the practice in Scotland and elsewhere. This recovery of the hydrocarbons and the nitrogen contained in the coal, and their collection as tar and ammoniacal liquors, and subsequent conversion into sulphate of ammonia as to the latter, and into the various light and heavy paraffin oils and the residual pitch as to the former, have now been carried on for a considerable time at two of the Gartsherrie furnaces; and they are already engaged in applying the necessary apparatus to eight more furnaces. In the coke oven the recovery of these by-products—if that name can be properly applied to substances which yield the most brilliant colors, the purest illuminants, and the flesh-forming constituents supplied by the vegetable world—would appear at first sight to be simpler; but it has presented its own peculiar difficulties; the chief of which was, or was believed to be, a deterioration in the quality of what has hitherto been the principal, but what may, perhaps, come to be regarded hereafter as the residual product, namely, the coke. But the more recent experience of Messrs. Pease, at Crook, appears not to justify this opinion. You will see on our table specimens of the coke produced in the Carves-Simon oven, yielding 75 to 77 per cent. of coke from the Pease’s West coal, which they have now had at work for several months. Twenty-five of these ovens are at work, and the average yield of ammoniacal liquor per ton of coal has been 30 gallons of a strength of 7 deg. Twaddell, valued at 1d. per gallon at the ovens; the quantity of tar per ton has been 7 gallons, valued at 3d. per gallon. These products would therefore realize 4s. 3d. per ton of coal. Of course the profit on the ton of coke is considerably more, and to this has to be added the value of the additional