At the recent meeting of the Iron and Steel Institute, London, the president-elect (Mr. Bernard Samuelson, M.P.), delivered the following inaugural address:
He showed that the world's production of pig iron has increased in round numbers from 10,500,000 tons in 1869 to 20,500,000 tons in 1882. The blast furnaces of 1869 produced on the average a little over 180 tons per week, with a temperature of blast scarcely exceeding 800° Fahr. The consumption of coke per ton of iron varied from 25 to 30 cwt. To-day our blast furnaces produce on the average upward of 300 tons per week.
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° Fahr., while heats of 1,500° to 1,600° 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° 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 weight of coke, which in the ordinary beehive ovens from coal of the same quality is only 60 per cent. or in beehive ovens having bottom flues about 66 per cent., while in the Carves ovens it is, as I have said, upward of 75 per cent. Against these figures there is a charge of 1s. 4d. per ton of coke for additional labor, including all the labor in collecting the by-products; the interest on the first cost of the plant, which is considerable, and probably some outlay for repairs in excess of that in the case of ordinary ovens, has also to be charged.
Mr. Jameson takes credit for the combustible gas, which is used up in the Carves ovens, but which remains over in his process, and is available, though not nearly all consumed, in raising steam for the various purposes of a colliery, including, no doubt, before long, the generation of electricity for its illumination. It is right to state that prior to 1879 Mr. Henry Aitken had applied bottom flues for taking off the oil and ammoniacal water to beehive ovens at the Almond Ironworks, near Falkirk. He states that the largest quantity of oil obtained was eleven gallons, the specific gravity varying from 0.925 to 1.000, and that the water contained a quantity of ammonia fully equal to 5½ lb. of sulphate of ammonia to the ton of coal coked. The residual permanent or non-condensed gases were allowed to issue from the end of the condenser pipe, and were burnt for light in the engine-houses, but it was intended to force them into the oven again above the level of the coke. Owing to the works being closed, nothing has been done with these ovens for some years.
I may mention, by the way, that it is proposed to apply the principle of Mr. Jameson's process to the recovery of oil and ammonia from the smouldering waste heaps at the pit-bank, by the introduction into these of conduits resembling those which he applies to the bottom of the beehive oven. There is every reason to expect that one or more of these various methods of utilizing valuable products which are at present lost will be carried to perfection, and will tend to cheapen the cost at which iron can be produced, and still further to increase its consumption for all the multifarious purposes to which it is applied.