| Show r SULPHUR DIOXIDE effect of its presence in smelter smoke on men and vegetation the U S geological survey in a report on sulphur dioxide in smelter nelter Si smoke discusses its effect upon men and vegetation as follows some authorities hold that sulphur dioxide is distinctly harin harmful ful others that although its effect is highly disagreeable and of course not beneficial the harm done by it is not serious it is always present in readily noticeable quantities in the air about copper smelting smelling sm elting and roasting furnaces in fact to such an extent that the ordinary visitor to these plants finds the atmosphere practically unbearable furnace men however work in this atmosphere continuously and do not seem to suffer permanent harm from their contact with the gas on the other hand the effect of the gas on vegetation is seriously harmful A summary of the action of sulphur dioxide on plants may be stated as follows the action shows itself by spots on the leaves the whole leaf sometimes becoming seared and yellow this drying of leaves and twigs and the falling behind in yearly 6 growth give the general appear appearance anc e of a dying plant the severity of the symptoms varies with the proportion of sulphur dioxide in the atmosphere the sulphur dioxide ide causes a derangement of the water circulation cu leading to loss of water thus causing the drying of the leaves the gas is absorbed by the leaf surface as a a whole probably acting on the chlorophyll in the leaf sulphates eventually being formed there is no direct action either by sulphur dioxide or sulphur trioxide on cm the roots of plants and hence no indirect action through gh the soil it is generally conceded that the soil is not injured by sulphur dioxide or sulphur trioxide either acting directly or dissolved in the rain the action of sulphur dioxide on the life of the plant is intensified fied fled by light and high temperature and by moisture in the air plants in damp climates or climates in which fogs occur occar are much more subject to damage than those in dry climates this statement is somewhat in dispute but from the writers own experience he is inclined to believe that the damage is greater in the presence of moisture than when moisture is practically absent the first thought of course that comes to the engineer is to transform this now useless substance into some valuable byproduct such as the sulphuric acid or sulphur mentioned above the solution of the problem along these lines is so by local conditions that no general statements can safely be made in the south there is a considerable demand for cheap sulphuric acid in connection with the treatment of phosphate rock in the manufacture nd for the kurpa purpose e of of fertilizer ferilli or and also byproduct product of col coking converting the ammonia by ovens into ammonium sulphate sulp liate this demand made it possible in a large measure to solve tile the smoke problem in the vicinity of ducktown Duck Duch town and copperill Copper hll lill tenn NV where here two smelting smelling sm elting plants manufacture sulphuric acid from the sulphur dioxide in smelter smoke the smelters shelters sm elters of the west are not favorably situated in this respect at least at present as the market for sulphuric acid is comparatively small in utah however there are large phosphate deposits which no doubt will be utilized in time so that a great demand for cheap acid may develop As already stated the is always local at anaconda the au question estion of treating the tailings or product from the concentration mills for the recovery of their copper content is now beh being 19 seriously considered the process that will be applied is one of roasting the tailings and leaching the roasted product with sulphuric c acid this sulphuric acid will probably be manufactured locally from the gases of the mcdougal furnaces that roast the concentrate of the mills although all of the sulphur dioxide produced at cannot be utilized the removal of a part p rt of it from the smoke stream will have a generally desirable effect the hall and the processes now prominent in the amelioration of the smoke difficulty are designed to remove sulphur from the smoke stream in the form of elemental sulphur the hall process eliminates the sulphur in the ores direct in the form of elemental sulphur and prevents the formation of sulphur dioxide in the smoke stream with the production of elemental sulphur the leading idea here also is the winning of a valuable by prod act which will yield a profit or at least meet the expense of the applied process elemental sulphur at present has a ready market but it is easy to show that the possible production of sulphur by these means will glut the market the problem is again a local one if the sulphur dioxide in smelter smoke cannot be converted into valuable by prod proa acts the problem becomes one of finding a cheap means to destroy the sulphur dioxide and convert it into a harmless substance from this standpoint although for obvious reasons the sulphur dioxide may not be converted into sulphuric acid I 1 it might still be converted into elemental sulphur which could be stored in isolated places at various times many suggestions have been made for the destruction or removal of sulphur dioxide such as its removal by solution in water or its absorption by limewater with the formation of lime sulphite all of which except under certain local conditions when they may become applicable in the end give rise to just as great a nuisance as does the original substance at present the best known metai bd for minimizing the nuisance of sulphur r dioxide in smelter smoke is to dilute the smoke and diffuse the dioxide to such ar an extent that it will be practically harr harmless F |
