SMOKE AKD DUST ABATEMENT — COTTKELL. 683 



PROBLEMS OF THE PORTLAND-CEMENT INDUSTRY. 



The Portland-cement industry is another direction in which the 

 precipitation process has proved of very practical importance. The 

 hrst instaUation of this kind was made under the direction of Mr. 

 Walter A. Schmidt at the mill of the Riverside Portland Cement Co. 

 near Riverside, Cal. Threatened litigation with the owners of sur- 

 rounding orange groves on account of nuisance and damage to fruit 

 and trees from the dust clouds of lime and clay escaping from the 

 cement kilns was the incentive for the cement company undertaking 

 tlie work. The company had already spent upward of a million 

 dollars in purchases of surrounding land and other expenses con- 

 nected with the nuisance and damage question, l)ut without securing 

 })ermanent relief. Experimental work on electrical precipitation was 

 commenced there in the summer of 1911 ; and as this was almost the 

 first practical extension of the processes to temperatures of 400° 

 to 500° C, many new engineering features had to be worked out. 

 The details of the final plant seen in construction in figure 46 and 

 in its present complete form in figure 47 were worked up through the 

 series of preliminary experimental units of progressively increasing 

 size shown in figures 48 to 51. Had there been sufficient ground space 

 available near the base of the kiln stacks the precipitating units 

 might have been placed there and a more compact and far less expen- 

 sive installation secured; but as it was, the only available space 

 seemed that above the roof at the top of the old stacks. Further- 

 more, the cement company preferred to incur this additional expense 

 rather than suffer any delay or interruptions of its regular operations 

 while changes were being made in the flues or stacks themselves. 



Consequently a reinforced concrete platform 90 by 190 feet was 

 built 80 feet above the ground, strong enough to support the entire 

 electrical equipment upward of 1,200 tons of steel going into the 

 installation as a whole. The present plant consists of 10 rotary 

 kilns, each 8 feet in diameter by 100 feet in length, fired with crude 

 petroleum and furnishing a total volume of nearl}'' a million cubic 

 feet of gas per minute to be treated. Out of this the electrical equip- 

 ment now collects nearly a hundred tons of dust per day. Figures 

 52 and 53 show the difference in appearance of the plant before and 

 after making the electrical installation. In figure 49 can also be seen 

 the experimental treater shown in figure 48. Figure 54 shows part of 

 five days' catch of dust sacked and piled. 



The treaters are of somewhat the same general type as those used 

 at the Selby and Balaklala smelters, but larger, with wider electrode 

 spacing and many improvements over these in details and general 

 design. There are 20 of them in all, two to each kiln stack con- 

 nected to it on opposite sides through louvre dampers, such as seen in 



