The Phosphates of America. 79- 



and furnace is arranged with three conduits, one for the smoke 

 and heat, one for the buckets of the elevator, and one for the dry- 

 air draught. The partition between the smoke and combustion 

 flues and that of the elevator is thin iron after reaching the height 

 of the brick- work. The buckets are constructed of screen wire, so 

 that the escape of vapor from the heated rock is impeded as little 

 as possible. The partition between the bucket-flue and the dry- 

 air flue is perforated at intervals, so that the draught of dry air 

 will produce the effect of drawing off the vapor from the buckets 

 of heated rock as they pass upward through the elevator-flue. The 

 movement of the elevator is so slow that about twenty minutes 

 from the starting at the bottom, or boot end, are required to de- 

 liver a bucket of phosphate-rock at the top ; after the delivery is 

 once commenced, however, it is continuous. At the top, the chain 

 of buckets passes through a third, or drying-screen, which revolves 

 in a square, heated chamber, shown in the illustration at the top of 

 the dryer-frame. In passing through this dry screen, all the sand 

 or material that is not rinsed or washed out of the interstices and 

 from the clay deposit of the rock, is knocked off in a separate par- 

 tition of the hopper underneath the heated chamber. The phos- 

 phate-rock is delivered, as shown in space broken away, to the 

 hopper just underneath the open end of the screen at the rear of 

 the dryer, and is delivered, it will be observed, in chutes from this 

 altitude to the storage-bins in the warehouse, or on board cars at a 

 railroad track, the buckets cojitinuing their course down the in- 

 clined flue to the boot, to receive the continuous flow of phosphate. 

 There is a draught of hot, dry air thrown up this return flue, that 

 meets the phosphate being delivered from the dry screen, and 

 carries off what remaining vapor there may be arising from the 

 heated rock through an opening into the stack above. 



The operation of this system of machinery is automatic after 

 leaving the crusher, and every motion of the rock is in the direc- 

 tion required to reach storage or shipment. The water supply at 

 different mines, requiring different arrangements of pumping ma- 

 chinery, the latter has not been included in our drawing. 



From the dry-screen, running back to the waste or culm pile, 

 there is a conveyor which relieves the dry-screen of the sand and 

 material that would otherwise accumulate beneath it. Where the 

 phosphate is found in a clay matrix, it is not practicable to use a 

 dry screen successfully; the latter is therefore in such cases elimi- 

 nated, and a pug introduced in place of it, similar to the machine 



