How Rock Phosphate Is 

 Prepared For Illinois Farms 



HAT farmers in Illinois are 

 ^* /^ probably the largest users of 

 S^ rock phosphate in the middle 

 ■west is borne out by the contacts recently 

 made by John R. Spencer with producers 

 in the area of Middle Tennessee. While 

 they have used from over 10 to 35 thou- 

 sand tons per year, not many are familiar 

 with the way phosphate is mined and pre- 

 pared for farm use. 



Phosphate comes in a rock form, 

 largely of two types — a brown, high 

 analysis rock and a blue rock, the latter 

 usually of a lower ^ade. 



The middle Tennessee area, while im- 

 portant from Illinois farmers' standpoint 

 because of its relative nearness, has one 

 of the smaller deposits of the United 

 States. Florida, Idaho, Montana, Utah 

 and Wyoming contain much larger de- 

 posits. There are smaller deposits of 

 phosphate rock also in Kentucky, South 

 Carolina, and Arkansas. 



In world production of phosphate 

 rock, the United States is exceeded only 

 by Africa, and followed by Europe, with 

 the Island deposits, and Asia. A fact 

 however, of particular interest to our 

 State, is that the Tennessee brown rock 

 phosphate deposits may be exhaustCil 

 within the next half-century. 



Phosphorus a Necessity- 

 It is fairly.wcll known that phosphorus 

 is a necessity m animal, human and plant 

 nutrition. It has been shown that a large 

 proportion of the soil types of the United 

 States are deficient in phosphorous, caus- 

 ing low yields and low quality of crops 

 and pastures. 



It is well recognized that certain ele- 

 ments are essential to plant life, among 

 which phosphorous is of major impor- 

 tance. Plants neither ^mature properly, 

 nor produce healthy well developed seeds 

 unless they are supplied with sufficient 

 quantities of phosphate. Not only do 

 greater yields result from the addition ot 

 phosphate to phosphorous deficient land 

 but the quality of the crop is improved. 

 However, not all land in Illinois is lack- 

 ing in phosphorous. 



In the Tennessee area, phosphate rock 

 is mined both bv the timehonorcd hand 

 and horse method, and by the modern 

 dragline and steam shovel method The 

 overburden is usually relatively light, al- 

 though there is quite a range from 1 or 

 two feet, to n or 16^ feet depth. This 

 raw material then starts through a scries 

 of purification processes following tlie 

 mining. Tlie method as now described is 

 the. process through which a large part of 



20 



the Tennessee rock phosphate goes. 



First the rock and finer material and 

 water, is mixed mechanically in a "Pug- 

 Mill". It is then reduced in size by pri- 

 mary crushing operations, and then goes 

 through washing cylinders. The purpose 

 of washing is to remove as much clay and 

 other impurities as possible. The lighter 

 clay and other material rises to the top, 

 and the heavier phosphate material settles 

 to the bottom. 



From the washing cylinders, the larger 

 phosphate rock lumps proceed toward the 

 final process. The finer material now 

 moves with water through a series of set- 

 tling Jevices, the purpose of which is to 

 remove all possible impurities. The rock 

 and finer material arc now in wet stor- 



age, and proceed from there through 

 driers and dry storage. 



Tlie next step is crushing and grinding 

 which reduces the phosphate material to 

 a high degree of fineness. Fineness of 

 grinding is an important consideration 

 in the farm use of rock phosphate. After 

 grinding, the material is ready for car- 

 load bulk shipments, or bagging for rail 

 and truck shipments, a large part of 

 which moves into Illinois. 



The raw rock phosphate as' it is called 

 to differentiate it from acid phosphate, 

 will contain from 12 to 15^^ of true 

 phosphorous, or from 30 to 35% phos- 

 phorous acid, or from 60 to 75% bone 

 phosphate of lime. TTie three methods 

 of reporting phosphorous contents are 

 sometimes confusing to the farmer, and 

 in the main, the two methods most com- 

 monly employed are the True Phosphor- 

 ous, or (P) content, or Phosphorous Acid 

 (P205). If one wishes to report it as 

 Bone Phosphate of Lime (BPL) the true 

 phosphate is multijilied by 5. 



• \ 



WHERE ROCK PHOSPHATE IS WASHED AND GROUND 



Fertilizer Bound ior Illinois Farms is Prepared for Shipment in T^ese 

 Tennessee Plants. 



I. A. A. RECORD 



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