INSPECTION OF COMMERCIAL FERTILIZERS 45 



Colloidal Phosphate with Mineral Colloids 



This product was first registered in Massachusetts in 1929 by the Natural 

 Products Corp., Ocala, Florida, under the name of "Florida Phosphate with 

 Colloidal Clay." Later in the same year the name was changed to "Colloidal 

 Phosphate." 



In 1930 it was registered as "Colloidal Phosphate" by the Colloidal Phos- 

 phate Sales Corp. of New England, located at 126 Newbury Street, Boston, 

 Massachusetts. During 1930 two hundred eighty-two tons were sold in the 

 state. 



In 1931 it was registered by the Mardal Corp., 370 Lexington Avenue, New 

 York City. No sales were recorded in Massachusetts during that year. 



The following description of the product appears on page 51, Control Bul- 

 letin 51, published in 1929 by the Massachusetts Agricultural Experiment 

 Station. This description is applicable to the present-day product, although 

 it is claimed by the present promoters. Colloidal Products of America, Inc., 

 Soil Builders, Inc. Branch, Orlando, Florida, that an attempt is now made to 

 standardize the material so that it will run uniform in composition. 



"This product is a low-analysis natural Florida phosphate known to the 

 industry as 'pond phosphate,' a by-product in mining Florida rock phosphate. 

 In the recovery of this Florida rock phosphate, water is used. The soft, finely 

 divided phosphate, with more or less clay and silt, is washed into ponds or 

 basins, the finer material separating more abundantly at points farthest from 

 the washer. When the water evaporates, the very finely divided deposit re- 

 mains, and this is the source of the product under discussion." 



The material is lower in phosphorus and higher in iron and aluminum than 

 the raw rock considered suitable for the manufacture of superphosphate. Its 

 use as a fertilizer is therefore restricted at present to direct application to the 

 soil. From a fertilizer standpoint it supplies only phosphorus — and that in 

 the tricalcium, iron, and aluminum phosphate forms which are not readily 

 available according to official methods of analysis. 



In 1930 a vegetation pot test was conducted at this institution on some 

 comparatively new phosphates, including Colloidal Phosphate. (Pages 54-63, 

 Control Bulletin 54, Massachusetts Agricultural Experiment Station.) Briefly 

 stated, there was but little difference between Colloidal Phosphate and finely 

 ground rock phosphate, either in the dry matter yield or in the phosphoric 

 acid recovered. In Series I where the minimum phosphoric acid ration was 

 used, neither of these phosphates showed any average gain in dry matter yield 

 over the no-phosphate pots. Based on phosphoric acid recovery, both of these 

 raw mineral phosphates showed phosphoric acid availability amounting to 

 about one-fourth that of superphosphate. 



A comparison of the product sold in Massachusetts in 1930 with the prod- 

 uct registered in 1937 is shown by the following analysis. 



11930 1937 



Percent Percent 



I Moisture 4.47 4.64 



Total phosphoric acid 21.61 2A4~ 



Available phosphoric acid in neutral citrate of ammonia solution . . .21 2.88 



Insoluble phosphoric acid in neutral citrate of ammonia solution . . 21.40 20.26 



Water soluble potash None None 



Total nitrogen .03 .10 



Total calcium oxide 25.34 24.23 



Magnesium oxide 1.34 .62 



Carbon dioxide 4.95 1.63 



Iron oxide (FezOs) \ 15.24 3.63 



Aluminum oxide (AljOs) / 14.75 



Soluble sulfates Trace Trace 



Chlorine Trace Trace 



Insoluble matter 22.18 17.41 



