Phosphate rock

“ Phosphatization sometimes takes place, amorphous phosphate of lime being substituted for carbonate of lime, and these replacement products often have great value as sources of natural fertilizers. On ocean rocks in dry climates the droppings of birds (guano) which contain much phosphate, percolating into the underlying limestones change them into a hard white or yellow phosphate rock (e.g. Sombrero, Christmas Island, &c.) , sometimes known as rock-guano or mineral guano. In the north of France beds of phosphate are found in the chalk; they occur also in England on a smaller scale. ”

“ Phosphorite, when occurring in large deposits, is a mineral of much economic value for conversion into the super phosphate largely used as a fertilizing agent. Many of the impure substances thus utilized are not strictly phosphorite, but pass under such names as “rock-phosphate,” or, when nodular, as “coprolite” (q.v.) , even if not of true coprolitic origin. The ultimate source of these mineral phosphates may be referred in most cases to the apatite widely distributed in crystalline rocks. ”

“ If your garden soil is deficient in phosphorus, adding rock phosphate to the compost pile may accelerate its availability in the garden, far more effectively than adding phosphate to soil. If the vegetation in your vicinity comes from soils similarly deficient in phosphorus, adding phosphate rock will support a healthier decomposition ecology and improve the quality of your compost. Five to ten pounds of rock phosphate added to a cubic yard of uncomposted organic matter is about the right amount. ”

“ Phosphate is another king whose sway within his narrow domain is as absolute as is that of cotton. The United States furnishes more than half the phosphate rock of the world, and of this the South supplies all but an inconsiderable quantity. This product, of vast consequences to the agriculture of this section, is a comparatively recent discovery. The active development of phosphate mining commenced in South Carolina in 1868 ”

“ Common salt applied to a soil modifies its power of attracting and holding water.
11. Phosphorus never occurs in nature in a free state but exists in combination in greater or less quantities in all soils. Its combinations are also found in large deposits of minerals known as phosphorite and apatite and as so-called pebble deposit and phosphate rock. Phosphorus in some sort of combination is one of the most essential elements in animal and plant food. In animals its compounds form almost all of the mineral matter of the bones, and in plants they are the chief constituents of the ash of seeds. ”

“ That the people of Europe have made some use of the science thus evolved is evident from the simple fact that they are taking out of the United States every year about a million tons of our best phosphate rock for which they pay us at the point of shipment about five millions dollars; whereas, if this same phosphate were applied to our own soils that already suffer for want of phosphorus, it would make possible the production of nearly a billion dollars' worth of corn above what these soils can ever produce without the addition of phosphorus. ”

“ In the yield of gypsum, phosphate rock and salt the United States leads the world. In sulphur it is a close second to Sicily. Phosphate rock is heavily exported, and in the opinion of the National Conservation Commission of 1908 the supply cannot long satisfy the increasing demand for export, which constitutes a waste of a precious natural resource. Other minerals whose production may be found stated in detail in the annual volume on Mineral Resources of the United States Geological Survey are: natural pigments, felspar, white mica, graphite, fluorspar, arsenic, quartz, barytes, bromine. ”

“ This is prepared on a commercial scale by heating phosphate rock (which contains calcium phosphate) with sand and coke in an electric furnace. Phosphorus occurs in two forms, white and red. White phosphorus, which is formed when the vapor of the [Pg 287] substance is quickly cooled, is, in the pure state, almost colorless, melts at 44° C., boils at 287° C., is readily soluble in various solvents, and is luminous in the air, at the same time emitting fumes (the oxidation product, phosphorus pentoxide) . On gentle warming in the air, it takes fire and burns with a brightly luminous flame. ”

“ There are prodigious layers of these bones lying at a great depth in the rock, where there is no cavern to suggest that the animals entered by it, or that they were taken there by man. The beds of phosphate which English enterprise has turned to so good an account in this part of France, and which are followed in the earth just like a seam of coal or a vein of metal, are merely layers of bones. While I was at Brengues, the skeleton of a young rhinoceros was discovered in the phosphate mine at Cajarc. ”

“ The first mode of occurrence is of little significance practically, for the crystalline rocks generally contain too little phosphate to be valuable, though occasionally an igneous rock may contain enough apatite to form an inferior fertilizing agent, e.g. the trachyte of Cabo de Gata in south-east Spain, which contains 12–15% of phosphoric acid. In many deposits of iron ores found in connexion with igneous or metamorphic rocks small quantities of phosphate occur. ”

“ The amount of oxide of iron and alumina in raw phosphates is of great importance, as phosphates containing these bodies are liable to cause superphosphate to “go back” or form what is called “reverted” phosphate, the percentage of “soluble phosphate” being reduced thereby. For this reason many of the older supplies have been replaced by newer and better ones. Florida rock phosphate of high grade contains 75 to 78% of phosphate of lime, and Florida land pebble phosphate about 70%. ”

“ Michigan is the largest producer, followed by Kansas, Iowa, New York, and Ohio.
Phosphate Rock. The United States is the world's largest producer of phosphate rock. The production of this mineral began in South Carolina in 1867, and reached a maximum output there of 541,645 long tons in 1889, having decreased to 321,181 long tons in 1901. Its production in Florida began in 1888, and has increased almost steadily to 751,996 long tons in 1901. Tennessee, the only other State producing large quantities, began to yield in 1894, and in 1901 it produced 409,653 long tons. ”

“ Animal Bone.—The original source of phosphoric acid as a fertilizer was animal bone, just as hard-wood, unleached ashes were the source of potash. The organic character of the animal bone made it appear more truly a manure than could any rock or other inorganic substance. There is no more satisfactory source of phosphoric acid than animal bone, and if it were in full supply for the needs of soils, there would be little occasion to discuss the merits of rock-phosphate and other similar materials. ”

“ Rock-phosphate, known as floats, is not a profitable source of plant-food for soils deficient in organic matter, when compared with acid phosphate. It is more nearly profitable in an acid soil than in one that has no lime deficiency. It gives more satisfactory results when mixed intimately with stable manure than when used upon land that remains deficient in organic matter. Applications should be in large amount per acre—500 to 1000 pounds—in order that the amount of readily available phosphoric acid may meet the immediate need of plants. ”

“ The practical and commercial side of phosphate mining occupies almost the whole of this volume, although it is supplemented by some notes on the geology of phosphate deposits and numerous tables of chemical analyses. The raising of phosphates from the beds of streams, the mining of pebble-deposits and of rock phosphates are described briefly, and copious information is given in regard to transportation, freights, prices, cost of production, companies engaged in the business, and similar matters connected with the industry. ”

“ The use of ground rock-phosphate in stables is coming into use in some localities, chiefly through the recommendation that it be mixed with manure to secure availability of its own plant-food. It is not a preservative except in so far as it acts physically as an absorbent. It should not displace acid phosphate in stables, the preservation of nitrogen in the manure being the vital matter. ”

“ Not to speak of, but some of our farmers are beginning to use the raw phosphate. Our experiment station has found that our most extensive soil types are not rich in phosphorus, and has republished for our benefit the reports from the Maryland and Ohio experiment stations showing that the fine-ground natural rock phosphate appears to be the most economical form to be used and that it is likely to prove much more profitable in the long run, although it may not give very marked results the first year or two. May I ask what products you sell from your farm, Mr. ”

“ If a sample of copper contained 0.5 per cent. of arsenic, and 1 gram of it were taken for an assay, how much standard uranium acetate solution would be required in the titration?
PHOSPHORUS AND PHOSPHATES.
Phosphorus rarely occurs among minerals except in its highest oxidized state, phosphoric oxide (P2O5) , in which it occurs abundantly as "rock phosphate," a variety of apatite which is mainly phosphate of lime. Phosphates of most of the metallic oxides are found. Phosphoric oxide in small quantities is widely diffused, and is a constituent of most rocks. ”

“ While the phosphoric acid of apatite is highly desirable for use in fertilizers, the crystals do not occur in sufficient abundance to make them commercially available, and non-crystalline phosphate rocks are resorted to for this purpose. ”

“ Dependence should be placed upon the readily available acid phosphate in all instances until experiment on the farm shows that the rock-phosphate is a cheaper source of plant-food than the acid phosphate. ”

“ It can be used with profit in any of these forms, but the data thus far secured in comparative experiments plainly indicate that, with equal amounts of money invested, the natural rock phosphate will give the greatest profit in rational permanent systems. ”

“ In addition to these crystallized varieties, there are massive varieties, fibrous, concretionary, stalactitic, or earthy in form, which are included together under the name phosphorite (q.v.) , and it is these massive varieties, together with various rock-phosphates (phosphatic nodules, coprolites, guano, &c.) which are of such great economic importance: crystallized apatite is mined for phosphates only in Norway and Canada. ”

“ So much for the metals in soils; but, important as they are, plants can not live on them alone. Among the nonmetallic bodies phosphorus stands high among essentials, and for it we are indebted to the sea and the interior of the earth. Many living creatures extract phosphorus from the sea water—combine it chiefly with lime, and use the phosphate for making skeletons or shells, as the case may be. ”

“ The soils formed by disintegration of these rocks probably all have some phosphorus in them; but where there is vigorous plant growth, it soon tends to become exhausted, and must be renewed. For this reason the use of phosphates has become of prime importance in Agriculture. The possession of beds of rock carrying phosphorus has come to be of international importance. ”

“ Under the heading of manures that are used purely for their phosphatic benefit to the soil are superphosphate and basic slag.
Superphosphate.—This is the typical phosphatic manure, and is the base of the numerous artificial manures used on the farm. Superphosphate is made by dissolving raw phosphatic minerals in sulphuric acid (oil of vitriol) , the tribasic phosphate of lime which these contain being converted into the so-called “soluble phosphate,” sulphate of lime being formed at the same time. ”

“ An artificial phosphate is thus prepared: Melt in an oven a mixture of 100 parts of phosphorite, ground coarsely, 70 parts of acid sulphate of soda; 20 parts of carbonate of lime; 22 parts of sand, and 607 parts of charcoal. Run the molten matter into a receiver filled with water; on cooling it will become granular. Rake out the granular mass from the water, and after drying, grind to a fine powder. The phosphate can be kept for a long time without losing its quality, for it is neither caustic nor hygroscopic. ”

“ The hard part of bone is about nine-tenths phosphate, and phosphorus is an element of molecules organized into muscle and nerve.
The proportion of phosphates in the crust of the earth below organic remains is very slight, insufficient for the support of the higher forms of vegetable or animal life. It has been concentrated and gathered into the soil by the selective agency of the organic world, as it continues to be concentrated from the soil by each individual plant, and from vegetable products by each individual animal. ”

“ In the first place, the phosphatic minerals found in the archæan rocks are considered derivative from organic remains, as to-day phosphorus as a phosphate results from animal secretions, though phosphorus is omnipresent in the plant-world, and the ashes of various vegetables yield from eight per cent, to fifty-three per cent, of phosphoric acid, while the annual shipment of flour and wheat from our shores represents thousands of tons of this element. ”

“ He also rebukes me in a most earnest manner for the alleged misuse of the chemical term "phosphate of potash," which crept into my article in connection with the right use of the term "phosphate of lime," when I referred to the mineral phosphates of Kentucky, Tennessee, and Florida. Technically he is apparently right. There is no permanent form or no natural mineral form of phosphate of potash which can be removed from place to place. ”