Fertilizer raw materials

Secondary and micronutrients in fertilizers. Raw material resources for fertilizers. Environmental aspects,... 

It is impossible to present more than gross estimates of world resources of fertilizer raw materials for several reasons. Although man continues to explore his environment and many areas of the globe have been ex--plored in detail, particularly in the last 30 years, there are areas of the globe that have not been surveyed or have been surveyed inadequately. When deposits are known to exist, the extent and quality of information on the quantity or quality of material in the deposit may vary greatly. Reasonably good data may only exist when considerable effort and funds have been spent to develop deposits. Detailed exploration and evaluation of a deposit is an expensive process only undertaken when commercial exploitation is probable. 

Fhosphate rock prices will increase when demand approaches the limits of supply. When phosphate rock prices increase, some resources become rieserves, marginal mining projects become xtoble, and production is stimulated. In the future, fuel and kiel-related transportation costs may become even more important components in the world phosphate rock production scenario. Political disruptions, always an unknown factor, can profoundly influence the supply and demand for fertilizer raw materials on a worldwide basis. 

Density is the mass per unit volume of a material. Three types of density measurements can be detemrtined for fertilizer products and fertilizer raw materials bulk density, apparent density, and true density. 

There is considerable variety in the types of fertilizer raw materials used commercially in preparation of suspension fertilizers. This is indicated in Fig. 11.21, where some of the more popular materials are listed. Likewise, production procedures and equipment vary considerably. Provision of a high-shear mixer is essential not only for gelling of the suspending clay but also for disintegration of... 

As is evident from the listing in Table 3, the fertilizer manufacturer has a wide array of compounds from which to choose. Final choices of products and processes therefore rest heavily on such other factors as availabiUty and cost of raw materials, economy of processing, safety of product, economy of handling and shipping, acceptabiUty of physical form and physical behavior of the product, and farmer acceptance. 

There are numerous variations of the wet process, but all involve an initial step in which the ore is solubilized in sulfuric acid, or, in a few special instances, in some other acid. Because of this requirement for sulfuric acid, it is obvious that sulfur is a raw material of considerable importance to the fertilizer industry. The acid—rock reaction results in formation of phosphoric acid and the precipitation of calcium sulfate. The second principal step in the wet processes is filtration to separate the phosphoric acid from the precipitated calcium sulfate. Wet-process phosphoric acid (WPA) is much less pure than electric furnace acid, but for most fertilizer production the impurities, such as iron, aluminum, and magnesium, are not objectionable and actually contribute to improved physical condition of the finished fertilizer (35). Impurities also furnish some micronutrient fertilizer elements. 

Nitric Phosphate. About 15% of worldwide phosphate fertilizer production is by processes that are based on solubilization of phosphate rock with nitric acid iastead of sulfuric or phosphoric acids (64). These processes, known collectively as nitric phosphate or nitrophosphate processes are important, mainly because of the iadependence from sulfur as a raw material and because of the freedom from the environmental problem of gypsum disposal that accompanies phosphoric acid-based processes. These two characteristics are expected to promote eventual iacrease ia the use of nitric phosphate processes, as sulfur resources diminish and/or environmental restrictions are tightened. 

Resources for Nitrogen Fertilizers. The production of more than 95% of all nitrogen fertilizer begins with the synthesis of ammonia, thus it is the raw materials for ammonia synthesis that are of prime interest. Required feed to the synthesis process (synthesis gas) consists of an approximately 3 1 mixture (by volume) of hydrogen and nitrogen. 

Resources for Potash Fertilizers. Potassium is the seventh most abundant element in the earth s cmst. The raw materials from which postash fertilizer is derived are principally bedded marine evaporite deposits, but other sources include surface and subsurface brines. Both underground and solution mining are used to recover evaporite deposits, and fractional crystallization (qv) is used for the brines. The potassium salts of marine evaporite deposits occur in beds in intervals of haUte [14762-51-7] NaCl, which also contains bedded anhydrite [7778-18-9], CaSO, and clay or shale. The K O content of such deposits varies widely (see Potassium compounds). 

Hard-burned magnesias may be used in a variety of appHcations such as ceramics (qv), animal feed supplements, acid neutralization, wastewater treatment, leather (qv) tanning, magnesium phosphate cements, magnesium compound manufacturing, fertilizer, or as a raw material for fused magnesia. A patented process has introduced this material as a cation adsorbent for metals removal in wastewater treatment (132). 

By-Products and Waste Disposal. A by-product of sulfamic acid manufacturing is fuming sulfuric acid or dilute sulfuric acid. The amount of sulfuric acid (as 100% H2SO is 1—1.5 times as much by weight as the sulfamic acid product. This by-product also contains ammonium salts and is therefore normally used as raw material for fertilizer (see Fertilizers). 

Agriculture is the largest industry for sulfur consumption. Historically, the production of phosphate fertilizers has driven the sulfur market. Phosphate fertilizers account for approximately 60% of the sulfur consumed globally. Thus, although sulfur is an important plant nutrient in itself, its greatest use in the fertilizer industry is as sulfuric acid, which is needed to break down the chemical and physical stmcture of phosphate rock to make the phosphate content more available to plant life. Other mineral acids, as well as high temperatures, also have the abiUty to achieve this result. Because of market price and availabiUty, sulfuric acid is the most economic method. About 90% of sulfur used in the fertilizer industry is for the production of phosphate fertilizers. Based on this technology, the phosphate fertilizer industry is expected to continue to depend on sulfur and sulfuric acid as a raw material. 

Sulfur (qv) is among the most widely used chemicals and often considered to be one of the four basic raw materials of the chemical iadustry. In 1993, worldwide production of sulfur reached 55 million metric tons (1). Production of sulfuric acid consumes the vast majority (- 90%) of sulfur (2) (see Sulfuric acid and sulfur trioxide). This acid is a steppiag stone ia the production of other sulfur-containing compounds, most notably ammonium sulfate fertilizer which accounts for 60% of the total worldwide sulfur consumption (2) (see Ammonium compounds Fertilizers). 

Since the first application of turbocompressors (Figure 4-1) in large-scale production of nitric acid as a raw material for fertilizers, explosives, plastics, and a variety of other chemical products, the requirements on processes as well as on rotating equipment have become increasingly demanding. Environmental as well as economic considerations have heavily influenced the development of such plants. 

Acetylene and ethylene compete as a chemical raw material. Ethylene is generally more economical, resulting in declining use of acetylene as a raw material. Calcium carbide, a raw material for acetylene has other uses. Treated with nitrogen, it gives calcium cyanamide, valuable as a fertilizer and weed killer, and a raw material for the production of melamine, used ir ng some modern plastics. 

The element phosphorus, like nitrogen, is essential to plant and animal life. Although phosphorus was not identified and isolated until 1669, phosphorus-containing materials have been used as fertilizers since ancient times, usually from bird droppings, fish, and bone. The first phosphoric acid was made by treating bone ashes with sulfuric acid. This marked the beginning of the commercial fertilizer industry. Eventually, mined phosphate rock, a poor fertilizer by itself, was substituted for bones as a raw material for phosphoric acid in the mid-1880s. 

Uses The largest use is in the manufacture of fertilizers. It is also used to make one of the raw materials for nylon, virtually all gunpowder and explosives (nitroglycerin, nitrocellulose, TNT, ammonium nitrate, etc.) and the starting materials for polyurethane elastomers and paints. 

Hydroxylamine (hyam) is used in the production of caprolactam, a key raw material for the manufacture of Nylon-6. Several technologies exist for the production of caprolactam with a key difference being the amount of byproduct ammonium sulfate, a low cost fertilizer, formed. The hyam used in the process is produced by... 

Chemical plants are a series of operations that take raw materials and convert them into desired products, salable by-products, and unwanted wastes. Fats and oils obtained from animals and plants are hydrolyzed (reacted with water) and then reacted with soda ash or sodium hydroxide to make soaps and glycerine. Bromine and iodine are recovered from sea water and salt brines. Nitrogen and hydrogen are reacted together under pressure in the presence of a catalyst to produce ammonia, the basic ingredient used in the production of synthetic fertilizers. 

The other major advantage was that the United States was not to be its only customer. In fact, before the plant was built Japan Gas Chemical contracted to buy half the urea output. Here the advantage of Alaska over any other United States location except Hawaii is a reduction in shipping costs. Kenai is 1,400 miles (2,250 km) closer to Japan than is any California location. This, coupled with the low raw material costs, would make its delivered cost less than most other Japanese fertilizer sources. When all these factors were considered, the Collier Carbon and Chemical Company reasoned it was cheaper to process the natural gas into ammonia at its source even with those difficult climatic and economic conditions than to ship the gas to a more advantageous location and then make ammonia. 

Formulators must also deal with increasing costs of raw materials. Urea, the principal ingredient in most yard fertilizers, has risen in cost. Scotts sold their professional golf turf business partly because of the increased cost of raw materials such as urea and fuel. ... 

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