Phosphate calcium phosphorus product

Calcium phosphorus product (CPP) is generally regarded as an indicator of the likelihood of calcium phosphate precipitation in human tissues and, more specifically, the renal tubules. Based on the normal serum concentration ranges for calcium and phosphorus, the normal range for CPP is 21 to 47.3. Following the use of OSPS, serum phosphorus and CPP transiently increase and the duration and magnitude of this change are likely to be important risk factors for the development of APhN. 

Finally, intravenous phosphate may rapidly reduce ionized calcium concentrations through the formation of insoluble calcium-phosphate salts. However, intravenous phosphate is extremely hazardous because extraskeletal precipitation of calcium-phosphate may result in metastatic calcification, hypotension, acute renal failure, or death. Therefore intravenous phosphates should be reserved for the extraordinary patient with severe hypercalcemia and concomitant hypophosphatemia. Oral phosphorus is not used chronically for the treatment of hypercalcemia because calcium-phosphate crystals may precipitate in the kidneys or other major organs when the calcium-phosphorus product is > 50 to 60 mg /dL . Serum calcium, phosphorus, and creatinine should be monitored closely. Oral phosphorus treatment is only indicated when there is concomitant hypophosphatemia (<2 mg/dL). 

The manufacture of phosphorus-derived chemicals is almost entirely based on the production of elemental phosphorus from mined phosphate rock. Ferrophosphorus, widely used in the metallurgical industries, is a direct byproduct of the phosphorus production process. In the United States, over 85% of elemental phosphorus production is used to manufacture high-grade phosphoric acid by the furnace or dry process as opposed to the wet process that converts phosphate rock directly into low-grade phosphoric acid. The remainder of the elemental phosphorus is either marketed directly or converted into phosphoms chemicals. The furnace-grade phosphoric acid is marketed directly, mostly to the food and fertilizer industries. Finally, phosphoric acid is employed to manufacture sodium tripolyphosphate, which is used in detergents and for water treatment, and calcium phosphate, which is used in foods and animal feeds. 

A single, present-day phosphorus furnace produces from 60 to 160 tonnes of phosphorus per day, almost the same as the annual production figures of the early arc furnaces, and requires a power supply of about 90,000 kW for a single, 160 tonne/day furnace. Power consumption per tonne of phosphorus produced varies with the % calcium phosphate in the rock (% BPL level) and furnace size among other factors but ranges around 12,000-14,000 kWh/ tonne (Table 10.4). Hence, power is a major cost component of electric furnace phosphorus production. This realization has prompted a reexamination of fossil-fueled (petroleum coke-based) sources of heat for rotary kiln combustion to provide the energy of the endotherm of the reaction [15]. 

Calcium carbonate is the salt of choice because it contains the highest amount of elemental calcium and is the least expensive (see Table 88-5). The fraction of calcium absorbed is dose-limited, so maximum single doses of 600 mg or less of elemental calcium are recommended. Calcium carbonate tablets should be taken with meals to enhance absorption. Calcium citrate absorption is acid-independent and need not be administered with meals. Although tricalcium phosphate contains 39% calcium, nonabsorbable calcium-phosphorus complexes may limit overall calcium absorption compared to other products. This product may be required for up to 10% of seniors with hypophosphatemia that cannot be resolved with increased dietary intake. Disintegration and dissolution rates vary significantly between products and lots. Products with good disintegration and dissolution rates and lead contents of less than 1 mcg/day should be recommended. 

Elemental phosphorus is prepared by the reduction of calcium phosphate, Ca3(P04)o, with coke in the presence of sand, SiO>. The products are phosphorus, calcium silicate, CaSiOa, and carbon monoxide. 

C21-0082. Calcium dihydrogen phosphate is a common phosphoras fertilizer that is made by treating fluoroapatite with phosphoric acid. Hydrogen fluoride is a by-product of the synthesis. Write a balanced equation for the production of this fertilizer and calculate the mass percent of phosphorus in the fertilizer. 

The product, Ca(H2P04)2, is more soluble than the phosphate. Sulfuric acid is produced in the largest quantity of any compound, with production that approaches 100 billion pounds annually. Approximately two-thirds of this amount is used in the production of fertilizers. The mixture containing calcium dihydrogen phosphate and calcium sulfate (gypsum) is known as superphosphate of lime, and it contains a higher percent of phosphorus than does calcium phosphate. 

The phosphate manufacturing and phosphate fertilizer industry includes the production of elemental phosphorus, various phosphorus-derived chemicals, phosphate fertilizer chemicals, and other nonfertilizer phosphate chemicals [1-30], Chemicals that are derived from phosphorus include phosphoric acid (dry process), phosphorus pentoxide, phosphorus penta-sulfide, phosphoms trichloride, phosphorus oxychloride, sodium tripolyphosphate, and calcium phosphates [8]. The nonfertilizer phosphate production part of the industry includes defluori-nated phosphate rock, defluorinated phosphoric acid, and sodium phosphate salts. The phosphate fertilizer segment of the industry produces the primary phosphorus nutrient source for the agricultural industry and for other applications of chemical fertilization. Many of these fertilizer products are toxic to aquatic life at certain levels of concentration, and many are also hazardous to human life and health when contact is made in a concentrated form. 

All phosphorus fertilizers come from wet process phosphoric acid or directly from phosphate rock. Normal superphosphate, triple or concentrated superphosphate, and ammonium phosphate are the three common types used. Normal or ordinary superphosphate (NSP or OSP) is mostly monocalcium phosphate and calcium sulfate. It is made from phosphate rock and sulfuric acid and is equated to a 20% P2O5 content. It led the market until 1964. The production of normal superphosphate is similar to that for the manufacture of wet process phosphoric acid (Chapter 2, Section 3) except that there is only partial neutralization. Normal superphosphate is no longer used to any great extent. The following reaction is one example of an equation that represents this process. 

Most of the world production of phosphates goes into fertilizer, but some is used as detergent builders (Section 7.7). In toothpastes, calcium pyrophosphate has proved effective as a mild abrasive in eliminating tartar, while Na2[FP03], made by reaction of NaF with cyclic sodium metaphosphates (NaP03), is widely used as a fluoridating agent to suppress dental caries (Section 12.3). A minor amount of rock phosphate is used to make elemental phosphorus by reduction with coke in the presence of silica in the electric furnace (see Section 17.7) ... 

There arc two main processes for the industrial production of phosphoric add, H3PO4. from phosphate rock (1) the wet process which involves tlie reaction of phosphate rock with H2SO4 to yield phosphoric acid and insoluble calcium sulfites, Several of the impurities present in the rock dissolve and remain with the product add. These are not important when the add is used for fertilizer manufacture. However, the impurities are deleterious to the manufacture of phosphorus chemicals. For a purer product, (2) the furnace process is used, wherein the phosphate rock is combined with coke and silica, producing elemental phosphorus as previously described. Oxidation of the phosphorus produces P2O5 which, when combined with H2O, yields H3PO4. 

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