Phosphate ores

Phosphate ores Phosphate plastici Phosphate rock... 

A similar reaction occurs when polyacrylamide is mixed with glyoxilic acid [298-12-4], C2H2O2, at pH about 8. This reaction produces a polymer with the CONHCH(OH)COOH fiinctionahty, which has found appHcation in phosphate ore processing (53). 

Wet-Process Phosphoric Acid. As indicated in Figure 7, over 95% of the phosphate fertilizer used in the United States is made by processes that require an initial conversion of all or part of the phosphate ore to phosphoric acid. On a worldwide basis also, the proportion of phosphate fertilizer made with phosphoric acid is very high. Thus processes for production of phosphoric acid are of great importance to the fertilizer industry (see PHOSPHORIC ACID AND THE PHOSPHATES). 

Oil Shale Operations in Israel. Oil shale, the only fossil fuel resource in Israel, is being used to generate electric power. The oil shale feed stock, typical of the low grade IsraeH oil shale (see Table 2), is situated in a deposit overlying phosphate ore. The oil shale operations are being carried out because the oil shale has to be mined to obtain the phosphate ore. 

Separation and Recovery of Rare-Earth Elements. Because rare-earth oxalates have low solubihty in acidic solutions, oxaUc acid is used for the separation and recovery of rare-earth elements (65). For the decomposition of rare-earth phosphate ores, such as mona ite and xenotime, a wet process using sulfuric acid has been widely employed. There is also a calcination process using alkaLine-earth compounds as a decomposition aid (66). In either process, rare-earth elements are recovered by the precipitation of oxalates, which are then converted to the corresponding oxides. 

The western phosphates are sedimentary deposits in adjoining areas of Wyoming, Idaho, and Utah derived from a former inland sea. They consist of layers of limestone, phosphate, and chert, now budded and faulted so they are rarely horizontal. The phosphate ore is strip-mined using large earth-moving equipment such as shovels, scrappers, dump tmcks, and bulldozers to mine the overburden and phosphate ore. Mining ratios of overburden to metric ton of recovered ore are from 1—3 m /1 (2—4 yd /short ton). The typical mining practice is to remove ore and overburden from a pit in discrete layers (Lifts) of 10—20 m in depth. Overburden from the pit is back-hauled to a previously mined pit. Extensive land reclamation practices are later carried out to return the mine areas to natural states. 

Another preparation method is a sintering process where phosphate ore, sand, and coal are blended together and ignited on the grates of a sintering machine. Air is pulled through the blend, and the entire mass is allowed to bum. The resulting fused bed of material is then cmshed and screened to the appropriate size distribution, and the undersized material is reprocessed. 

StUl another ore preparation is the nodulizing process where the ore is heated in a rotary kiln to incipient fusion. The tumbling action in the kiln causes the phosphate ore to cohere and form spheroidal agglomerates. Combustion of carbon monoxide from the furnaces is used along with supplemental fuel to supply heat to 1300—1500°C. A boring bar is used near the kiln discharge to aid in breaking up the fused ore. The material is then cooled, cmshed, and screened to the appropriate size for furnace feed. 

One other method used to size the phosphate ore is disk agglomeration. After preparation, the disk agglomerates are sintered at high temperature in separate process steps, followed by screening to the appropriate size specifications. 

Some producers beneficiate the phosphate ore prior to agglomeration to increase the phosphate content and remove undesirable contaminants. One approach uses a water wash to remove fines which are lower in assay and higher in contamination. If too much clay is removed from the ore by the beneficiation, a binder such as bentonite clay must be added back to the ore to faciUtate agglomeration. 

Estimated world production capacity for elemental phosphoms is shown in Table 5 (6). Three elemental phosphoms production sites remain operational in North America (14), although Rhc ne Poulenc has announced its intention to cease production in late 1995. The remaining plants have survived owing to the availabiUty of economical electric power in the Northwest and proximity to phosphate ore deposits, resulting in lower cost phosphoms. The capacity of these producers in 1995 was estimated to be 264,000 metric tons. U.S. production capacity peaked at approximately 622,000 metric tons in 1970. 

Mining. Numerous patents have advocated the use of alkanolamines in mining appHcations. Triethanolarnine has been used as a depressent in the flotation of copper (164), in the electrotwinning of gold (165), and as an aid in the froth flotation of nickel ores. Phosphate ore flotation has been improved through the use of a fatty acid condensate with ethanolamine (166). Beneficiation of tin ore has been accompHshed using fatty acid alkanolamides (167). 

Phosphogypsum [13397-24-5] is the name given to the by-product gypsum residue when phosphate ore is acidulated to extract phosphoric acid. There are several processes commercially used. AH of them digest or acidulate tri-calcium phosphate. 

Low 500-20,000 2-4 Mixed fertilizers, phosphate ores, shales, urea Coal, charcoal, coke, lignite, animal feed, candy Phosphate ores, urea... 

The eleetronic configuration of the group-IIA elements, [inert gas] ns, render them so reactive that they never occur native but are always combined with other elements. Thus, Be is found in complex silicate minerals Mg, Ca, Sr and Ba, however, occur in carbonate, sulfate or phosphate ores. Consequently, whereas the extractive metallurgy of Be is relatively complex, that for the other elements is quite straightforward. 

The technologies involved in the minerals processing industry can be broken down into those where the desired metal component is in high concentration, such as scrap iron, iron ore, phosphate ore, and bauxite, and those where the concentration of the valuable constituent is low, such as gold and silver ore, lean copper ore, and certain types of scrap and wastes. 

Depressants are used to make materials less floatable, and again have been used for some time.4,18 A recent example is the use of phosphoric acid to depress the flotation of a sedimentary phosphate ore, enhancing the selectivity of recovery of calcite and silica.24 Natural and synthetic polymers have also been used as depressants.20... 

Sintering machines, 26 565 molybdenum, 17 9-10 of polytetrafluoroethylene, 18 300-301 phosphate ore, 19 7 Sintering process, 10 41, 94, 95 for ceramic membranes, 15 814, 815 sulfur recovery from, 23 772 with tin powder, 24 798-799 Sinter processes... 

Uses Disinfectant phenolic resins tricresyl phosphate ore flotation textile scouring agent organic intermediate manufacturing salicylaldehyde, coumarin, and herbicides surfactant synthetic food flavors para isomer only) food antioxidant dye, perfume, plastics, and resins manufacturing. 

Vanadiums principal ores are roscoelite, patronite, vanadinite, and carnotite, which are found in the states of Idaho, Montana, Arkansas, and Arizona as well as in Mexico and Peru. It is also a by-product from the production of phosphate ores. 

Fig. 1. Location map of the Ras-Draa phosphate ore deposit in the Gafsa-Metlaoui basin, Tunisia (source www.earth.google, fr).

Table 1 Range of Concentrations of Various Chemicals in Phosphate Ores...

Calcium sulfate is formed as a byproduct in industrial processes such as flue gas desulfurization and the production of zinc, fluoride, organic acids and phosphoric acid, in amounts of many million tons per year. In this study the attention is focussed on calcium sulfate from the production of phosphoric acid for fertilizer applications. It is precipitated, from solution after digestion of phosphate ore by addition of sulfuric acid according to [1] ... 

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