During fungal rock phosphate (RP) solubilization, a significant quantity of fluoride (F −) is released together with phosphorus (P), strongly inhibiting the process.In the present study, the effect of two F − adsorbents [activated alumina (Al 2 O 3) and biochar] on RP solubilization by Aspergillus niger was examined. Al 2 O 3 adsorbed part of the F − released but also adsorbed soluble P ...
Dilute HCl solutions equilibrated with Florida phosphate rock and Tennessee brown phosphate rock in the presence of solid fluorite (CaF 2) developed a condition of supersaturation with respect to fluorapatite at 25C.In suspensions boiled before equilibration at 25C, however, the solutions were in equilibrium with fluorapatite, as evidenced by ion-activity products for fluorapatite in the ...
The phosphate rock was found to be formed by carbonate fluorapatite, calcite, dolomite, natural gypsum, quartz, calcite-Mg, apatite, pyrite, fluorite, and sphalerite-Cd and phosphogypsum by ...
The phosphate rock was found to be formed by carbonate fluorapatite, calcite, dolomite, natural gypsum, quartz, calcite-Mg, apatite, pyrite, fluorite, and sphalerite-Cd and phosphogypsum by synthetic gypsum and sphalerite-Cd. The phosphate was found to …
During fungal rock phosphate (RP) solubilization, a significant quantity of fluoride (F(-)) is released together with phosphorus (P), strongly inhibiting the process. In the present study, the effect of two F(-) adsorbents [activated alumina (Al2O3) and biochar] on RP solubilization by Aspergillus n …
Phosphate rock is an example of a dust that seemingly has not injured plants but is injurious to farm animals. This was made evident forty years ago when an attempt was made to feed phosphate rock as a dietary supplement source of calcium and phosphate. Fluoride injury quickly became apparent.2 Phosphate rock is used for this purpose today, but ...
Although many different fluoride-bearing rocks are known, fluorite (CaF 2) and fluorapatite (Ca 5 (PO 4) 3 F), which are present in fluorspar and phosphate rock, respectively, are believed to be the dominant mineral phases that cause fluoride contamination of groundwater [3,4].
US2954275A US709011A US70901158A US2954275A US 2954275 A US2954275 A US 2954275A US 709011 A US709011 A US 709011A US 70901158 A US70901158 A US 70901158A US 2954275 A US2954275 A US 2954275A Authority US United States Prior art keywords solution solids alkali metal extraction medium rock Prior art date Legal status (The legal status is an assumption and …
The total phosphate, hydrogen phosphate and dihydrogen phosphate contents were much higher than that of fluoroapatite, whereas the fluoroapatite content was higher than that of fluorite and metal fluoride. Fluorine and phosphorus were distributed in the form of agglomerates in the phosphate rock acid-insoluble residue.
Rock phosphate is the raw material used to manufacture most commercial phosphate fertilizers on the market. In the past, ground rock phosphate itself has been used as a source of P for acid soils. However, very little rock phosphate is currently used in agriculture due to low availability of P in this native material, high transportation costs ...
Rock phosphate, phosphatic limestone, and treble superphosphate occupied intermediate positions in this respect. 2. Rations containing excessive amounts of available fluorine reduced the growth and the feed consumption of pigs and chicks and definitely increased the feed requirement per unit of gain for the pig. 3. When the rations of pigs ...
"In the manufacture of super-phosphate fertilizer, phosphate rock is acidulated with sulfuric acid, and the fluoride content of the rock evolves as volatile silicofluorides. In the past, much of this volatile material was vented to the atmosphere, contributing heavily to pollution of the air and land surrounding the manufacturing site.
Fluorite (also called fluorspar) is the mineral form of calcium fluoride, CaF 2.It belongs to the halide minerals.It crystallizes in isometric cubic habit, although octahedral and more complex isometric forms are not uncommon.. The Mohs scale of mineral hardness, based on scratch hardness comparison, defines value 4 as Fluorite.. Pure fluorite is transparent, both in visible and ultraviolet ...
Phosphorite - Wikipedia
In nature fluoride exists in the form of fluorspar (fluorite), rock phosphate, triphite, phosphorite crystals, etc. The climate of the area and the chemical composition of rock minerals where water circulates are responsible for the concentration of fluoride. According to the WHO the presence of fluoride in water at lower concentrations can ...
