In this research, characterization studies of sedimentary PHOSPHATE ROCK from Zanjan Daleer area with respect to processing are investigated. According to mineralogical studies, PHOSPHATE ore (Collophane 28.13%), sedimentary mineral and the predominant constituents of the gangues were Calcite (43.53%), Quartz and Dolomite (4.65%). Main composition of PHOSPHATE ROCK were P2O5 (11.9% wt), CaO (36.36% wt), SiO2 (24.49% wt) and MgO (1.01% wt). Microscopic studies showed that apatite pletts had inclusions of Calcite and Quartz (about 15-70 microns). Content of inclusions was considerable. Mineralogy texture is very complicated. Liberation degree determined by grain counting (with optic microscope) and sink and float test methods. From The results of liberation degree studies can be inferred that in dimension about 140 microns about 96% of PHOSPHATE particles librated. In desliming step about 8.2% of total PHOSPHATE was removed. Optimum grinding time to reaching liberation of PHOSPHATE particles was obtained about 10 min and 30 second. Organic material determined by heating method (about 1.66% wt). Scanning electron microscopy studies showed that inclusions and organic materials existed. Specific gravity of PHOSPHATE particles and gangues difference was low. Based on the mentioned studies, effective method for processing of PHOSPHATE minerals from carbonate and silicate impurities is suggested flotation method.

SummaryAs the most important PHOSPHATE producer in Iran, the Esfordi PHOSPHATE complex produces apatite concentrate from the igneous ore by the flotation method. This plant is designed to separate PHOSPHATE from iron minerals. There is a type of ROCK in the Esfordi deposit that contains magnesium-bearing silicate minerals as gangue, which refers to green ROCK. Although the green ROCK includes five million tons of the mine reserve with an average grade of 7% P2O5, it has not been fed to the beneficiation plant, so far. In this research, the green ROCK processing was investigated using the current processing plant. A representative sample of green ROCK was prepared and characterized to evaluate the chemistry, mineralogy, and degree of freedom of apatite minerals. The laboratory magnetic separation and flotation tests along with the plenary sampling and characterization from the processing plant were performed. Introduction Esfordi PHOSPHATE Mine has the largest reserves of igneous PHOSPHATE in the country. At present, the feed for the dressing plant is supplied from apatite and iron-apatite. The green ROCK is an alternative feed for the beneficiation plant. The presence of magnesium-bearing silicates and fine particles are the two main obstacles of green ROCK flotation. In this research, flotation experiments were performed to process green ROCK, and the performance of the current PHOSPHATE processing plant was assessed. Methodology and ApproachesSampling was performed in two stages. In the first step, a sample was taken from the stock to identify the characteristics of green ROCK. The laboratory magnetic separation experiments at different magnetic field intensities and flotation experiments were performed. Fatty acid collector (to float apatite) and corn starch (for depressing iron ores and silicate minerals) were used in the flotation tests. The industrial-scale investigations were made by feeding the green ROCK to the plant, and sampling procedures were performed from different grinding, classification, and flotation streams. Results and ConclusionsThe results of High-intensity magnetic separation experiments showed that some of the silicate minerals found their way to the iron magnetic separation concentrate (recovery of 10.38% MgO at 5000 gausses). Flotation experiments showed that the recovery for green ROCK samples was very low and under normal conditions, recovery and P2O5 grades of 7.39 and 21.11% were gained, which increased to 38.65 and 27.98% after desliming. The efficiency of feeding green ROCK to the current circuit was monitored and low flotation recovery was observed along with high froth stability. The efficiency of the grinding circuit and desliming cyclones was also evaluated. Then, suggestions were made to improve the current processing circuit for green ROCK beneficiation.

Powdered ROCK PHOSPHATE may have the potential of soluble PHOSPHATE sorption because its particles are small.  Phosphorus (P) sorption-desorption behavior and sorption kinetics were studied on four different fine powdered PHOSPHATE ROCKs (PPR), from Esfordi, Chadormalu and Yasuj mines. Sorption isotherms were evaluated by equilibrating 1 g PPR with 20 ml CaCl2- 0.01 M containing 10, 50, 100, 200, 400, 600, 800 and 1000 mg P L-1, as KH2PO4 in duplicates. Consequently, P release was studied by equilibrating the samples with 20 ml 0.01 M CaCl2. FTIR analysis was conducted on the blank samples, and those equilibrated with 1000 mg P L-1. Kinetics of PHOSPHATE sorption on PPRs was evaluated with two initial P concentrations (50 and 100 mg P L-1) and contact times of 1, 2, 4, 8, 16, 24, and 48 h with 0.01 M CaCl2 as the background solution in duplicate. Results showed that the least P sorption was around 150, and the maximum P sorption was 12000 mg kg-1 PPRs. The highest P release was around 15% of sorbed P, and releasable P was reduced to 2-3% of sorbrd P with the increase of P sorption. P sorption data showed a good fit with Freundlich and Langmuir equations. The kinetic of P sorption showed a fast reaction that rapidly diminished soluble P. Results of the present study suggest that PPRs could reduce soluble P, which is better to be considered at different usage of PPR such as incorporation with organic wastes and its biosolubilization.

In this research the possibility of application of ROCK PHOSPHATE along with Thiobacillus bacteria PHOSPHATE solubilizing microorganisms, organic matter and sulfur on corn was studied. This experiment was carried out as a randomized complete block design with 15 treatments and four replications in Karaj Soil and Water Research Station. The treatments consisted of : T1= Control(without phosphorous fertilizer); T2=Triple superPHOSPHATE (200 kg ha-1); T3 = ROCK PHOSPHATE (RP) (400 kg ha-1); T4=ROCK PHOSPHATE + elemental sulfur (S) (500 kg ha-1 ); Ts= T4= Thiobacillus inoculants (Thio) (1 kg ha-1 T6= T5+ PHOSPHATE solubiling microorganisms (PSM) (l kg ha-I); T7=Ts+ organic matter (OM) (500 kg ha-1); Ts=T6+0M; T9=T4+OM; T10=T4+ PSM; T11= T10+OM;T12= T3+PSM; T13=T3+OM; TI4=T13+PSM and T15= OM. At the end of growing period plants were harvested and yield, yield components, soil available phosphorus and Zn, Fe, Cu, Mn and P uptake by corn were measured. Results indicated that there weren’t significant differences between treatments for wet forage yield. The highest yield (76858 kg ha-1) was obtained from T7. There were significant differences among treatments for ear weight and length, and the highest ear weight and length were obtained from T14 (416. 46 gr and 23 cm respectively). The highest and lowest concentration of phosphorous in the corn grain belonged to T7 (which was significantly different from the control) and T14. Respectively the highest concentration of Fe was obtained from T12 which was only significantly different from T2, T3 and T4. The highest amount of manganese and cupper concentration belonged to T15 and T2. The highest soil available phosphorous was obtained from T10 (9.7 mg. ka-1).

In this preliminary investigation, the production of liquid fertilizer from ROCK PHOSPHATE and dolomite in Nigeria using the nitroPHOSPHATE is evaluated. ROCK PHOSPHATE was obtained from Sokoto state, Nigeria. Dolomite was obtained from Edo state, Nigeria. This work contains a detailed description of the procedure and the associated chemical reactions. There are also important explanations of some physical observations and their possible implications in a large scale process. The time frame for each batch should not exceed 1 h considering the reaction rates and the temperatures are likely not to exceed 80oC at any point in the process. It was observed that the potassium, phosphorus and nitrogen content of both fertilizers are similar but the calcium content of the product from dolomite was higher than the other products. Furthermore, possible process design modifications based on these physical observations are proposed in line with product quality, safety, cost and other considerations. The process was ultimately successful and recommendations were made based on several aspects of the process.

The following experiments were conducted in three phases during 2001-2003 in a randomized complete block design to study the effects of organic materials and PHOSPHATE solubilizing bacteria on phosphorus availability in PHOSPHATE ROCK through isotopic dilution technique. The first phase of the experiments was performed on field to study the main effects of treatments on corn crop (Zea mays L.), the second phase was carried out on field to study the residual effects of treatments on barley crop ( Hordeum vulgare L.), and the third phase in a greenhouse to study the treatments' effects on P derived from soil (Pdfs), P derived from fertilizers (Pdff), and to determine fertilizer use efficiency (FUE) in corn crop grown in pot soils labeled with radioactive phosphorus (32P). After crop harvest in each phase, dry matter yield, total dry matter percentage, crop growth rate (CGR), P and Zn content in leaf, total P yield, P derived from fertilizer (Pdff), fertilizer use efficiency (FUE), agronomic efficiency (AE) and soil available phosphorus (Pava) were determined for corn crop while straw and grain yield, harvest index, as well as thousand kernel weight were determined for barley. The following results were obtained: Main effects of treatments on dry matter yield, total dry matter percentage, crop growth rate (CGR), fertilizer use efficiency (FUE), agronomic efficiency (AE) and the rate of fertilizer derived P (pdff), were statistically significant (P<0.01), but the main effects of treatments on height, P and Zn content in leaf, total phosphorus yield (TPY) and Pava were not significant. Residual effects of treatments on straw yield, grain yield, thousand kernel weight, harvest index and agronomic efficiency were not statistically significant. The results in this research demonstrated that PHOSPHATE ROCK along with organic matter and PHOSPHATE solubilizing bacteria increased the rate of P derived from fertilizer (Pdff) as well as increasing the yield indices for corn crop. As for main effects, treatments with organic matter and PHOSPHATE solubilizing bacteria were more effective than treatments with either organic matter or PHOSPHATE solubilizing bacteria. Therefore, treatments with organic matter and PHOSPHATE solubilizing bacteria can be recommended for increasing main effects on corn crop.

Purpose: Phosphorus (P) deficiency in agricultural land is one of the main factors which reduce the crop production and yield. To increase the crop growth, the availability of P using the ROCK PHOSPHATE (RP) can be enhanced using organic waste with the addition of PHOSPHATE solubilizing microorganisms (PSMs). Moreover, the combination along with time and dose application of RP and compost can also affect the P-availability through mineralization and/immobilization.Methods: To investigate the effect of different combinations of RP and compost (0: 100, 25: 75, 50: 50, 75: 25 and 100: 0) and time of application (30, 15, 7, 3 and 0 days before sowing), each was conducted in two consecutive pot experiments while, the rate of application (100–1000 kg ha-1) was investigated under field conditions, in comparison to control (recommended P fertilizer).Results: ROCK PHOSPHATE enriched compost (RP-EC) with a combination ratio of 50: 50; RP and compost applied before 7 days of sowing in pot experiments resulted in the maximum nodulation, growth and productivity of chickpea. Under field conditions, the maximum increase of 35.3% in no. nodules plant−1, 26.7% in dry wt. of nodules plant-1 and 20.8% in grain yield (t ha-1) compared to control was obtained by RP-EC@1000 kg ha-1. The same treatment indicated an increase of 12.9 and 4.3% in P contents in straw and grains, respectively, compared to control. However, most results were non-significant when RP-EC applied at the rate of 1000 kg ha-1.Conclusion: Application of RP-EC, with the ratio of 50: 50 (RP: Compost) and application rate of 800 kg ha-1 before 7 days of sowing, exhibited maximum growth and development, and can be highly recommended for optimum production of chickpea.

A factorial completely randomized design experiment with three replications was carried out in greenhouse to evaluate the phosphorus (P) acquisition and utilization efficiency of 20 wheat genotypes in a river sand fertilized with ROCK PHOSPHATE (RP) and soluble P (PS). Results showed significant differences in shoot dry weight (SDW), shoot P concentration, shoot P content, P acquisition (PACE), P utilization (PUTE) and P efficiency. Marvdasht and Hamun with 8.3 and 5.6 g dry weight showed the highest and lowest response to soluble P fertilizer application, respectively. The average of PACE for all genotypes was 0.04 which Azadi and Karaj1 were the most and least efficient in P acquisition compared to other genotypes. PUTE ranged from 0.6 (Azadi) to 1.12 (Moghan 1) with the average of 0.82 (RP) and 0.31 g DW mg-1 P (PS). Among wheat genotypes, Karaj 1 (4.5%) and Azadi (14.5%) showed the lowest and highest P efficiency, respectively. There was no correlation (R2=0.18) between P efficiency and shoot P concentration of genotypes, but the relationship between P efficiency and shoot P content was highly significant (R2=0.77).

Direct use of ROCK PHOSPHATE is considered as one of the alternatives to superPHOSPHATE, however, its use in acidic soils in the north of Iran has received less attention. This experiment was conducted as randomized complete block design. The treatments included: 1) control, 2) triple superPHOSPHATE (Tsp) fertilizer (based on soil test), 3) ROCK PHOSPHATE (to the extent that P addition was the same as Tsp), 4) compost at the rate of 10 tons per hectare, 5) ROCK PHOSPHATE+PHOSPHATE solubilizing fungi, 6) ROCK PHOSPHATE+PHOSPHATE dissolving fungi (Glomos), 7) ROCK PHOSPHATE + 10 tons per hectare compost, 8) ROCK PHOSPHATE + compost + PHOSPHATE solubilizing fungi (Pseudomonas), 9) ROCK PHOSPHATE+PHOSPHATE solubilizing fungi +compost. The results indicated the possibility of substituing ROCK PHOSPHATE for Tsp in acidic soils of tea plantations, and organic matter plays an important role in better dissolution of ROCK PHOSPHATE by microorganisms in acidic soils. Application of bacteria, fungi, and compost treatments along with ROCK PHOSPHATE significantly increased the yield of green tea leaves as well as soil available P, compared to the control. Also, the concentration of trace elements in treatments containing compost showed a significant increase. The use of ROCK PHOSPHATE alone significantly increased the soil available P compared to the control, but the highest amount of soil P was obtained by simultaneous application of ROCK PHOSPHATE with compost and microorganisms (biofertilizers).

Direct use of ROCK PHOSPHATE is considered as one of the alternatives to superPHOSPHATE, however, its use in acidic soils in the north of Iran has received less attention. This experiment was conducted as randomized complete block design. The treatments included: 1) control, 2) triple superPHOSPHATE (Tsp) fertilizer (based on soil test), 3) ROCK PHOSPHATE (to the extent that P addition was the same as Tsp), 4) compost at the rate of 10 tons per hectare, 5) ROCK PHOSPHATE+PHOSPHATE solubilizing fungi, 6) ROCK PHOSPHATE+PHOSPHATE dissolving fungi (Glomos), 7) ROCK PHOSPHATE + 10 tons per hectare compost, 8) ROCK PHOSPHATE + compost + PHOSPHATE solubilizing fungi (Pseudomonas), 9) ROCK PHOSPHATE+PHOSPHATE solubilizing fungi +compost. The results indicated the possibility of substituing ROCK PHOSPHATE for Tsp in acidic soils of tea plantations, and organic matter plays an important role in better dissolution of ROCK PHOSPHATE by microorganisms in acidic soils. Application of bacteria, fungi, and compost treatments along with ROCK PHOSPHATE significantly increased the yield of green tea leaves as well as soil available P, compared to the control. Also, the concentration of trace elements in treatments containing compost showed a significant increase. The use of ROCK PHOSPHATE alone significantly increased the soil available P compared to the control, but the highest amount of soil P was obtained by simultaneous application of ROCK PHOSPHATE with compost and microorganisms (biofertilizers).