Partial acidulation of an ?unground? phosphate rock: I. Preparation and characteristics

1985 ◽  
Vol 8 (2) ◽  
pp. 147-155 ◽  
Author(s):  
SSS Rajan
Keyword(s):  
Phosphate Rock ◽  
Partial Acidulation

Causes for the reduced reactivity of phosphate rock residues in partially acidulated phosphate rocks

Soil Research ◽  
1994 ◽  
Vol 32 (1) ◽  
pp. 95 ◽  
Author(s):  
HJ Di ◽  
LM Condron ◽  
AS Campbell ◽  
KM Goh ◽  
IS Cornforth
Keyword(s):  
North Carolina ◽  
Phosphate Rock ◽  
Water Soluble ◽  
Partially Acidulated Phosphate Rock ◽  
Ammonium Citrate ◽  
Insoluble Residue ◽  
Partial Acidulation ◽  
C:P Ratio ◽  
Fluoride Complexes ◽  
Acid Solubility

The agronomic effectiveness of partially acidulated phosphate rock (PAPR) fertilizers depends on the proportion of water soluble P present and the long-term release of P from the unacidulated residual phosphate rock (water-insoluble residue) in the soil environment. The relative reactivity of water-insoluble residues in a range of partially acidulated phosphate rock (PAPR) fertilizers was assessed according to chemical solubility, and was found to be lower than the corresponding original PRs. Two causes were identified for the reduced formic acid solubility of water-insoluble residues: (i) some preferential dissolution of more reactive apatite components (i.e. higher carbonate substituted apatite) during partial acidulation as indicated by reductions in the molar apatite C:P ratio of the residual PRs compared with the corresponding original PRs, and (ii) acid-insoluble metal (Fe-Al-Mg)phosphate and/or fluoride complexes formed on the surface of residual PRs during partial acidulation with commercial-grade phosphoric acid, which were partially soluble in alkaline ammonium citrate. These two mechanisms accounted for most of the solubility differences observed for 'medium' reactive PRs (Khouribga, Arad), compared with only half for more reactive PRs (North Carolina, Gafsa). The conclusion from this study is that partial acidulation may not be an ideal method for the manufacture of fertilizers containing fast and slow release (i.e. PR) components, particularly when highly reactive PRs such as North Carolina are used.

ALTERNATIVE P-FERTILISERS FOR NORTHLAND SOILS

1986 ◽  
pp. 229-232
Author(s):  
P.W. Shannon
Keyword(s):  
Phosphate Rock ◽  
Growth Responses ◽  
Triple Superphosphate ◽  
Rock Phosphates ◽  
Distribution Costs ◽  
Phosphate Retention ◽  
Sechura Phosphate Rock ◽  
Local Product ◽  
Application Frequency ◽  
Chatham Rise Phosphorite

Increasing material, processing, and distribution costs have raised superphosphate prices to a point where many farms cannot support the costs of meeting maintenance phosphate requires men& Alternatives to superphosphate, particularly those that have lower processing costs and contain more P, may offer a solution to the problem provided they are agronomically as effective. Phosphate rock may indeed be such an alternative. Preliminary results from a series of five trials in Northland show that on soils of moderate P fertility, with low phosphate retention (PR) and high pH (5.9.6.0), initial pasture growth responses to rock phosphates are smaller than those from single or triple superphosphate. On one soil of higher PR and lower pH, the differences in yield between the rock-phosphates and the super. phosphates were smaller. Of the rock phosphates tested, Sechura and North Carolina (unground and ungranulated) tended to be more effective than ground and granulated Chatham Rise phosphorite. The effect on production of applying fertilisers once every three years, as opposed to annual applications is being investigated using triple superphosphate and Sechura phosphate rock. After two years, production levels appear largely unaffected by differences in application frequency. A comparison of locally-produced superphosphate with a reference standard showed that both performed similarly, indicating that the local product was of satisfactory quality.

Uranium in phosphate rock

1975 ◽  
Author(s):  
James Bachelder Cathcart
Keyword(s):  
Phosphate Rock

A summary of phosphate-rock resources of the United States; an analysis of past estimates

1981 ◽  
Author(s):  
James Bachelder Cathcart ◽  
Richard Porter Sheldon ◽  
Robert A. Gulbrandsen
Keyword(s):  
United States ◽  
Phosphate Rock ◽  
The United States

NIROSTA 4465

Alloy Digest ◽  
2000 ◽  
Vol 49 (7) ◽  
Keyword(s):  
Fracture Toughness ◽  
Corrosion Resistance ◽  
High Temperature ◽  
Intergranular Corrosion ◽  
Phosphate Rock ◽  
Heat Treating ◽  
Chromium Alloy ◽  
Low Carbon ◽  
High Chromium ◽  
Temperature Performance

Abstract Nirosta 4465 is a low-carbon, high-chromium alloy with nickel and molybdenum. It has good corrosion and intergranular corrosion resistance. The alloy is used for processing phosphate rock. This datasheet provides information on composition, physical properties, elasticity, and tensile properties as well as fracture toughness. It also includes information on high temperature performance and corrosion resistance as well as forming, heat treating, machining, and joining. Filing Code: SS-797. Producer or source: ThyssenKrupp Nirosta.

Kinetics of Phosphate Rock Dissolution in Acidic Soil Amended with Liming Materials and Cellulose

1996 ◽  
Vol 60 (6) ◽  
pp. 1589-1595 ◽  
Author(s):  
Z. L. He ◽  
V. C. Baligar ◽  
K. D. Ritchey ◽  
D. C. Martens ◽  
W. D. Kemper
Keyword(s):  
Phosphate Rock ◽  
Acidic Soil ◽  
Phosphate Rock Dissolution ◽  
Kinetics Of

Overview of Current Phosphoric Acid Production Processes and a New Idea of Kiln Method

2020 ◽  
Vol 17 ◽  
Author(s):  
Guangya Zheng ◽  
Jupei Xia ◽  
Zhengjie Chen
Keyword(s):  
Phosphoric Acid ◽  
Acid Production ◽  
Phosphate Rock ◽  
Low Grade ◽  
Production Methods ◽  
Production Processes ◽  
Major Equipment ◽  
Development Prospects ◽  
Great Competitiveness

: China primarily contains medium and low-grade phosphorus ores that are used to produce phosphoric acid. Here, we provide an overview of phosphoric acid production processes, including wet, thermal, and kiln methods, as well as the fundamental principles, major equipment, and technological aspects of each process. Progress in the kiln method using lowgrade phosphate rock is described, which involves the KPA and CDK processes. The literature shows that the addition of admixtures adds great competitiveness to kiln phosphate production methods and has considerable development prospects.

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