Calcined Christmas Island C-grade rock phosphate fertilizers: Mineralogical properties, reversion and assessment by chemical extraction

Soil Research ◽  
1979 ◽  
Vol 17 (3) ◽  
pp. 467 ◽  
Author(s):  
RJ Gilkes ◽  
B Palmer
Keyword(s):  
Rock Phosphate ◽  
Chemical Properties ◽  
Ammonium Citrate ◽  
Chemical Extraction ◽  
Phosphate Fertilizers ◽  
Christmas Island ◽  
Phosphorus Fertilizers ◽  
Different Temperatures ◽  
Grade Rock ◽  
And Chemical Properties

Calcination of Christmas Island C-grade ore at temperatures up to 1050�C produces phosphorus fertilizers that differ greatly in effectiveness as determined by citrate extraction and plant growth. Maximum effectiveness is obtained by calcination at temperatures between 500� and 650�C, and is best predicted by extractions of between 1 and 3 h duration in neutral ammonium citrate. Alkaline ammonium citrate and citric acid are poorer indicators of phosphorus availability. The mineralogical and chemical properties of the calcines may be used to explain variations in amounts of citrate soluble phosphorus for different temperatures of calcination. Incubation of moist 500�C calcined C-grade ore induces recrystallization (i.e. reversion) of some crandallite, resulting in a decrease in the solubility of phosphorus in neutral ammonium citrate and its availability to plants.

The relative value of water-soluble and ammonium-citrate-soluble phosphorus for wheat production

1982 ◽  
Vol 98 (2) ◽  
pp. 467-470 ◽  
Author(s):  
B. Palmer ◽  
R. S. Jessop
Keyword(s):  
Rock Phosphate ◽  
Water Soluble ◽  
Ammonium Citrate ◽  
Lower Grade ◽  
Wheat Production ◽  
Christmas Island ◽  
The Pacific ◽  
Relative Value ◽  
The Pacific Ocean ◽  
Grade Rock

Wheat production in Australia relies heavily on superphosphate to maintain maximum grain yields. The current rock-phosphate supplies for superphosphate manufacture are derived from Nauru and Christmas Island in the Pacific Ocean; these supplies are anticipated to last only for the next 10–20 years. The supplies of ‘A’ grade ore (apatite) which can be used directly for superphosphate production are greatly overshadowed by large amounts of lower grade rock phosphate which is high in total phosphate but low in apatite. This material is termed ‘C’ grade rock and, to date, it has found little use in Australian agriculture.

Investigations on condensation phenomena in mercury vapour

1934 ◽  
Vol 30 (2) ◽  
pp. 216-224
Author(s):  
P. C. Ho
Keyword(s):  
Surface Tension ◽  
Chemical Properties ◽  
Mercury Vapour ◽  
Physical And Chemical Properties ◽  
Critical Supersaturation ◽  
Different Temperatures ◽  
Image Position ◽  
Physical And Chemical ◽  
Theoretical Considerations ◽  
And Chemical Properties

Owing to its physical and chemical properties being greatly different from those of any of the liquids which have hitherto been used in the Wilson cloud chamber, mercury has been used in the experiments described in this paper and the condensation phenomena of its vapour at different temperatures observed. Before constructing the apparatus it was considered necessary to get from theoretical considerations some idea about the magnitude of the critical supersaturation for mercury vapour in equilibrium with a drop carrying unit charge. Assuming that J. J. Thomson's formula.where s is the supersaturation of mercury vapour in equilibrium with a drop of mercury of radius a, charge e, density σ and surface tension T, the value of which is assumed here to be independent of the radius of the drop, K the specific inductive capacity of the dielectric surrounding the drop, and R the gas constant for one gramme of weight, all at temperature θ, can be applied to the present problem, this critical supersaturation sm is given by the formula

Rheological and Chemical Properties of Bitumen Modified With Crumb Rubber in the Dry Process

2020 ◽  
Author(s):  
Fayssal Cheriet ◽  
Alan Carter ◽  
Smail Haddadi
Keyword(s):  
Chemical Properties ◽  
Crumb Rubber ◽  
Physical Interaction ◽  
Ftir Analysis ◽  
Digestion Time ◽  
Maximum Increase ◽  
Dry Process ◽  
Different Temperatures ◽  
The Impact ◽  
And Chemical Properties

This research aims to evaluate the performance of the hot mix asphalt modified with crumb rubber by the dry process by studying the temperature’s influence as well as the impact of the digestion time between bitumen and crumb-rubber. The residual bitumen from the drainage test and the non-modified aged bitumen are then subjected to the dynamic shear rheometer (DSR) tests at different frequencies with different temperatures and to Fourier transform infrared spectroscopy (FTIR) analysis. The results show the bitumen and the rubber interaction is directly related to the temperature and the contact time. The maximum increase in rubber mass observed here is about 42% at 195ºC for 120 minutes of contact. The decrease of the light fractions in the bitumen causes a stiffening of the latter as DSR tests show. Lastly, FTIR analysis indicates only a physical interaction.

Structural and Chemical Properties of MBE Grown Niobium Overlayers on (110) Rutile

1996 ◽  
Vol 441 ◽  
Author(s):  
J. Marien ◽  
T. Wagner ◽  
M. Rühle
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Defect Structure ◽  
Chemical Properties ◽  
High Energy ◽  
Initial Growth ◽  
High Energy Electron ◽  
Transmission Electron ◽  
Different Temperatures ◽  
And Chemical Properties

AbstractThin Nb films were grown by MBE in a UHV chamber at two different temperatures (50°C and 950°C) on the (110) surface of TiO2 (rutile).At a growth temperature of 50°C, reflection high energy electron diffraction (RHEED) revealed epitaxial growth of Nb on rutile: (110)[001] TiO2 ¦¦ (100)[001] Nb. In addition, investigations with Auger electron spectroscopy (AES) revealed that a chemical reaction took place between the Nb overlayer and the TiO2 substrate at the initial growth stage. A 2 nm thick reaction layer at the Nb/TiO2 interface has been identified by means of conventional transmission electron microscopy (CTEM) and high-resolution transmission electron microscopy (HRTEM).At a substrate temperature of 950°C, during growth, the Nb film was oxidized completely, and NbO2 grew epitaxially on TiO2. The structure and the chemical composition of the overlayers have been investigated by RHEED, AES, CTEM and HRTEM. Furthermore, it was determined that the reaction of Nb with TiO2 is governed by the defect structure of the TiO2 and the relative oxygen affinities of Nb and TiO2.

The response of a birdwood grass - Townsville lucerne pasture to phosphate fertilizers at Katherine, N.T

1965 ◽  
Vol 5 (17) ◽  
pp. 120 ◽  
Author(s):  
MJT Norman
Keyword(s):  
Dry Matter ◽  
Rock Phosphate ◽  
Maximum Yield ◽  
Experimental Period ◽  
Phosphate Fertilizers ◽  
Virgin Land ◽  
Christmas Island ◽  
Nitrogen Yields ◽  
Forage Yields

In an experiment at Katherine, N.T., the response of birdwood grass-Townsville lucerne (Cenchrus setigerus Vahl and Stylosanthes hurnilis H.B.K.) pasture sown on virgin land to levels of superphosphate and Christmas Island rock phosphate dust and to levels of superphosphate subsequently applied annually for three years was measured. There were no significant interactions between initial and annual applications. Initial applications of 2 and 4 cwt an acre superphosphate both gave higher forage yields of dry matter and nitrogen than 2 and 4 cwt an acre rock phosphate over the experimental period. Phosphorus yield of forage was a function of rate rather than of type of fertilizer. Annual superphosphate applications up to 1 cwt an acre increased the dry matter and nitrogen yields of the grass, but not those of the legume, and increased the phosphorus yield of both. The higher proportion of grass at high superphosphate levels was interpreted as a difference in responsiveness of the two species. A regime of 2 cwt an acre superphosphate initially and 1/2 cwt an acre annually produced 90 per cent of what was considered to be the maximum yield.

Sugarcane Biochar for Agricultural Use Produced in Different Conditions of Pyrolysis

2019 ◽  
pp. 1-8
Author(s):  
Juliany Barbosa de Pinho ◽  
Aloisio Bianchini ◽  
Pedro Silvério Xavier Pereira ◽  
Letycia Cunha Nunes ◽  
Rodrigo Fernandes Daros ◽  
...  
Keyword(s):  
Chemical Properties ◽  
Exchange Capacity ◽  
Raw Material ◽  
Physical And Chemical Properties ◽  
Oxidizing Atmosphere ◽  
Different Temperatures ◽  
Agricultural Use ◽  
Physical And Chemical ◽  
And Chemical Properties

From the pyrolysis process, biochar is a carbon rich and recalcitrant organic material with potential for long term carbon sequestration because of its aromatic structure. However, the physical and chemical properties of the biochar vary due to the diversity of raw material and the conditions of production. The present study aimed to evaluate the biochar from the sugarcane bagasse at different temperatures and under two conditions of pyrolysis. The biochar was produced at two final temperatures 200°C (1 hour); 250°C (1h) and 250°C (2h), with pyrolysis of an oxidizing and non-oxidizing atmosphere for both. PH, cation exchange capacity (CTC), carbon content (C), Nitrogen (N), hydrogen (H), H:C, C:N and ash ratios were evaluated. The contents of C, H, N and the atomic ratios H:C and C:N were higher in Biochar produced in a non-oxidizing atmosphere (BNO). However, the content of ash, pH and CTC were higher in Biochar produced in oxidizing atmospheres (BO). One can conclude the direct influence of the pyrolysis condition.

The response of peanuts to phosphate fertilizers at Katherine, N.T

1965 ◽  
Vol 5 (19) ◽  
pp. 470 ◽  
Author(s):  
LJ Phillips ◽  
MJT Norman
Keyword(s):  
Rock Phosphate ◽  
Early Growth ◽  
Phosphate Fertilizers ◽  
The Third ◽  
Virgin Land ◽  
Christmas Island ◽  
Equal Effectiveness

A four-year experiment on the response of successive crops of peanuts to rates of superphosphate and rock phosphate as initial broadcast applications on virgin land and to rates of annual banded superphosphate was carried out at Katherine, N.T., between 1960 and 1964. By the third year of cropping, with no annual superphosphate, the yield from 4 cwt an acre Nauru or Christmas Island rock phosphate applied initially was slightly greater than that from 4 cwt an acre superphosphate and substantially greater than that from 2 cwt an acre superphosphate. Nauru and Christmas Island rock phosphate were of approximately equal effectiveness. No significant responses were obtained to gypsum in the presence of Christmas Island rock phosphate. Peanuts responded to annual banded applications of superphosphate up to 1 cwt an acre in spite of heavy initial broadcast applications of phosphate. The banded superphosphate was of particular benefit in the establishment and early growth of the crop.

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