49 resultados para Phosphate minerals.

em Deakin Research Online - Australia


Relevância:

20.00% 20.00%

Publicador:

Resumo:

The Mineral and Petroleum Resources Development Act 28 of 2002 has created new categories of rights to "minerals" that may be granted to applicants by the Minister of Minerals and Energy. In this article the nature of these rights will be examined. The legislature has labelled prospecting rights and mining rights to minerals as limited real rights in the MPRD Act. The remaining rights to minerals are not labelled. Provision is made for registration or recording rights in the revived Mining Titles Registration Act 16 of 1967 (as amended). Registered rights are claimed to constitute a limited real right binding against third parties. Discrepancies and contradictions regarding the nature of rights to minerals are created by the two statutes. It is concluded that only upon clarification of the provisions of the two sister statutes, would the nature of rights to minerals be more evident. The proposed amendment of section 5(1) of the MPRD Act would be in line with property doctrine based upon the common law and is to be welcomed.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

This article examines the meaning of "minerals", petroleum, "operations" and activities in relation to such substances to determine the ambit of the application of the Minerals and Petroleum Resources Development Act 28 of 2002, the type of rights necessary for such operations and activities and the ambit of these rights. The examination of the meaning of these concepts takes place with reference to prior definitions in statutes and also from a natural science and geology perspective. An attempt is made to show that the legal definitions do no always correspond with the geological meanings and the meanings on the ground. It is questioned whether in recent legislation why more reliance is not placed on input from geologists in the field.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

Calcium phosphate (Ca-P) coatings were deposited on Ti substrates by a biomimetic method from m-SBF and 10× SBF, respectively. Comparative study of microstructures and bond strengths of the Ca-P coatings deposited from those different SBFs was carried out. Effect of the surface roughness of the substrates on the bond strength of the Ca-P coatings was also studied. Scanning electron microscopy (SEM), X-ray diffractometry (XRD), Fourier transformed infrared spectroscopy (FTIR), inductive coupled plasma spectrometry (ICP) and thermogravimetry (TG) were used to characterize the Ca-P coatings. The bond strengths between the coatings and Ti substrates were measured using an adhesive strength test. Results indicated that the ionic concentrations of the SBFs and the surface roughness of the substrate had a significant influence on the formation, morphology and bond strength of the Ca-P precipitates. The induction period of time to deposit a complete Ca-P layer from the m-SBF is much longer, but the Ca-P coating is denser and has higher bond strength than that formed from the 10× SBF. The Ti with a surface roughness of Ra 0.64 µm and Rz 2.81 µm favoures the formation of a compact Ca-P coating from the m-SBF with the highest bond strength of approximately 15.5 MPa.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

A thorough investigation of conditions required for the precipitation of magnesium ammonium phosphate hexahydrate using magnesia as the source of magnesium was carried out and two computer models were used to make predictions as to optimum conditions for production of suitable crystal size and structure for a successful process. A process was developed and a bench scale model operated for a number of high ammonia wastes. Removal of ammonia was affected to levels of up to 97% with 94% ammonia removal being achievable consistently.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

Mixed rare-earth organophosphates have been investigated as potential corrosion inhibitors for AA2024-T3, and previously have shown synergistic inhibition behavior; however, the mechanism was not identified. In this paper, a key factor contributing to corrosion inhibition of AA2024-T3 with mischmetal diphenyl phosphate [Mm(dpp)3] is the unique stability of Pr(dpp)3 compared to other key rare earths in mischmetal. Although increasing pH causes precipitation of other components, the Pr compound is stable at higher pH. Electrochemically, a synergy is evident when Ce(dpp)3 and Pr(dpp)3 are combined. Raman mapping indicates the Pr(dpp)3 inhibitor leads to a more uniform coverage of the alloy.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

Composite electrolytes of the lithium-ion-conducting ceramic Li1.3Al0.3Ti1.7(PO4)3 and polyetherurethane/lithium triflate polymer electrolyte have been prepared. Microscopy has shown that adhesion between the ceramic and polymer phases is poor, with gaps up to 1 μm at the interface. When dry, the composites are no more conductive than the pure polymer electrolyte. Exposing the samples to the vapour of solvents such as DMF, acetonitrile or water produces a significant increase in conductivity, over and beyond simple plasticization of the polymer. Pretreating the ceramic with a compatibilizing agent improves adhesion at the interface with the polymer, but decreases overall conductivity in the case investigated.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

Choline dihydrogen phosphate ([N1.1.1.2OH]DHP) and 1-butyl-3-methylimidazolium dihydrogen phosphate ([C4mim]DHP) were synthesized as a new class of proton-conducting ionic plastic crystals. Both [N1.1.1.2OH]DHP and [C4mim]DHP showed solid–solid phase transition(s) and showed a final entropy of fusion lower than 20 J K−1 mol−1 which is consistent with Timmerman’s criterion for molecular plastic crystals. The ionic conductivity of [N1.1.1.2OH]DHP was in the range of 10−6 S cm−1–10−3 S cm−1 in the plastic crystalline phase. On the other hand, the ionic conductivity of [C4mim]DHP showed about 10−5 S cm−1 in the plastic crystalline phase. [N1.1.1.2OH]DHP showed one order of magnitude higher ionic conductivity than [C4mim]DHP in the temperature range where the plastic phase is stable.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

Choline dihydrogen phosphate has previously been shown to be a good ionic conductor as well as an excellent host for acid doping, leading to high proton conductivities required for e.g., electrochemical devices including proton membrane fuel cells and sensors. A combination of variable-temperature 1H solid-state NMR and 2D NMR pulse sequences, including 31P and 13C CODEX and 1H BaBa, show that the proton conduction mechanism primarily involves assisted transport via a restricted three-site motion of the phosphate unit around the P–O bond that is hydrogen bonded to the choline and exchange of protons between these anions. In other words, proton transport at ambient temperatures appears to occur most favorably along the crystallographic b axis, from phosphate dimer to dimer. At elevated temperatures exchange between the protons of the hydroxyl group on the choline cation and the hydrogen-bonded dihydrogen phosphate groups also contributes to the structural diffusion of the protons in this solid state conductor.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

Mixtures of the plastic crystal material choline dihydrogen phosphate [Choline][DHP] and phosphoric acid, from 4.5 mol% to 18 mol% H3PO4, were investigated and shown to have significantly higher proton conductivity compared to the pure [Choline][DHP]. This was particularly evident from the electrochemical hydrogen reduction reaction and the proton NMR diffusion measurements, in addition to ionic conductivity measured from the impedance spectroscopy. The ionic conductivity was observed to increase by more than an order of magnitude in phase I (i.e. the highest temperature solid phase in [Choline][DHP]) reaching up to 10−2 S cm−1. The multinuclear NMR spectroscopy data suggest that, at least on the timescale of the NMR measurement, the H+ cations and [DHP] anions are equivalent in both phases. The pulsed field gradient NMR diffusion measurements of the 18 mol% acid sample indicate that all three ions are mobile, however the H+ diffusion coefficient is an order of magnitude higher than for the [Choline] cation or the [DHP] anion, and therefore conduction in these materials is dominated by proton conductivity. The thermal stability, as measured by TGA, is unaffected with increasing acid additions and remains high; i.e. no significant mass loss below 200 °C.