Synthesis of zeolite-A using kaolin samples from Darazo, Bauchi state and Ajebo, Ogun state in Nigeria

Kaolin samples from Ajebo and Darazo in Nigeria were characterized and used to produce zeolite - A crystals. The thermal analysis indicates that both samples under gode-hydroxylation from 450oC to about 700oC and are converted to metakaolin with a weight lo ss of about 11.39 and 10.43% for the Ajebo and Darazo samples respectively. Characteristic OH, Al-OH, Si-OH and Si-O-Albands were confirmed in both samples with Infra-red spectroscopy studies. The X - ray diffraction patterns clearly show the presence of the characteristic peaks (12.35 and 24.88o ) of kaolinite with little quartz impurities. X - ray diffraction measurements (2Ɵ peaks at 7 – 18o and 21 – 35o ) and scanning electron micro graphs clearly show that zeolite - A crystals are produced. The microstructures of kaolin, metakaolin and zeolite - A crystals reveal the presence of platy crystals, amorphous spherical aggregates and cubic - shaped crystals with some amorphous gel respectively . The results show that both Ajebo and Darazo kaolin are suitable for zeolite - A synthesis. Keywords: Kaolin, Metakaolin, Thermal analysis, X - ray Diffraction, Zeolite -

Beneficiation of Barite Ore from Azara in Nassarawa State, Nigeria, using Froth Flotation

Barite ore from Azara in Nassarawa State has been beneficiated using Jigging and Froth Flotation techniques by varying the pH of the solution. The chemical analysis indicates the presence of major elements Ba, S, O and minor elements like Ti, V, Al and Si which confirms that it is barite while the particle size analysis showed that the average particle size is ≈ 150 µm with a 1,167 cm2/g specific surface area. The X-ray diffraction analysis of both the as-mined ore and beneficiated samples indicate increased intensity in the later. The jigging result shows that 51% of the feed is the underflow while 46.7% is the overflow. The measured specific gravity as a function of pH show that values between 3.78 and 4.23 are obtained. The elemental composition of the Barite after beneficiation shows that in addition to high contents of BaO and SO3, the amount of SiO2 present is still very high. The sample with a pH value of 7 gave the highest specific-gravity value of 4.23 while that with pH of 3 gave the lowest specific-gravity value of 3.78. The implication is that the barite sample with pH of 7 is acceptable for oil and gas applications while more work is needed for samples with other pH values

Beneficiation of Barite Ore from Azara in Nassarawa State, Nigeria, using Froth Flotation

Barite ore from Azara in Nassarawa State has been beneficiated using Jigging and Froth Flotation techniques by varying the pH of the solution. The chemical analysis indicates the presence of major elements Ba, S, O and minor elements like Ti, V, Al and Si which confirms that it is barite while the particle size analysis showed that the average particle size is ≈ 150 µm with a 1,167 cm2/g specific surface area. The X-ray diffraction analysis of both the as-mined ore and beneficiated samples indicate increased intensity in the later. The jigging result shows that 51% of the feed is the underflow while 46.7% is the overflow. The measured specific gravity as a function of pH show that values between 3.78 and 4.23 are obtained. The elemental composition of the Barite after beneficiation shows that in addition to high contents of BaO and SO3, the amount of SiO2 present is still very high. The sample with a pH value of 7 gave the highest specific-gravity value of 4.23 while that with pH of 3 gave the lowest specific-gravity value of 3.78. The implication is that the barite sample with pH of 7 is acceptable for oil and gas applications while more work is needed for samples with other pH values

Influence of microstructure on symmetry determination of piezoceramics

The origin of the complex reflection splitting in potassium sodium niobate doped with lithium and manganese was investigated using temperature-dependent high-resolution X-ray and neutron diffraction as well as electron probe microanalysis and scanning electron microscopy. Two structural models were developed from the diffraction data. A single-phase monoclinic Pm model is known from the literature and is able to reproduce the diffraction patterns perfectly. However, a model with phase coexistence of two classical orthorhombic Amm2 phases can also reproduce the diffraction data with equal accuracy. Scanning electron microscopy in combination with electron probe microanalysis revealed segregation of the A-site substituents potassium and sodium. This favours the model with phase coexistence and confirms the need for comprehensive analyses with complementary methods to cover a broad range of length scales as well as to assess both average and local structure