An assessment of the calcination characteristics of the mfamosing limestone for quality commercial lime production.

High quality lime is an essential raw material for many industries (such as steel, chemical, sugar etc) all over the world. In Nigeria most of the demand for this chemical product is met through importation. The Cretaceous Albian carbonate of the Calabar Flank - the Mfamosing limestone is hereby assessed for production of quality lime. The limestone is fine-grained, fossiliferous and composed dominantly of algal boundstone and lenses of oolitic wackestone and packstone. X-ray fluorescence (XRF) and X-ray diffraction (XRD) were employed in its chemical and mineralogical investigations. The suitability of the limestone for commercial lime production depends on its chemical purity (66.69% CaCO3) and calcination process. Consequently the limestone was calcined through a range of temperature (9500C, 10000C, 10500C and 11000C) for varied retention times (60, 90, 120 minutes) and the burning characteristics were determined. Thus technological tests such as loss on ignition of lime, decrepitation, mechanical strength, and reactivity with water (slaking test) were carried out. The 10500C/90 minutes calcine yielded best quality product - a compact, soft burned, porous and highly reactive lime (>400C rise) desired by lime manufacturers. The Mfamosing limestone is highly recommended for commercial lime production.KEY WORDS: Lime, calcinations, soft-burned, purity, commercia

Alternative Fuels for Internal Combustion Engines

Researchers have studied on alternative fuels that can be used with gasoline and diesel fuels. Alternative fuels such as hydrogen, acetylene, natural gas, ethanol and biofuels also uses in internal combustion engines. Hydrogen in the gas phase is about 14 times lighter than the air. Moreover, it is the cleanest fuel in the world. On the other hand because of its high ignition limit (4–75%), low ignition energy, needs special design to use as pure hydrogen in internal combustion engines. It is proved that hydrogen improves the combustion, emissions and performance, when is added as 20% to fuels. Natural gas is generally consisting of methane (85–96%) and it can be used in both petrol and diesel engines. Ethanol can be used as pure fuel or mixed with different fuels in internal combustion engines. In this section, the effects of natural gas, hydrogen, natural gas + hydrogen (HCNG), ethanol, ethanol + gasoline, ethanol + hydrogen, acetylene, acetylene + gasoline mixtures on engine performance and emissions have been examined

Sustainable soil stabilisation with ground granulated blast-furnace slag activated by olivine and sodium hydroxide

Ground granulated blast-furnace slag (GGBS), activated with olivine (Mg2SiO4) and sodium hydroxide (NaOH), was used to stabilise a clayey soil. Mechanical and microstructural properties of the stabilised soil were assessed through uniaxial compression strength (UCS) tests, X-ray diffraction, scanning electron microscopy and energy-dispersive X-ray spectroscopy (EDS), after curing periods of 7, 18 and 90 days. The UCS of the GGBS-treated soil (without activation with NaOH), even at the highest slag dosage (G20S), after 90 days, showed only a slight increase (142 kPa) relatively to the original soil. When olivine was added to the GGBS-treated mixture (O20G20S), the UCS increased to 444 kPa, after 90 days. However, when NaOH was used as an activator, the UCS of the olivine–GGBS-treated soil (NO20G20S) increased to more than 6000 kPa, after 90 days. This significant strength increase was attributed to the higher reaction degree provided by the NaOH, which enabled a more effective exploitation (dissolution) of the Ca and Mg present in the slag and olivine, respectively, forming a mixture of C–S–H and M–S–H gels

Feasibility of Using Nanosilanes in a New Hybrid Stabilised Soil Solution in Rural and Low-Volume Roads

The application of new materials for soil stabilisation is a growing field of study in recent years. In this work, the effect of two types of silica-based nanomaterials combined with binders (quicklime and cement) are studied to stabilise soils and form structural layers for rural and low volume roads. The physical and chemical properties of the materials have been determined, as well as the mechanical behaviour of the stabilised soil. Three hybrid stabilised soil sections have been designed using a multilayer elastic model, executed at full scale and measuring the evolution of their properties in the medium to short term. The results show that the application of silica-based nanomaterials and two types of binders on the tread layers provide high structural stability and good behaviour of the sections

Hydration and carbonation reactions of calcium oxide by weathering: Kinetics and changes in the nanostructure

The weathering reactions of hydration and carbonation of nanostructured calcium oxide with atmospheric moisture and carbon dioxide have been characterized. This work is the first-to-date combined kinetic and nanostructural research on CaO oriented to two key processes for different systems, i.e. hardening of construction materials and carbon mineral sequestration. The evolution of the precipitated crystalline phases was monitored by X-ray diffraction and thermogravimetry, along with structural characterization by nitrogen physisorption, electron microscopy and small-angle scattering. Complete hydration of the samples was always found prior to the onset of carbon sequestration, which depended on the nanostructure of the samples. Hence, carbonation started after 300 h of weathering for samples with a specific surface area of 40 m2/g, whereas carbonation of the samples with 20 m2/g occurred after 550 h. Full carbonation from atmospheric CO2 (100% efficiency) was obtained in all cases. This combined research was completed by developing an empirical description of the weathering reactions in terms of a two-process Random Pore Model. Finally, this work aimed to determine the role of the nanostructure of samples based on industrial wastes as one of the most important factors for developing efficient carbon sequestration technologies.España Mineco MAT2013-42934-

Applied Geology of Industrial Limestone and Dolomite

Indiana Geological Survey Bulletin 46The title of this report as first proposed was "What a Consulting Geologist Should Know About Industrial Limestone" because this effort was born of a request from the Indiana-Kentucky Geological Society, Inc., for a refresher course in the economic geology of limestone. The present title was adopted, however, because the completed report is understandable to anyone with some formal or informal geologic training and an interest in the applied geology of industrial limestones. Many of Indiana's mineral producers have developed a keen understanding of the geology associated with the particular deposit that they work, but because of a lack of training, they do not know how geology can be used in a broader sense to explore and exploit limestone deposits. We believe that this report will help answer some of the questions frequently asked by both the consulting geologist and the mineral producer. Consulting geologists and mineral producers certainly need to know something about industrial limestone. The total tonnage of carbonate rocks mined or consumed in the United States in 1968 was about 603 million tons and the total value about 857 million dollars (U.S. Bureau of Mines, Minerals Yearbook, 1968). To meet the need for this basic building block of our society, the deposits now being sought must be larger, purer, and more strategically situated than ever before. Once a new quarry meant the investment of a few tens of thousands of dollars. Now it is likely to mean a million or more. The producer cannot afford to make this investment in an inadequate deposit. He needs the help of a geologist, and he needs to be able to evaluate geologic information properly. To reach as broad an audience as possible, we have used a minimum of technical terms. According to custom, industrial limestone of limestone is here synonymous with limestone and dolomite unless the contest indicates otherwise. The chemical composition of limestone is important in many uses, and limestone and dolomite are often described in terms of their carbonate context. These terms are arbitrary and depend partly on the context, both in terms of use and availability of high-grade limestone. As used in this report, high-calcium limestone is limestone composed of 95 percent CaCO3. Ultra-high calcium limestone is more than 97 percent CaCO3, high-purity carbonate rock is more than 95 percent combined CaCO3 and MgCO3, and high-purity dolomite is more than 42 percent MgCO3. (Theoretically, pure dolomite would contain 45.7 percent MgCO3.)Indiana Department of Natural Resource