Lithium,a preliminary survey of its mineral occurrence in flint clay and related rock types in the United States

Maximum concentrations of lithium found in samples of flint clay and associated rocks of Pennsylvanian age in different States, in parts per million (ppm), are: Missouri, 5100; Pennsylvania-Maryland, 2100; Kentucky, 890; Ohio, 660; Alabama, 750; and Illinois, 160. Lithium-bearing kaolin deposits are distributed in the Coastal Plain province from New Jersey to Texas, and one occurs in Idaho; maximum lithium concentrations in samples from these deposits range from 64 to 180 ppm. The maximum concentration found in the Arkansas bauxite region is 460 ppm and that in flint clay in Colorado is 370 ppm. Samples from areas other than Pennsylvania, Maryland, Kentucky and Missouri are relatively few in number, represent mostly commercially valuable clays, and represent only a part of the refractory clay deposits in the United States. Data are not available on the clays associated with these deposits that may be unusable because they contain too much lithium as well as other deleterious elements. In both Pennsylvania and Missouri, lithium contents vary regionally between districts and locally between deposits.In samples containing more than 2000 ppm lithium, the lithium occurs in a dioctahedral chlorite mineral very similar to cookeite, which previously has not been recognized in sedimentary clays. The associated clays consist chiefly of well-crystallized kaolinite. The dioctahedral chlorite, however, seems to be most abundant where diaspore and boehmite occur along with the kaolinite. Barium, chromium, copper, phosphorus and strontium are present in some samples in amounts of several hundred pans per million or more, and may contribute to the failure of some clays to perform satisfactorily in firing tests.Lithium-rich clays could serve as a significant lithium resource in the very distant future. Clays that contain as much as 1% lithium may be common enough in Missouri or in Pennsylvania to be produced as a by-product to help support benefication costs for refractory clays. Sufficient amounts of lithium-rich clay may be found in deposits that have been explored, found unsatisfactory for normal refractory uses, and not developed. The lithium-rich clay in some deposits presently being worked may be worth stockpiling for eventual use.     

Present situation and prospects for lignite in the Polish power-generation industry

In Poland, lignite is mined in open pits and four deep mines, producing totally about 60–65 million tons a year. Extracted lignite constitutes a fuel for power plants with a total installed capacity of 8833 MW, which generate some 35% of electric energy nationally. This energy is cheaper compared with that from other sources. Poland, with its huge deposits of lignite, is placed in a privileged position, for apart from at present mined deposits, which constitute only about 15% of workable reserves, some abundant areas exist, where mining working can be started. At present, the mined deposits allow us to maintain a current yearly output for the forthcoming 15 years, whereas through the subsequent 30 years, it will decline. In order to maintain supplies of lignite, which is a significant fuel in Poland, it is necessary to fully utilize deposits in the existing areas, and develop new zones where lignite occurs.     

微波加热对褐煤干燥及成浆特性的影响

针对外水分和内水分含量都很高的褐煤,利用微波700 W加热10 min使其干燥,可有效地改善其成浆性能,使最大成浆浓度由原煤的45.67%增加到51.65%。利用六种薄层物料干燥数学模型对褐煤干燥过程进行计算,发现Page模型可很好地描述褐煤的微波干燥过程。褐煤脱水能耗随着微波功率增大而降低,当用大反应容器、大装样量时的微波能耗比小反应容器、小装样量时要低。经微波干燥后的褐煤若放置于空气中,发现微波改性使煤样二次吸水的负作用受到明显抑制。     

Combustion Characteristics of 24 Lignite Samples

Abstract

In this study, the combustion characteristics such as thermogravimetric analysis (TGA) and differential thermogravimetric analysis (DTGA), burning profile, ignition temperature, and peak temperature were analyzed for 24 lignite samples from different areas of Turkey. The samples were heated up to 900°C at a constant rate of 10°C/min in a 5 mL/min flow of dry air. The burning profiles of the samples studied, combined with proximate, sulfur analysis and calorimetry results, contribute to a clearer identification of lignite samples' structure and a better understanding of the coalification process. The lignite samples have been tested with particle size of 0–0.05 mm. Ignition temperatures of the samples have been determined from their burning profiles.     

Pore structure development in Xilingol lignite under microwave irradiation

The pore structure of Xilingol lignite irradiated by microwave was investigated to determine drying time, microwave power level, and mineral composition. Pore structure was also determined using N₂ adsorption/desorption as well as scanning electric microscopy. The results show that as microwave power increases from 400 W to 800 W, and irradiation time increases from 4 to 16 min, the specific surface area of lignite samples increases, average pore diameter and total pore volume decreases, and the percentage of mesopores increases. The pore volumes, average pore diameters, and special surface area in the center of the lignite sample were greater than those in the outer layers, while the percentage of mesopores decreased slightly. The cluster structure of the lignite samples is simpler and the surface neater, while flat and fibrous structures remain the same. Evolution mechanisms for pore structures during microwave drying were similar, and include structural collapse caused by shrinkage forces resulting from the removal of moisture, the opening and crosslinking of blind and closed pores, and the thermal decomposition of organic macromolecular structures under high temperatures.     

Concentration of Major and Trace Elements in the Miocene Lignite from the Çanakkale-Çan Coalfield

Abstract

This study focuses on major and trace element concentrations of three lignite samples, of which two are from the working lignite seam and one from a feed coal to Çan thermal power plant. The Çanakkale-Çan lignite deposit is currently being mined by open-cast mining methods despite its high sulfur content. The production lignites are mainly consumed by Çan fluidized-bed thermal power plant with 2 × 160 MW capacity and less domestic heating and industrial factories around Çan. Major oxide compositions of the coal ash samples imply that the more abundant oxides are SiO₂ and Al₂O₃ and less CaO and Fe₂O₃. Trace element concentrations in the samples on whole-coal basis show that three samples analyzed were enriched in V, and also concentrations of B, Sc, Sn, Th, Tl, and U in one sample that exceed the range values of most world coals.     

Dielectric properties of Australia lignite at radio frequency

Dielectric properties (dielectric constant and loss factor) of Australia lignite were determined using an impedance analyzer and other instruments over the moisture contents of 8–48%, temperature of 25–100°C, and frequency of 1–50 MHz. Both dielectric constant and loss factor of lignite samples increased monotonically with the increase of moisture content at all temperatures and frequencies. Dielectric constant increased with the increase of frequency, and loss factor changed quadratically: first decreased and then increased. Dielectric constant increased with the increase of temperature at low moisture contents (8–28%), but it decreased at high moisture contents (38–48%), and loss factor increased with the increase of temperature at all moisture contents. The penetration depth of radio frequency energy of Australia lignite was obtained through the equation. It decreased with the increase of moisture content, temperature, and frequency.     

Petrographic Characteristics of the Kardia Lignites (Core KT6A-3), Ptolemais Basin (Greece)

The aim of this study is to provide useful coal-petrographic data, which will further help the characterization, exploitation, and utilization of the Kardia lignite deposit and also initially to access the depositional conditions mainly in terms of water table level and subsidence rate of the fen substrate. Ash contents, as well as the C, H, N, O, and S were determined in nine lignite samples from core KT6A-3. The ash contents (750°C) of the studied lignite seams range among 14–37% (on dry basis). Contents of C, H, N, and O have values between 34–52%, 2.5–4.2%, 0.8–2%, and 21–30.6%, respectively. Sulfur does not exceed 1.2%. Huminite group dominates with values between 84–99 vol%, mmf. All samples display a distinct prevalence in detrohuminite (up to 82 vol%) with attrinite being most abundant. Liptinite and inertinite macerals have low contents, which do not exceed 8% and 12%, respectively. The Kardia lignites are medium to very low-grade coals. They formed in fens under limnotelmatic regime and originated from herbaceous vegetation. During peat deposition, conditions were well moist, intense reducing, and favored increased bacterial activity. The ratio of plant growth and peat accumulation versus rise of water table due to the subsidence rate was not well balanced. The petrographical composition of the Kardia lignites is related either to a long residence time of the organic matter in the acrotelm or to an herbaceous vegetation origin.     

Towards the improvement of thermal efficiency in lignite‐fired power generation: Concerning the utilization of Polish lignite deposits in state‐of‐the‐art IGCC technology

Integrated coal Gasification Combined Cycle (IGCC) is the most advanced technology for coal‐fired power generation. The two‐stage entrained flow gasification process allows for the use of a wide range of coal, as long as the gasification temperature is above the ash melting point of a used fuel. In this gasification technology, lignite, which often has a low ash melting point, can be preferably utilized. However, ash fluidity is also another importance, because the behaviour of molten slag can diminish a stable ash discharge from a gasifier. As the eligibility of coal ash properties is a considerable factor, water physically and chemically kept in lignite (30 – 60% in mass) attributes to deteriorating gasification efficiency, because it causes significant heat loss and increasing oxygen consumption. Developing a thermal evaporative lignite drying method will be a necessary attempt to apply lignite to the coal gasification process. For those preceded objectives, coal and ash properties and drying characteristics of several grades of Polish lignite, extracted from Belchatow and Turow deposits, have been experimentally investigated in a preliminary study evaluating the applicability and consideration for its utilization in state‐of‐the‐art clean coal technology, IGCC. This paper particularly discusses the eligibility of Polish lignite from the perspective of the fusibility and fluidity of ash melts and the fundamental drying kinetics of lignite in superheated steam in the light of water removal. The viscosity of ash melts is measured at high temperature up to 1700 °C. In the drying tests, the significant influence of structural issues, because of the provenance and origin of lignite on the drying characteristics, was found by applying the method of sensitivity analysis of physical propensity. This paper concludes that the investigated Polish lignite has characteristics favourable for utilization in IGCC technology, once the precautions related to its high moisture have been carefully addressed. Copyright © 2016 John Wiley & Sons, Ltd.     

Newer mining technology and plans for increased use of lignite in India

The total inferred reserves of lignite in India are about 3680 million t, out of which the Neyveli Lignite Field in Tamil Nadu State, South India, accounts for 3300 million t. This field is mined by the mechanized opencast method, using bucket wheel excavator-belt conveyor-spreader continuous mining technology. The lignite is mainly used for power generation. The present level of lignite production is 6.5 million t/yr. The mining of lignite at Neyveli is faced with major problems like tackling hard, abrasive Cuddalore sandstone overburden, high pressure aquifers below lignite seams and high monsoonic storm water. These problems have been successfully overcome in stages, and the mine has achieved very high capacity utilization during 1984–1985. Up to March 1985, about 83.8 million t of lignite have been mined from this field. Taking into consideration the future demand for power in the energy-starved southern region, Neyveli Lignite Corporation (NLC) plans to develop a second mine producing 10.5 million t/yr of lignite, and is also considering opening new mines to increase lignite output to 32 million t/yr by the year 2000. Measures are also being taken to maintain the environmental quality in the mining and industrial complex.     

A study of spontaneous combustion characteristics of a turkish lignite: particle size, moisture of coal, humidity of air

This study evaluated the spontaneous combustion characteristics of Askale lignite from Turkey. The effect of the gas flow rate, the moisture of the piles of coal, the humidity of the air and particle size on the spontaneous combustion characteristics of coal samples were examined using Crossing Point Methods adapted to our laboratories conditions. The amounts of three predominant oxygen functional groups (carboxyl, hydroxyl and carbonyl) in untreated and moist coal samples were also determined with wet chemical methods. The amounts of oxygen functional groups in moist coal samples do not differ significantly from that of untreated coal. The liability of spontaneous combustion of this lignite was increased with decreasing particle size, increasing moisture content of the coal and decreasing humidity of the air.     

Solubility and molecular composition of organic species in low-rank coals during sequential thermal dissolution in cyclohexane and methanol

In this study, six low-rank coals (LRCs) including two lignite samples and four subbituminous coals were sequentially dissolved in cyclohexane and methanol. The yields of cyclohexane-soluble portions (SPs) from the lignite are slightly lower than those from the subbituminous coals, while the yields of methanol SPs showed a linear correlation with the oxygen content and O/C ratio. The concentrations of n-alkanes and polycyclic aromatic hydrocarbons in the SPs of subbituminous coals are higher than those of the lignite, and the concentrations of phenols in the SPs are possibly associated with the content of aryl ether bonds in the LRCs.     

Petrographic composition of the ex-situ lignite gasification residues

The article presents the results of the petrographic analysis of the lignite from Turów deposit and the residues formed during its ex-situ gasification. The analysis used seven spot samples, representing different transformation areas, collected from the residues. The obtained results, compared with the lignite before the gasification, have shown that changes in the petrographic composition correspond to the temperature distribution during the process. The highest amounts of gasified particles, represented by inertoid-type chars, were observed in samples collected from areas where the temperature exceeded 600°C. The unchanged lignite macerals dominated in samples from areas where the temperature was below 200°C.     

Liquefaction/Solubilization of Low-Rank Turkish Coals by White-Rot Fungus (Phanerochaete chrysosporium)

Microbial coal liquefaction/solubilization of three low-rank Turkish coals (Bursa-Kestelek, Kütahya-Seyitömer and Mu?la-Yata?an lignite) was attempted by using a white-rot fungus (Phanerochaete chrysosporium DSM No. 6909); chemical compositions of the products were investigated. The lignite samples were oxidized by nitric acid under moderate conditions and then oxidized samples were placed on the agar medium of Phanerochaete chrysosporium. FTIR spectra of raw lignites, oxidized lignites and liquid products were recorded, and the acetone-soluble fractions of these samples were identified by GC-MS technique. Results show that the fungus affects the nitro and carboxyl/carbonyl groups in oxidized lignite sample, the liquid products obtained by microbial effects are the mixture of water-soluble compounds, and show limited organic solubility.     

The economics of indigenous energy use: The case of northern Ireland lignite

The paper sets out an economic framework within which to judge the potential economic benefits of using newly discovered indigenous fuel reserves. It illustrates the method with extensive reference to the newly discovered deposits of lignite in Northern Ireland. For a long time, the lack of indigenous fuel supplies, together with some unfortunate decisions on fuel use, resulted in Northern Ireland having the highest energy costs of any region in the United Kingdom. Although not the bonanza it was originally thought to be, lignite offers the possibility of a secure source of fuel to power at least part of the local electricity supply system, the smallest isolated electricity supply system in western Europe.     

Intermediate technologies towards low-carbon economy. The Greek zeolite CCS outlook into the EU commitments

Technological premises for a successful economical path toward low carbon economy are described. It is attempted to relate fossil fuels (lignite) combustion with the requirements for sustainable energy production in Greece proposing economic, feasible and environmentally friendly methods for minimization of the CO₂ problem using innovative techniques for separation, carbon capture and storage (CCS) of this greenhouse gas. CCS constitutes an intermediate perspective to a low carbon energy production. Inexpensive and efficient methods of CCS can be achieved by new physicochemical methodologies enhancing the adsorption driven carbon dioxide capture in zeolite voids or in depleted lignite matrices, eventually by exploitation existing natural Greek deposits. The large scale application of a recently developed method leading to a high CO₂-over-N₂ selectivity and adsorption capacity NaKA Zeolite is examined.     

Bacterial desulphurization of low-rank coal: A case study of Eocene Lignite of Western Rajasthan,India

High sulfur lignite samples collected from Giral mine was subjected to desulfurization using bacteria Burkholderia sp. GR 8–02 isolated from native lignite. A removal of 50.69% of total Sulfur (S_t) has been observed. The reduction in hydrogen and ash content was found up to 2.92% and 14.78%, respectively. In addition, relative carbon (up to 12.81%) and nitrogen (up to 34.52%) has also been increased. An increase in the relative concentration of volatile matter and fixed carbon (up to 19.47% & 3.29%) has been detected. In addition, the desulfurization of high sulfur lignite with Burkholderia sp. GR 8–02 increased the calorific value from 5.24% to 20.74%.     

Palaeoenvironmental Conditions of the Mavropigi Lignites,Ptolemais Basin,Greece: A Petrological Study

The aim of this study is to interpret the palaeoenvironmental conditions established during the formation of several lignite seams at the Mavropigi deposit, Ptolemais, Greece (corehole MAK-48). In nine representative lignite samples, ash contents, as well as the contents of the elements C, H, N, O, and S were determined. Polished block sections from the same samples were examined under the microscope. The ash contents (750°C) of the studied lignite seams range between 10–29% (on dry basis). The contents of C, H, N, and O display values between 36–55%, 2.4–4.6%, 0.7–2%, and 21–37.5%, respectively, while S contents do not exceed 1.4%. Huminite is the prevailing maceral group (87–95%). All the samples, except No. 35, display a distinct prevalence in detrohuminite maceral subgroup (up to 69 vol%, mmf). Liptinite and inertinite maceral groups show low contents, which do not exceed 9% and 7%, respectively. The Mavropigi lignites are medium to low grade coals and can be regarded as peat to lignite in terms of thermal maturity. The studied lignite seams formed in fens, possibly from herbaceous plants under limnotelmatic regime. During peat deposition, conditions were very moist and intense reducing with increased bacterial activity. The ratio of plant growth and peat accumulation versus rise of water table due to the subsidence rate was not well balanced. As a result, the petrographical composition of the Mavropigi lignites is related either to a long residence time of the organic matter in the acrotelm or to a herbaceous vegetation origin.     

Effect of Various Experimental Parameters on the Swelling and Supercritical Extraction Properties of Lignite

Abstract

The original lignite sample, the samples swollen in dimethylsulfoxide (DMSO), dimethylformamide (DMF), pyridine, tetrahydrofuran (THF), acetone, ethylenediamine (EDA), N-methyl-2-pyrrolidone (NMP), tetrabutylammonium hydroxide (TBAH), the samples impregnated by ZnCl₂ as catalyst and the samples both swollen in the solvents and impregnated by ZnCl₂ were subjected to the supercritical toluene extraction and the effects of temperature, pressure, pre-swelling procedure, hydrogen donor solvent (tetralin), and catalyst on the extract yields were investigated.