The research was aimed at examining the impact of the petrographic composition of coal from the Janina mine on the gasification process and petrographic composition of the resulting char. The coal was subjected to fluidized bed gasification at a temperature below 1000°C in oxygen and CO2 atmosphere. The rank of coal is borderline subbituminous to bituminous coal. The petrographic composition is as follows: macerals from the vitrinite (61.0% vol.); liptinite (4.8% vol.) and inertinite groups (29.0% vol.). The petrofactor in coal from the Janina deposit is 6.9. The high content of macerals of the inertinite group, which can be considered inert during the gasification, naturally affects the process. The content of non-reactive macerals is around 27% vol. The petrographic analysis of char was carried out based on the classification of International Committee for Coal and Organic Petrology.

Both inertoid (34.7% vol.) and crassinetwork (25.1% vol.) have a dominant share in chars resulting from the above-mentioned process. In addition, the examined char contained 3.1% vol. of mineroids and 4.3% vol. of fusinoids and solids. The calculated aromaticity factor increases from 0.75 in coal to 0.98 in char. The carbon conversion is 30.3%. Approximately 40% vol. of the low porosity components in the residues after the gasification process indicate a low degree of carbon conversion. The ash content in coal amounted to 13.8% and increased to 24.10% in char. Based on the petrographic composition of the starting coal and the degree of conversion of macerals in the char, it can be stated that the coal from the Janina deposit is moderately suitable for the gasification process.

The aim of the paper is the petrographic characterization of coal from the Wieczorek mine and the residues after its gasification. The coal was subjected to gasification in a fluidized bed reactor at a temperature of about 900°C and in an atmosphere of oxygen and CO2. The petrographic, proximate, and ultimate analysis of coal and char was performed. The petrographic composition of bituminous coal is dominated by macerals of the vitrinite group (55% by volume); macerals of inertinite and liptinite groups account for 23% and 16.0%, respectively. In the examined char, the dominant component is inertoid (41% vol.). Mixed dense and mixed porous account for 10.9% and 13.5% vol., respectively. In addition, the examined char also contained unreacted particles such as fusinoids, solids (11.3% vol.), and mineroids (5.1% vol.). The char contains around 65% vol. of low porosity components, which indicates a low degree of carbon conversion and is associated with a low gasification temperature. The char was burned and the resulting bottom and fly ashes were subjected to petrographic analysis. Their composition was compared with the composition of ashes from the combustion of bituminous coal from the Wieczorek mine. Bottom ashes resulting from the combustion of bituminous coal and char did not differ significantly in the petrographic composition. The dominant component was mineroid, which accounted for over 80% vol. When it comes to fly ash, a larger amount of particles with high porosity is observed in fly ash from bituminous coal combustion.

The Bogdanka coal mine, the only currently operating mine in the Lublin Coal Basin (LCB),

extracts coal from the Upper Carboniferous formations of the LCB. The average sulfur content in

the No. 385/2 seam is 0.98%, while in the case of the No. 391 seam it is slightly higher and amounts

to 1.15%. The iron sulfides (pyrite and marcasite) in bituminous coal seams form macroscopically

visible massive, vein, and dispersed forms. A microscopic examination has confirmed their complex

structure. Massive forms contain euhedral crystals and framboids. The sulfide aggregations are often

associated with a halo of dispersed veins and framboids. Pyrite and marcasite often fill the fusinite

cells. Framboids are highly variable when it comes to their size and the degree of compaction within

the carbonaceous matter. Their large aggregations form polyframboids. The cracks are often filled

with crystalline accumulations of iron sulfides (octaedric crystals). The Wavelenth Dispersive Spectrometry

(WDS) microanalysis allowed the chemical composition of sulfides in coal samples from the

examined depoists to be analyzed. It has been shown that they are dominated by iron sulfides FeS2 –

pyrite and marcasite. The examined sulfides contain small admixtures of Pb, Hg, Zn, Cu, Ag, Sb, Co,

Ni, As, and Cd. When it comes to the examined admixtures, the highest concentration of up to 0.24%,

is observed for As. In addition, small amounts of galena, siderite, and barite have also been found in

the examined coal samples. The amounts of the critical elements in the examined samples do not allow

for their economically justified exploitation. Higher concentrations of these elements can be found in

the ashes resulting from the combustion process.

The article presents the analysis of the correlation between the self-ignition parameters and the ultimate and proximate analysis, as well as the petrographic properties of Polish lignite, sub-bituminous coal, bituminous coal and anthracite. The following coal properties were determined: the moisture, ash content, volatile matter and sulfur content, gross calorific value, net calorific value, C, O, N and H contents, total porosity, ash oxide composition, rates of spontaneous combustion in 237°C and 190°C, and activation energy. During the petrographic analysis, maceral composition and random reflectance were determined. To determine the linear correlation between the self-ignition parameters and the analyzed coal properties, the Pearson correlation coefficient was calculated. The results show that there is no strong linear correlation between the lignite tendency to self-ignition and its petrographic properties. However, a strong negative correlation between the rate of spontaneous combustion and moisture and volatile matter content was observed. In the case of bituminous coal, strong correlations between self-combustion parameters and various coal properties were confirmed. The most noteworthy are the correlations between self-ignition parameters and the maceral composition, that is, between the content of macerals of the inertinite group in coal and content of macerals of the huminite/vitrinite group. The obtained results suggest that the spontaneous combustion tendency of coal increases with the increasing content of semifusinite and liptinite.

Municipal waste is a global issue and they are generated in all countries around the world. Both in the European Union and the United States, a common method of non-recyclable waste utilization is thermal incineration with energy recovery. As a result of this treatment, residual waste like bottom ash, air pollution control residues and fly ashes are generated. This research shows that residues from waste incineration can be a potential source of critical raw materials. The analysis of the available literature prove that the residues of municipal waste incinerators contain most of the elements important for the US and EU economies. Material flow analysis has shown that each year, the content of elemental copper in residues may be 29,000 Mg (USA) and 51,000 Mg (EU), and the amount of rare earth elements in residues exceeds their mining in the EU. In the case of other elements, their content may exceed their extraction by even over 300%. The recovery of elements is difficult due to their encapsulation in the aggregate matrix. The heterogeneous nature of residues and the many interactions between different components and incineration techniques can make the process of recovery complicated. Recovery plants should process as much of the residues as possible to make their recovery profitable. However, policy makers from the EU and the US are introducing new legal regulations to increase the availability of critical raw materials. In the EU, new regulations are planned that will require at least 15% of the annual consumption of critical raw materials to come from recycling. Therefore, innovative technologies for recovering critical raw materials from waste have a chance to receive subsidies for research and development.