Pyrite is a sulfide mineral and is widely distributed in nature. Pyrite may transform into pyrrhotite when heated at high temperatures. In order to support processing engineering techniques and industrial applications of pyrite and pyrrhotite, it is necessary to investigate synthetic pyrrhotite, which is formed by heating pyrite in air, based on existing research. In this work, the mineralogical characteristics and stability conditions of synthetic pyrrhotite formed by heating pyrite at elevated temperatures were studied. The possible formation pathway was verified using a solid-phase reaction. X-ray-diffraction results revealed that synthetic pyrrhotite differs from natural pyrrhotite in the paragenetic association of minerals. Natural pyrrhotite and magnetite coexist in the natural pyrrhotite sample. Synthetic pyrrhotite formed by heating pyrite at 700℃ for 1 h has the paragenetic association with hematite and a small amount of pyrite and magnetite. All pyrrhotite samples were monoclinic pyrrhotite-4C (Fe7S8) and exhibit minimal differences in terms of lattice parameters. Synthetic pyrrhotite-4C was stable under 0.5–2 h of heating at 700℃ in air. It had the highest relative content by heating for 1 h. It was eventually transformed into hematite with heating periods exceeding 3 h, as was the case for pyrite and magnetite. In air, synthetic pyrrhotite-4C is mainly formed via two pathways: (1) pyrite → pyrrhotite-4C and (2) pyrite → magnetite → pyrrhotite-4C. Pathway (1) is more favorable than pathway (2). This transformation cannot be achieved by the reaction between hematite and sulfur.

Modern technologies have helped us push the boundaries of geology and begin exploration of other planets. Great strides have been made in the study of Mars, which is slowly yielding up its secrets.

The work presents a two-step method of iron red synthesis based on waste iron(II) sulfate. The synthesis was carried out using purified waste iron sulfate from titanium dioxide production. The study investigated the influence of factors such as temperature, pressure, concentration of solutions and synthesis time on the physicochemical properties of pigments. Obtained pigments were tested by instrumental analytical methods, e.g. X-ray Diffraction or BET surface area analysis. The pigments were analyzed for color, praticles size as well as for oil number. The results of the research showed a change in the physicochemical properties of the obtained pigments depending on the conditions of synthesis. It was shown that increasing the synthesis time in most cases increased the degree of crystallization of hematite in the pigments. High specific surface area, low agglomeration of pigments or low oil absorption are directly related to the crystallinity of the pigments obtained. Laboratory pigments have been found to be different from commercial pigments. The difference in properties speaks in favor of synthesized materials.

Image processing techniques (band rationing, color composite, Principal Component Analyses)

are widely used by many researchers to describe various mines and minerals. The primary aim of

this study is to use remote sensing data to identify iron deposits and gossans located in Kaman,

Kırşehir region in the central part of Anatolia, Turkey. Capability of image processing techniques is

proved to be highly useful to detect iron and gossan zones. Landsat ETM+ was used to create remote

sensing images with the purpose of enhancing iron and gossan detection by applying ArcMap image

processing techniques. The methods used for mapping iron and gossan area are 3/1 band rationing,

3/5 : 1/3 : 5/7 color composite, third PC and PC4 : PC3 : PC2 as RG B which obtained result from

Standard Principal Component Analysis and third PC which obtained result from Developed Selected

Principal Component Analyses (Crosta Technique), respectively. Iron-rich or gossan zones were mapped

through classification technique applied to obtained images. Iron and gossan content maps were

designed as final products. These data were confirmed by field observations. It was observed that iron

rich and gossan zones could be detected through remote sensing techniques to a great extent. This

study shows that remote sensing techniques offer significant advantages to detect iron rich and gossan

zones. It is necessary to confirm the iron deposites and gossan zones that have been detected for the

time being through field observations.

Feldspar is a basic requirement for glass, ceramics, and other industries. The presence of iron in feldspar is one of the challenging aspects of feldspar processing. To improve the quality of feldspar for use in various industries, dry magnetic separation is one of the best techniques for reducing iron in feldspar, especially in arid regions to overcome the common problem of lack of water resources as well as to reduce the operational cost of the enrichment process. Therefore, dry magnetic separation experiments were carried out to remove the iron content from feldspar ore in the Wadi Umm Harjal area in Egypt to meet the specifications required for different industries. The sample was analysed using XRD, XRF, and optical microscopy, which revealed that it is a mixture of potassium feldspar (microcline/orthoclase), albite, and quartz in the presence of hematite mineral serving as the main iron impurities in addition to the free silica content. The effect of parameters on the activity of the dry high magnetic separators was investigated in addition to cleaning the products. The iron oxide reduced from 0.69% in the head sample to 0.08% after dry high-intensity magnetic separation, and the whiteness increased from 82.01% in the head sample to 95.97% in the separated concentrate. The experimental results showed that there is a possibility to obtain feldspar concentrates with low content of Fe2O3 from the area where according to the results, approximately 88.4% of iron was removed from the head sample.