Features of the material composition and possible technologies of pyrite cinders processing

Relevance of research is determined by the need to study for subsequent rational processing of technogenic mineral raw materials – pyrite cinders formed during firing pyritic concentrates for the production of sulfuric acid. Topical issues here are the determination of their chemical and mineral composition, morphology of particles, which predetermine possible technologies of their processing. Purpose of research – study of the material composition of pyrite cinders of the dumps of the Kirovgrad coppersmelting plant, features identification of the composition of different-age dumps. Methods of research. In the selected samples of pyrite cinders, their chemical composition was determined, the morphology of particles was studied by photographing them using the Philips XL-30 electron microscope equipped with an energy dispersive spectrometer (EDS), and possible processing technologies were analyzed. Results. It was found that pyrite cinder of the old dump (no. 1) is characterized by low SO3 contents and low values of losses when firing relative to dump no. 2, which is determined by the oxidation of residual pyrite, as well as CaO and higher Fe2 O3 contents. The study of the morphology of pyrite cinders microparticles showed that they have an irregular shape, globule shape and spherical size from 40 μm to 2 mm. Some known technologies of purple ore processing are considered. Conclusion. The morphology of pyrite cinders particles and their chemical composition were determined as a result of the research. Taking into account the research results and morphostructural characteristics of cinders material, in particular, it is obvious that a number of technologies can be chosen for their complex processing; at the same time this determines further directions of their research, for example, the study of valuable impurity elements in them and their behavior in the process of changing the material of the dumps.

NEMATODE COLONIZATION OF PYRITE CINDER-POLLUTED SOIL

The nematofauna was studied in the early stages of a remediation trial at an industrial site where pyrite cinders had accumulated for 40 years in a large area and were then covered with mineral soil. The cinders were contaminated with several metals and metalloids. The soil of the experimental plots was derived from the mixture of cinders with the covering soil in a 1:1 ratio. Plots were amended with manure and sown with 3 metal resistant plants: Sorghum bicolor L., Helianthus annuus L., and Arundo donax L. Samples were taken : a) at the beginning of the trial on the pyrite cinders and covering soil, separately; b) from the mixture before the application of manure; c) from cultivated plots. Nematode communities were compared by using general composition, trophic structure, biodiversity and ecology indices. Nematofauna and other soil fauna were not detected in the pyrite cinders. Nematodes were recorded in the covering soil and after mixing with the cinders. In these early stages of the remediation process, amending and cropping increased nematode abundance and biodiversity compared to the initial situation of the pyrite cinders. The nematode community structures and all calculated indices showed an increase in the quality of the soil after the remediation process. Our results showed that phytoremediation brought about the repopulation of an extremely compromised area. Moreover, the analysis of nematofauna could be a useful tool for assessing the degree of soil disturbance and soil remediation

Use of Nonferrous Metallurgy Waste: Clayey Portion of the Zircon-Ilmenite Ore Gravity Tailings and Pyrite Cinders in Tile-Making

Studies have shown that using nonferrous metallurgy waste in the ceramic mixture for the making of roof tiles improves the final product quality; one can use the clayey portion of the zircon-ilmenite ore gravity tailings as the clay, pyrite cinders as leaners and sintering intensifier, and wollastonite as an agent to reduce shrinkage and prevent deformation-related buckling. The common method of linear regression was used to study the dependency of the basic physico-mechanical properties of tiles on how much clay from the zircon-ilmenite ore gravity tailings, pyrite cinders, and wollastonite is used in manufacture. The resultant mathematical model takes into account the combined effects these components have on the physico-mechanical properties of tiles; it matches well the experimental data.

Alkalic Leaching and Stabilization of Arsenic from Pyrite Cinders

Introduction: Pyrite cinder is one of the important secondary resources, but typically contains a certain amount of arsenic, which is harmful to metallurgical process. It usually hopes to remove the arsenic prior to recycle the valuable element in the pyrite cinders. Methods & Materials: In this study, the arsenic in the cinders was selectively removed using the alkalic leaching method so as to reduce the loss of ferric and other valuable elements. Results & Discussion: The content of arsenic in pyrite cinders was reduced to 0.08% through the investigation of the factors, including particle size, alkaline concentration, temperature, solid-liquid ratio (S/L) and leaching time. Then, the ferric precipitation method was used to remove the arsenic in the leaching solution. More than 99% of the arsenic can be removed by controlling the pH and the ratio of ferric and arsenic (Fe/As) in ambient temperature, and the arsenic concentration in the solution was reduced to less than 0.5mg/L. Conclusion: It was found that the precipitated arsenic was mainly amorphous based on the analysis of sediment.

Semi-empirical software for the aluminothermic and carbothermic reactions

Understanding the reaction thermochemistry as well as formatting the empirical data about element distribution in gas-metal-slag phases is essential for creating a good model for aluminothermic and carbothermic reaction. In this paper modeling of material and energy balance of these reactions is described with the algorithm. The software, based on this model is basically made for production of high purity ferro alloys through aluminothermic process and then extended for some carbothermic process. Model validation is demonstrated with production of FeTi, FeW, FeB and FeMo in aluminothermic and reduction of mill scale, pyrite cinders and magnetite fines in carbothermic process.

Arsenic Removal from Pyrite Cinders by Oxidizing Roasting with Sodium Hydroxide Addition

A craft of sodium hydroxide roasting-aqueous leaching process is investigated for the treatment of a high arsenic pyrite cinders, a common by-product in vitriol industry. The pyrite cinders, containing 58.27% Fe, and 0.98% As, was conducted for the craft. The results demonstrated that iron concentrate with 58.87% Fe, 0.13% As and 87.40% of arsenic removal percentage was obtained under the optimal conditions (a roasting temperature of 1000°C, a roasting duration of 120 min and a mass ratio of sodium hydroxide to pyrite cinders of 8%).This craft can be used to utilize pyrite cinders and produce qualified concentrate as iron-bearing feed for steel industry, which will help to solve the pollution of pyrite cinders and extend raw material sourcing for Chinese steel industry.