Kristalizacija i struktura lijevane A 390.0 legure iz taline zagrijane na povišenim temperaturama

The paper presents the research on the influence of melt overheating temperature on crystallization parameters and primary structure of cast AlSi17Cu5Mg (A390.0) alloy overheated to temperature: 820 °C, 880 °C, 940 °C and 1 000 °C. It was found that the degree of overheating influences the change of microstructure significantly and morphologies of primary silicon of the castings from Al-Si alloys. Research has shown that the overheating of the liquid metal bath is one of the methods of finding more applications of hypereutectic Al-Si system alloys without the addition of modifiers.Članak daje istraživanje utjecaja taline na parametre kristalizacije i primarne strukture lijevane legure AlSi17Cu5Mg (A 390.0) zagrijane na povišenim temperaturama: 820 °C, 880 °C, 940 °C i 1 000 °C. Utvrđeno je da stupanj utjecaja pregrijavanja mjenja značajnije mikrostrukturu silikata lijevanih Al-Si legura. Istraživanje ukazuje da pregrijavanje tekućeg metala je jedna od metoda pronalaženja veće primjene hipereutektičkih Al-Si legura bez dodataka modifikatora

A study on the process of fine-grained plumbiferous material agglomeration

In the paper, results of a study on the agglomeration process of fine-grained plumbiferous materials, belonging to basic resources for lead recovery, are presented. For the agglomeration tests, a laboratory drum granulator and a balling disc were utilized. The obtained granules were tested for compression strength with the use of a so-called Michaelis testing device as well as for drop strength, determined per the standards. The results allowed for evaluating the effects of the composition of the blend of materials subjected to agglomeration on the quality of obtained granules

Modifications of the chemical composition and microstructure of flash smelting copper slags in the process of their reduction

Blister copper smelting in a flash smelting furnace results in generation of slag that contains high amounts of copper, iron and lead. Most commonly, this material is subjected to reduction with coke in an electrical furnace. In the present paper, results of investigations on reduction of slag with another reducer, i.e. anthracite dust, are discussed. Each experimental slag was analysed for its microstructure, chemical composition and phase composition. Based on the results, a decopperisation level of the study material was estimated. It was shown that anthracite dust might be considered as an alternative for currently used reducers

Wastes from the coal-enrichment process as alternative reducers for lead smelting from lead-acid accmulator scrap

In the paper, results of the study on a possible utilization of coal-enrichment wastes as alternative reducers for lead smelting from acid-lead accumulator scrap are presented. For the experiments, the following alternative carboniferous reducers were selected: coal slurry, anthracite dust and coal soot. The investigations included both laboratoryscale experiments and semi-industrial tests in a rotary furnace. The findings allowed for a review of the effects of a sample type (loose material or material post a preliminary agglomeration process), loaded into the furnace, on a final process yield

Wettability in the liquid Cu-Ag alloy – fireproof material – gas phase system

In the present paper, results of wettability studies on the liquid metal – fireproof material – gas phase system using copper and Cu-Ag alloys as well as typical fireproof materials, i.e. aluminium oxide, magnesium oxide and graphite, are presented. Contact angle measurements were conducted at 1 373–1 573 K by means of a high-temperature microscope coupled with a camera and a computer equipped with a program for recording and analysing images. For the measurements, the sessile drop method was used

Reduction of copper slag with the use of carbon granulates

The investigation results on the reduction of slag from flash smelting furnace and the use of carbon granulates obtained from fine-grained waste materials of both the coal enrichment and coking processes have been presented in the paper. The investigation results on the reduction of slag from flash furnace and the use of carbon granulates obtained from fine-grained waste materials of both the coal enrichment and coking processes have been presented in the paper

Reduction of Lead Oxide by Fine-Grained Carbonaceous Materials

As part of the presented work, tests were carried out to check the possibility of replacing of conventional reducers used in the lead pyrometallurgical processes by cheaper, but equally effective substitutes. For research of lead oxide reduction, the following fine-grained carbonaceous materials were used, ie anthracite dust and coal flotation concentrate, as well as traditional used coke breeze for comparison. The obtained test results indicate a similar ability to reduce the lead oxide of all studied carbonaceous materials