Chair “Metallurgical Technologies and Equipment”, Nizhniy Novgorod State Technical University named after R. E. Alekseev, Nizhniy Novgorod, Russia:

V. A. Korovin, Assistant Professor of a Chair, e-mail: mto@nntu.nnov.ru

I. O. Leushin, Professor, Head of a Chair

T. D. Kurilina, Senior Lecturer of a Chair

O. V. Tokarnikova, Engineer of a Chair

V. A. Ulyanov was the participant in this work.

Nowadays, many plants, producing non-ferrous alloy foundries, have a problem of obtaining of high-quality products (especially using low-quality charge). Using domestic scrap and waste as charge inevitably leads to contamination by various impurities and increasing of gas saturation alloys (reduction of castings' quality and production of goods, which do not conform to the needs of consumers). This problem can be solved by modifying-refined processing of the melt. In this regard, calcium, barium, strontium and sulfate carbonates are of particular interest. They can be used for implementation of classical adsorption-flotation gear during refining of melt-schim modifying effect. This article presents the thermodynamic calculations of possible chemical and thermal reactions of carbonate melt copper alloy (brass) at secondary treatment temperatures. Thermodynamic calculations, characterizing dissociation and slagging (using carbonates) are carried out, which suggests that in the temperature range of 1200–1500 K, the opportunity dissociation of sodium carbonate has the maximum probability. Processes of thermal dissociation of barium and strontium carbonates are also carried out at copper alloy melting temperature, while thermal dissociation of calcium carbonate is complicated and takes place at higher temperatures. This article presents the results of pilot studies on determination of efficiency of brass melt carbonate processing in ladle at JSC “Casting and Mechanical Plant” (Semenov, Nizhniy Novgorod region). There are given the testing results of mechanical properties of samples after brass melt carbonate processing, indicating positive influence. Results of these studies demonstrate the feasibility and efficiency of refining and modifying of brass melt by carbonate mixture, accompanied by increasing of mechanical properties and improvement of castings' microstructure.

1. Chaykina N. V., Chaykin V. A., Zadrutskiy S. P., Nemenyuk B. M., Rozum V. A. Rafiniruyushchaya smes s modifitsiruyushchim effektom na osnove karbonatov (Refining mixture with modifying effect on the basis of carbonates). Zagotovitelnye proizvodstva v mashinostroenii = Blank Production. 2012. No. 1. pp. 3–7. 

2. Korovin V. A., Ulyanov V. A., Tokarnikova O. V., Sluzov P. A. Osobennosti ispolzovaniya rafiniruyushche-modifitsiruyushchego flyusa pri lite latuney (Peculiarities of use of refining-modifying flux during brass casting). Sbornik trudov XI sezda liteyshchikov Rossii (Collection of proceedings of XI meeting of Russian casters). Ekaterinburg, 2013. pp. 112–115.