SU927782A1 - Raw mixture for preparing clinker - Google Patents

Description

(5) RAW MATERIAL MIXTURES FOR OBTAINING A CLINKER The invention relates to the refractory industry and can be used to obtain a clinker used in the manufacture of magnesia products and nopoujKOB for the repair of linings of metallurgical aggregates. The well-known raw material mixture of HP to produce clinker, including dolomite and highly basic agglomerate, is introduced in an amount of 0 5-15% with a content of iron oxides 46-52 and calcium oxide 20-25. The disadvantage of this mixture is low refractoriness due to the presence of a large amount of calcium ferrite in it. Closest to the invention is a raw mix for producing clinker, including magnesite, dolomite and a mineral additive — chromite ore, with the following ratio of components, weight: magnesite 6585, dolomite 10-20, chromite ore 3-15 ,. The disadvantages of this raw material mixture are high open porosity, clinker and weakness of its refractoriness, low sintering of the resulting clinker when used for repairing the lining of metallurgical aggregates, due to the formation of calcium oxychromite at 12l8 ° C, which at the melting temperature of the metal 1650-1 leads to swelling of the repaired areas as a result of intensive evaporation (from the melt of calcium oxychromite of the lining, as well as the laboriousness of the preparation of the raw calcining mixture, crushing the components of the raw material mixture, their subsequent fine grinding and mixing, wetting the mixture, briquetting it and drying the briquettes. The purpose of the invention is to reduce the open porosity of the clinker and increase its refractoriness. 39 The goal is to ensure that the raw mixture for obtaining clinker, including magnesite, dolomite and mineral additive, as a mineral additive contains siderite ore in the following ratio of components, May.%: Magnesite68-9 Dolomite5 25 Siderite ore 1-7 As a mineral additive is natural or calcined siderite ore is used, which by its material composition is ferrous-magnesium carbonate, mainly consisting of the siderohtlesite mineral and containing, mass fractions,% (per calcined substance): within 50-70 MgO 12-18-, Si On 6, 5. The introduction of natural or calcined siderite ore into the raw mix ensures the open porosity of the resulting clinker is reduced to 3.2-12, L%, while the known clinker has an open porosity of 12.1-19.2. The open porosity of the wedge core obtained from The proposed raw mix is due to the fact that during firing, for example, in a rotary kiln at 600-950C, the magnesian and calcareous carbonates of the mixture are completely decomposed to form magnesium oxides and dispersed and porous carbon particles of low strength. The formation of the structure of periclase-ferric-clinker begins at 1300-1380С with the appearance of a highly ferrous melt, which, interacting with oxides of magnesium and calcium, forms ferritic and. silicate compounds resulting in cementation of dispersed particles, capillary impregnation and compaction due to this coarse-grained porous particles of the raw mix. At higher calcination temperatures (1400–1650 ° C), chemical interaction of primary relatively low-melting compounds 24 occurs with the formation of secondary highly-fire-like refractory compounds by the reaction: a (CaO-MqfO-SiO, j) aCdO-Pe Oj 143b ° C aCdQSi04 WqO f (EVOLUTION: The microstructure of the obtained clinker after cooling is a crystalline intergrowth of periclase and residual lime, cemented by magnesioferrite, silicate CariSi04 and calcium ferrite 2CaO x FerjOg. The presence of silicate and ferritic films around the residual lime prevents hydr The clinker is stored in the clinker with iron-magnesia and lime-magnesia-silicate compounds, which are mineralizers of high-temperature processes in the formation of the structure of clinker, provides the material with sufficiently sintering when used for manufacturing and repairing the lining of metallurgical aggregates. natural or calcined siderite ore in the raw mixture in an amount of more than 7% leads to the formation of significant (Amounts of iron holding the melt, which react with oxides of magnesium and calcium, significantly reduces the refractoriness of the resulting kvinkera and administering siderite ore less than 1 has no effect on sintering raw mix. A raw mix containing 87% magnesite, 10% dolomite is prepared, crushed to lump size 40-0 mm (or mm) and 3% siderite ore calcined at 1050 ° С with a maximum grain size of 15 mm (more than 80 / grain fraction 8- 0 mm) about): flashing in a rotary kiln at 1–50 ° C. Similarly receive clinker from the raw mix with a different ratio of components. The results are shown in the table.

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The table shows that the clinker obtained from the proposed raw mix, and the materials from it have significantly better properties than in the known technical solution,

The advantages of the invention are its simplicity due to the exclusion of fine grinding of components, their mixing, briquetting, drying of briquettes during the preparation of the raw mix and the possibility of fairly easy implementation of the actual production for clinkers and sintered powders. The organization of the production of a wedge-kera from a raw material mixture in the amount of 200 thousand tons per year and its application in the manufacture and repair of linings of metallurgical aggregates makes it possible to achieve an economic effect of at least 5,000 thousand rubles during implementation. per year due to obtaining high quality products, increasing the durability of the linings of metallurgical plants.

and also allows the raw material base of refractory raw materials to be expanded.

Claims (2)

1. Author's certificate of the USSR Vf 321509, cl. From Ot To 33/32, 1972. 2. USSR author's certificate №, cl. From Oif To 35/36, 1970 (prototype).