SU1025696A1 - Method for making expanded clay - Google Patents

Description

9

The invention relates to the production of building materials, c. part tfocTH aggregates used in aggressive environments and at elevated temperatures.

A known method of manufacturing a lightweight aggregate, such as expanded clay, is made by dusting clay granules with a powder of secondary remelting of aluminum alloys 1.

The disadvantages of this method are insufficient refractoriness and alkali resistance of the aggregate, since the refractory and highly resistant crystalline phases (mullite and a small amount of spinel) are formed in the surface layer of the granule, while the glassy phase predominates in the central part of the granule.

The closest to the proposed technical essence and the achieved effect is the method of making claydite, including the grinding of clay granules by the waste of divinyl production for synthetic rubber

However, expanded clay gravel obtained by this method has a low alkali resistance due to the high content of chromium oxide in the powder, as well as low refractoriness of the expanded clay granules due to the presence of nitrate acid cache in the powder, causing the appearance of fusible eutectic.

The purpose of the invention is to increase the refractoriness and alkali resistance of the aggregate.

This goal is achieved by the fact that, according to the method for the manufacture of expanded clay, including dusting clay granules with alumina-containing powder, the granules are powdered with powder of ferrotitanium production.

The powder of dump donkeys of ferrotitanium production has the following, chemical composition, wt%: SiOj 0.081, 6; A & iO, 69.0-75.0- T1Og 18.318, 7; ReaOz 2.7-3.5, - FeO, 5; CaO 1-1,2 i MgO 0.4-2.2,

Waste slags from the production of ferrotitanium are brownish in color. According to the mineralogical composition, spacs contain corundum, aluminotitanate and ilmenite. Possessing a complex mineral composition, waste dumps of ferrotitanium production by dusting clay granules in the area of expanded clay cause the following physical and chemical processes.

Hit the surface of the granules and fill the defect; surfaces, slag particles are embedded and intensively absorbed by the melt, the formation of which is due to

melting of low-melting minerals that make up the clay raw material. The refractory components of waste slag, such as corundum with a melting point of 2 04 O-2O 5 ° C and aluminotitanate with a melting point of 1890 ° C, are subjected to liquid-phase sintering both between themselves and with the remaining, on the surface of the mineral, granule particles,

As a result of the ongoing process on the surface of the granule, a compacted, - consisting of refractory crystalline compounds, free from defects layer, giving the whole granule high refractory properties - is formed.

In addition, more low-melting compounds of waste slags, which include the crystalline phase, represented by the ReTuI ilmenite with a melting point below, and the amorphous phase at a temperature of swelling (128Q13, 00 ° C) form a melt enriched with titanium and iron ions. which, penetrating deep into the granules, is absorbed by the evolution of clay minerals and low-melting eutectics by melt. Being an active crystallization catalyst, Ti ions contribute to the formation in the glassy phase of the central part of the granules of refractory crystals, in particular, aluminotitanate, and heikilite. Due to the increase in the total content of the crystalline phase, the alkali resistance and refractoriness of the central part of the granule increase.

Along with an increase in the total content of the crystalline phase, the introduction of ions into the amorphous phase leads to a significant rearrangement and compaction of the framework of the glassy phase.

The method is carried out in the following.

Raw clay granules are formed from clay raw materials with the following technological methods: they are dried and then burned during firing; The furnace is baked with simultaneous feeding of previously prepared powder in the amount of 2–4% by weight of the raw granules. The firing is carried out at the optimum temperature of expansion. Cooling is carried out by known methods.

PRI me R. From clay raw materials, smssh of the Evskoye and Buzulukskoye deposits, by plastic method, form granules d h 10 mm. The formed granules are dried in a dry cupboard at. After drying, a part of the granules are calcined in a laboratory rotary kiln with the introduction of an impregnator in the amount of 2.5% by weight of the raw granules. Dust slag from ferrotitanium production milled on balls to mill with a specific surface of 1940 cmVr is used as an impregnator. The crushed slags have the following chemical composition, May. %: SiO l, 2i 73.4 ;; TiOi 18.5: Fe, 0 2.8 | FeQ I, 3; CaO 1 MgO 1.7. . Another part of the molded grana is pre-powdered with a waste of divinyl production for synthetic rubber. The impurity consumption is 2.5% by weight of the raw granules. The precious granules are dried in a drying cabinet at 105 ° C and burned in a laboratory spin with a kiln. ; .. :. After firing and cooling, the apparent density of the granules is determined :, the splitting strength, And they are subjected to refractoriness and alkali resistance. The refractoriness of the aggregate is determined in accordance with the requirements of GOST 20955-45 Aggregates for heat-resistant concrete. Determination of the alkali resistance of clay pellets of new granules includes boiling them in alkali e solution (35% H 2N NaOH / solution, washing with hot distilled water until neutral, and drying at constant mass. According to the known and proposed method, they are shown in Table 1. From the data in the table, it follows that the proposed method allows for improved haydite, since it has improved quality compared to the claydite obtained by the prototype method. fire resistance and alkali resistance.

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Claims (1)

METHOD FOR PRODUCING KERAMZIT, including dusting clay granules with an alumina-containing powder, such as in order to increase the refractoriness and alkali resistance of expanded clay, the granules are dusted with the powder of dump slag for the production of ferrotitanium.