SU952811A1 - Method for making refractory products for cleaning molten metal - Google Patents

Description

since it was necessary to melt the glass from the initial components, it was necessary to grind the resulting glass before ..- to walk the glass through a 30.0 mesh sieve (0.05 mm). The products obtained in a known manner, when using a refractory filler with a predominant grain fraction of 1.0 mm, have the following physical and mechanical properties. The limit of mechanical compressive strength, MPa 3.5 Volume weight, g / cm 1.94 Porosity is open,% 25.80 The coefficient of air permeability of one product (in height), m 3 cm 1.3-3.5 m 2-h. Mm aq. Art. Pore prevailing, µm .200 The pore scatter of the optimum value on a single product, µm ± 50 Water resistance,% 96 Acid resistance,% 94.8 Alkali resistance% 90.4 and not destroyed in molten metal, in particular aluminum. The aim of the invention is to increase the mechanical strength of products and ensure uniform distribution of pores in the volume of products. The goal is achieved according to the method of manufacturing refractory products for cleaning molten metal, including mixing a fractionated refractory filler, a binder and a low-melting component, molding, drying and roasting, as a low-melting component, a technical calcium borate is used in an amount of 516 wt.%, which is mixed with a refractory filler, le in that the mixture is introduced into a binder and the resulting mixture was stirred for 5-10 min 3 7 wt.% of fine alumina. Moreover, the technical calcium borate with a particle size of 0.060, 5 mm, and alumina with a particle size of 0.001-0.5 mm, are used. In addition, magnesium phosphate or aluminum chromophosphate or soluble sodium or potassium silicate is used as a binder. When mixing dry powders of fine powder (calcium borate and coarse refractory filler, parts are uniformly redistributed and then onto their wetted fluid-bonding surface a thin layer adheres alumina powder to the mass. Due to uniform distribution of additives between the filler particles The porosity is formed uniformly over the entire volume of the material. The uniform distribution of the material pores is characterized by a change in the permeability coefficient along the height of the product and deviations from With this sequence of mixing the raw mix, the cohesion of the melt formed directly during the firing of the product increases with the filler grains, because low-melting compounds of boron and calcium, being not pre-transformed into glass, actively interact not only with aluminum oxide, but and with a large grain of the filler. As a result, the adhesion of the additives to the filler grains melted in the roasting increases, and, consequently, the mechanical strength of the product increases. The use of soluble silicates of sodium or potassium, aluminum chromium phosphate, magnesium phosphate in the amount of 3-7% by weight of the inorganic filler allows the products to be calcined without backfilling. The proposed method makes products of any shapes and configurations. Example 1. Refractory filler: brown electrocorundum of fraction -1 + 0.80 Mivi is mixed with calcium technical borate powder with a particle size of 0.06-0.2 mm (the resulting dry mixture is moistened with soluble sodium silicate and then mixed with finely dispersed corundum material (particle size 0.06 mm) containing AljOj in the amount of 92%. Composition by weight,%: fractionated electrocorundum 90, calcium borate 5, fine dispersed corundum 5, soluble sodium silicate 4 (in excess of 100%). From the semi-dry mass molded slabs with a size of 330x330x20 mm, which are dried at 100 ° C for 1 h and burned at 1050 ° C with an exposure at this temperature for 2 hours. The temperature rise rate was 100 ° C / h. Example 2. Corundum refractory filler (waste of high-alumina brick) with particle size of 3 + 0.5 mm is mixed with calcium borate, particle size of which 0.2-0.3 mm, then moistened with soluble potassium silicate and stirred for 10 minutes with alumina micropowder. Of the composition,%: 1 corundum filler 80 (Fr. -3 + 0.5 mm), technical calcium borate 16, soluble potassium silicate, with a density of 1.34 in excess of 100% and alumina 4 molded plates with dimensions of 330x330x20 mm, which are dried

at 100 ° C and burned without backfilling in the furnaces at 1050 ° C at a rate of temperature rise to the optimum 100 ° C / h and a shutter speed of 2 hours.

Example 3. White electrofused corundum with a particle size of -1.5+ +1.0 mm is mixed with calcium technical borate (particle size O, 30 0, 40 mm), moistened with an aluminum-chromophosphate binding agent and stirred for 8 min. corundum material (particle size less than 0.5 mm). From the mass of the composition,%: filler 92, calcium borate 5, fine corundum 3, aluminum chromium phosphate bond 3 in excess of 1 & 0%, molded tubes of size 115x85x430. M, which are dried for 4 hours at 30.0 s and calcined without backfilling at 135СР С with an exposure at this temperature of 5 hours. The rate of temperature rise was.

Example4. Mulite refractory filler with a particle size of -0.8 + 0.5 mm in an amount of 85% is mixed with 8% calcium borate (particle size 0.4-0.5 mm), then moistened with a magical phosphate binder and stirred for 5 min. 7% alumina (particle size 0.5 mm). Magnesium phosphate is used in an amount of 7% in excess of 100%. From the resulting mixture, molded slabs size ZOOHZOOH x 35 mm, which is dried for 6 hours, then burned without backfilling with aging at

This temperature is 3 hours. The rate of temperature rise to the optimum 1-00 ° C / h.

The properties of the obtained products and known tabulated.

When comparing the properties of the products manufactured by the proposed method and the known one, as a result of using the invention, the mechanical strength is increased by 3 times, the variation in pore size is reduced from ± 50 to ± 20 and the variation in pipe height of the air permeability coefficient is 10 to

+0.20

what

  h - mm aq. Art.

five

indicates an increase in the uniformity of the distribution of pores in the material.

Experimental testing of products obtained by the proposed method

0 is carried out in molten aluminum alloys at 700-750 ° C. The increased strength of the proposed filters allows them to be used at high hydrostatic metal pressures,

5 which has a positive effect on the technological process, increasing the filter capacity and its life until clogging. Homogeneous porosity and small pore scatter prevent particle leakage.

0 contamination through the filter, which provides a significant increase in the purity of the filtered metal.

Claims (2)

1. A method of manufacturing refractory products for cleaning molten metal, comprising mixing 60 fractional refractory filler, a binder and a low-melting component, molding, drying and roasting, and with the aim of increasing mechanical strength. 65 to ensure uniform distribution of pores in the volume of the product, technical calcium borate in the amount of 5-16 wt.% is used as a low-melting component, which is mixed with a refractory filler, after which the binder is added to the mixture and the resulting mass is mixed for 5 -10 minutes 3-7 wt.% Fine aluminum oxide, 79528118 2. Method POP.1, distinguished by alumochromophosphate or soluble sisch and with the use of sodium or potassium silicate. Calcium borate with an hour size. Sources of information particles 0.06-0.5 mm, and the oxide hshyumini sprintoe taken into account during the examination particle size of 0.001-0.5 mm.1. U.S. Patent 1,299,740, Cl, 106-63, 3, The method according to claim 1, distinguished from 1961. with the fact that as a binder is 2. US Patent No. 3524548, Cl. 210-153, using 9t magnesium phosphate or 1970..