SU1698225A1 - Method of producing high-alumina light-weight refractories - Google Patents

Abstract

This invention relates to a technology for the production of lightweight products that can be used in the linings of high-temperature thermal units with a controlled atmosphere. The purpose of the invention is to reduce the apparent density, thermal conductivity and rejects. Lightweight products are obtained by moistening the expanded polystyrene with a slip from chalk milk and a solution of lignosulfonate, mixing with alumina, casting, drying and roasting, with the initial drying at 20-40 ° C for 5-12 hours, then the temperature of the heat carrier is increased with a speed of 0.1-1.5 & / h up to 60-70 ° C with one evaporation plane or when evaporation across the entire surface of the product, except the support plane, at a speed of 2.0-3.3 ° / h up to 95-105 ° C and speed movement of the coolant 0.5-5.0 m / s, and burned at a rate of temperature rise in the heating zone 40-50 ° C / h to a maximum temperature of 1500 ° C. Physicomechanical indicators are as follows: apparent with a density of 0.42-0.75 g / cm3; thermal conductivity at 325-375 ° C 0.26-0.42 W / mK. 1 tab. cl

Description

The invention relates to the production technology of refractories, in particular, to the technology of lightweight refractory products, which can be used as a refractory lining of high-temperature thermal units with controlled atmosphere, for example, in the lining of furnaces for annealing transformer steel.

The purpose of the invention is to reduce the apparent density, thermal conductivity and scrap.

in the manufacture of high-alumina lightweight plastic with burnable additive from polystyrene.

The method is carried out as follows.

Expanded polystyrene (3-15%) is moistened with a slip consisting of chalk milk and a solution of lignosulfonate (LST) in a two-zone mixer, after which alumina (97-85%) is added and mixing is continued until a homogeneous mass is obtained. The prepared mass is poured into

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metal forms. Drying is performed at a heat carrier temperature of 20-40 ° C for 5-12 hours.

After this preliminary stage of drying, the temperature of the heat carrier is raised at a rate of 0.1-1.5 ° C / h to 60-70 ° C. In the case of evaporation across the entire surface of the product, except for the support plane, after preliminary drying, the heat transfer rate is increased by 2.0-3.3 ° C / h to 95-110 ° C. At the same time maintain the speed of the coolant 0.5-5 m / s.

The dried products are baked at 1500 ° C, while in the preheating zone of the furnace the temperature is raised at a rate of 40-50 ° C / h.

The table shows the parameters of the method and physico-mechanical properties of products.

The form / fa of the invention. A method for the manufacture of high-alumina light-weight refractories, comprising mixing the components, wetting,

casting the billet, drying it and firing, characterized in that, in order to reduce the apparent density, thermal conductivity and scrap in the manufacture of high-alumina lightweight refractory with burnable additive from polystyrene, drying is carried out first at 20-40 ° C for 5-12 hours, and then raise the temperature of the coolant at a rate of 0.1-1.5 ° C / h to 60-70 ° C with the evaporation of moisture through one

the plane of the workpiece or when evaporating across the entire surface of the workpiece at a speed of 2.0-3.3 s / h to 95-105 ° C, and the speed of movement of the coolant 0.5-5 m / s. after which, heating during firing to a maximum temperature of 1500 ° C is carried out at a rate of 40-50 ° C / h.

Manufacturing Method

Initial drying at temperature, ° С

duration h Drying

a) with one evaporation plane:

at the rate of temperature rise of the coolant, s / h

final temperature, ° C or

6) during the evaporation of the entire surface, excluding the support plane at the rate of temperature rise of the heat transfer medium, ° C / h

the speed of its movement, m / s

final temperature

Firing at 1500 C, with the rate of temperature rise in the heating zone, ° C / h

Drying in a tunnel dryer in forms, h

20 8.5

1) 0 12

thirty

five

20 12

0.1 70

1.5 60

о.з

65

0.8 70

2.7 5.0 100

50

3.3

0.5 105

40

2.0 2.8 35

five

3.3 2.8 105

50

12

Claims (1)

Claim A method of manufacturing high alumina ^ lightweight refractories, comprising mixing the components, moistening, casting the workpiece, drying and firing, characterized in that, in order to reduce the apparent density, thermal conductivity and marriage in the manufacture of high alumina lightweight refractory with a burnable polystyrene additive, drying is carried out first at 20-40 ° C for 5-12 hours, and then raise the temperature of the coolant at a speed of 0, T-1.5 ° C / h to 60-70 ° C during evaporation of moisture through one plane of the workpiece or during evaporation through the whole po workpiece surface velocity 2,0-3,3 ° C / h up to 95-105 ° C, wherein the coolant velocity of 0.55 m / s. then heating during firing to a maximum temperature of 1500 ° C is carried out at a speed of 40-50 ° C / h. Method of manufacture and product properties Examples gg ~ t »rr · Famous Production method Initial drying at a temperature, ° C duration, h go 5 40 12 thirty 8.5 20 8.5 40 12 thirty 5 20 12 - Drying a) for one evaporation plane: at a rate of rise of temperature 0.1 1,5 0.8 0.1 1,5 0.S 0.8 final temperature, ° C 60 70 65 70 60 65 70 or 6) during evaporation through the entire surface, excluding the support plane: at the rate of rise of the temperature of the coolant, ° C / h 2.0 3.3 2.7 '2.7 3.3 2.0 3.3 its speed we move NII, m / s 0.5 5,0 2,8 5,0 0.5 2,8 2,8 - final temperature ° C 95 105 100. 100 105 95 105 -. Firing at 1 £ 00 ⁱⁿ C, and the rate of temperature rise in the heating zone, ° C / h 40. fifty - 45 fifty 40 45 fifty Drying in a tunnel dryer in molds, C - - - - - - 12 Firing products at a temperature, ° С - '  " - 1520 Product properties Apparent density, g / cm ¹ 0.75 0.54 0.68 0.67 ¢, 63 0.42 0.50 0.75- Thermal conductivity at Т _Ср 350 + 25 ° С, Βτ / μ · Κ The amount of rejected products, £ 0.42 0.30 0.36 0.35 0.33 0.26 0.38 0.55- 2 3 1,5 5 4 3 2,5 40-45 -4-- 0.90 0.8