RU2282603C2 - Refractory gunite-mass - Google Patents

Abstract

FIELD: refractory materials.

SUBSTANCE: invention proposes the refractory gunite-mass designated mainly for consumable fettling intermediate ladle for machine of continuous casting blanks. Refractory gunite-mass comprises components in the following ratio, wt.-%: organic fiber, 0.1-1.0; inorganic fiber, 0.1-0.4; polymeric binding agent with an ester-base plasticizer, 2.0-5.0; periclase-containing filling agent, the balance. Refractory gunite-mass can comprise also 0.5-4.0 wt.-% of sodium tripolyphosphate and 0.2-2.0 wt.-% of phenolformaldehyde resin. Invention provides enhancing porosity, reducing heat conductivity, enhancing mechanical strength and adhesion in applying, improving exploitation properties and possibility for applying the thickened layer of gunite-mass.

EFFECT: improved and valuable properties of mass.

2 cl, 1 tbl

Description

The invention relates to the refractory industry, mainly to refractory shotcrete masses for consumable lining of the CCM intermediate ladle.

Known refractory shotcrete masses with periclase-containing aggregate and a binder, for example, inventions according to as USSR No. 1616881 C 04 V 35/04, 1990 [1]; RF patents No. 2155733 C 04 V 35/043, 2000 [2], No. 2159219 C 04 V 35/043, 2000 [3]; Patents DE 10202964 C 08 K 5/10, C 04 B 35/622, 2003 [4]; EP 0758632 C 04 B 35/66, 1997 [5].

According to the set of common essential features, the shotcrete mass according to patent EP 0758632, C 04 B 35/66, 1997 [5] is the closest to the patented one. It contains, wt.%: Periclase-containing aggregate - base, organic fiber 0.01-0.5, organic polymer binder 2-10 in the form of a mixture of pitch and phenol-formaldehyde resin.

The disadvantages of this mass are: mass creep when applying a shotcrete layer with a thickness of more than 30 mm, sintering with a lining in the process of service, increased thermal conductivity. These shortcomings do not provide effective thermal protection of the working lining of the bucket in the service and good durability of the shotcrete coating.

The objective of the present invention is to provide a durable, resistant shotcrete mass, not slipping when applied with a layer of up to 65 mm and good thermal insulation properties. The technical result consists in increasing porosity, reducing thermal conductivity, increasing mechanical strength and adhesion during application, the absence of strong sintering of the shotcrete mass with the surface of the reinforcing layer due to less coking, easier removal of scrap without destroying the integrity of the reinforcing lining, the possibility of applying a thickened expendable working spray gun -layer due to the retention of fibers by a binder and the creation of an internal reinforcing frame.

To achieve this, according to claim 1 of the invention, the refractory mass further comprises an inorganic fiber and an organic fiber in the following ratio of components, wt.%: Organic fiber 0.1-1.0; inorganic fiber 0.1-0.4; said binder 2.0-5.0; periclase-containing aggregate - the rest.

The essence of the invention lies in the fact that organic fiber provides uniform removal of moisture from the shotcrete coating during drying, eliminating the formation of microcracks and peeling when the bucket is heated, and gives the shotcrete coating thermal insulation properties due to the formation of a finely porous structure after burning out the fibers. Inorganic fiber prevents slipping of the shotcrete coating by creating an internal reinforcing cage, allows to increase the thickness of the coating up to 65 mm and reduces the shrinkage of the shotcrete coating during drying. The fine dispersion of the inorganic fiber and the loose surface structure favor the mechanical fastening of the fibers in the polymer chains of the binder during coagulation of its particles, resulting in a strong reinforcing frame. To enhance this effect, the sizing of the inorganic fiber should be compatible with the molecules of the polymer binder and not create an intermolecular separation phase. Such a sizing agent may be, for example, starch or paraffin.

The polymer binder with an ester-based plasticizer used in shotcrete is a synthesized polymer soluble in water. When the binder solution is dehydrated during drying of the shotcrete coating, the polymer molecules merge and form polymer films. These films at the material interface serve as glue, providing increased adhesion of the shotcrete to the surface of the working lining of the bucket.

With the introduction of a shotcrete mass of less than 0.1 wt.% Organic fiber, the porosity and thermal conductivity are not achieved. The introduction of organic fiber of more than 1.0 wt.% Leads to clogging of the mouthpiece of the shotcrete machine and a significant decrease in the mechanical strength of the shotcrete coating at a temperature of 800-1000 ° C due to increased porosity.

When less than 0.1 wt.% Of inorganic fiber is introduced into the shotcrete mass, a reinforcing frame is not formed and partial coating creep occurs with a thick layer. The introduction of inorganic fibers of more than 0.5 wt.% Causes the mass to hang in the hopper of the shotcrete machine and to form in the service an excessive amount of fusible compounds, which entails increased penetration of slag and metal into the shotcrete coating.

Cellulose and / or wood fibers can be used as organic fiber, and basalt and / or kaolin and / or glass fiber as inorganic fiber.

As periclase-containing aggregate, for example, fused or sintered periclase, as well as calcined dunite or mixtures thereof, can be used.

In accordance with claim 2, the shotcrete further comprises sodium tripolyphosphate and phenol-formaldehyde resin in the following ratio, wt.%:

organic fiber 0.1-1.0 inorganic fiber 0.1-0.4 specified binder 2.0-5.0 sodium tripolyphosphate 0.5-4.0 phenol formaldehyde resin 0.2-2.0 periclase-containing aggregate rest

An additional introduction to the shotcrete mass together with a polymer binder, organic and inorganic fiber of sodium tripolyphosphate and phenol-formaldehyde resin allows to reduce water consumption, enhance adhesion and significantly increase the mechanical strength of the shotcrete coating in the low and high temperature range. As the phenol-formaldehyde resin, powdered resole and novolac resins, for example, bakelite resin or phenol-formaldehyde binder of the TFP type, can be used.

The introduction into the composition of the shotcrete mass of sodium tripolyphosphate less than 0.5 wt.% And phenol-formaldehyde resin less than 0.2 wt.% Is not enough to significantly increase the mechanical strength, and their introduction of more than 4.0 and 2.0 wt.% Respectively increases the alkali content in bulk and affects the environmental safety of the use of shotcrete.

Refractory shotcrete mass is obtained as follows.

Materials used: sintered periclase with a MgO content of 97.5 wt.%, Cellulose organic fiber - cotton wool (TU 5768-001-24365670-2001), inorganic fiber - chopped basalt thread (TU 5952-034-00204949-95), burnt dunite (TU 14-8-169-75), sodium tripolyphosphate (TU 48-0328-25-94), phenol-formaldehyde resin (TU 2257-241-00203447-97), powdered bakelite resin, polymer binder LITHOPIX ST5 with plasticizer based ester (carboxylic acid) in the form of a water-soluble polymer powder (dispersed polyacrylate) company ZSCHIMMER & SCHWARZ GMBH & CO (DE), a thinner l (for the prototype) - plasticizer S-3 (TU 2481-001-51831493-00).

To obtain a refractory mass, these components were used in the amounts given in the claims. The components are dosed, loaded into the mixer, mixed in a dry state, then the mixture is unloaded and packaged in soft containers with a polyethylene liner. Before shotcreting, water is added to the mixture in an amount of 20-25 wt.% And the mass is mixed.

The compositions and properties of the refractory gunite mass are given in the table.

As can be seen from the table, the patented mass has a greater porosity, significantly lower thermal conductivity and higher mechanical strength. The resistance of the created shotcrete mass in industrial trials was eight heats.

The determination of the properties of the refractory mass was carried out:

- compressive strength according to GOST 4071.1-94;

- thermal conductivity according to GOST 12170-85.

Information sources

1. A.S. USSR No. 1616881 C 04 V 35/04, 1990.

2. RF patent No. 2155733 C 04 V 35/043, 2000.

3. RF patent No. 2159219 C 04 V 35/043, 2000.

4. Patent DE 10202964 C 08 K 5/10, C 04 V 35/622, 2003.

Claims (2)

1. Refractory shotcrete mass, including periclase-containing aggregate, organic fiber and organic binder, characterized in that it additionally contains inorganic fiber, and as an organic binder, a polymeric binder with an ester-based plasticizer in the following ratio, wt.%: Organic fiber 0.1-1.0 Inorganic fiber 0.1-0.4 Specified Binder 2.0-5.0 Periclase-containing aggregate Rest 2. Refractory gunite mass according to claim 1, characterized in that it further comprises sodium tripolyphosphate and phenol-formaldehyde resin, in the following ratio, wt.%: Organic fiber 0.1-1.0 Inorganic fiber 0.1-0.4 Specified Binder 2.0-5.0 Sodium Tripolyphosphate 0.5-4.0 Phenol formaldehyde resin 0.2-2.0 Periclase-containing aggregate Rest