RU2265780C2 - Method for heat plant lining repair with heat-resistant concrete - Google Patents

Abstract

FIELD: building materials, particularly heat-resistant concrete production.

SUBSTANCE: method involves preparing lining surface before special mix application on the surface; treating the lining surface with 50-70% orthophosphoric acid or acid phosphate solution; applying fine heat-resistant concrete mix; hardening it; impregnating the heat-resistant concrete mix layer with 50-70% orthophosphoric acid or acid phosphate solution; heat-treating the obtained layer at the first setting of heat plant in operation and bringing thereof to operational mode.

EFFECT: increased operational reliability, simplified technological process and reduced liming repair costs.

1 ex, 1 tbl

Description

The invention relates to the building materials industry, namely the manufacture of heat-resistant concrete, and can be used to repair the lining of thermal units.

A known method of repairing the lining by applying to the hot surface of the refractory a thermite mass of silicon powder, manganese concentrate, iron ore concentrate and chamotte, in which sodium chloride and water are previously introduced to a visco-plastic state / Pat. RF №2187484, IPC ⁷ С 04 В 35/65. Hot repair method for lining coke ovens and termite mass for hot repair Gamma-2 KS / MP Utkin, AV Tivin, Yu.V. Belov - No. 2001106535/03; Stated March 14, 2001; Publ. 08/20/2002 / [1].

The reasons that impede the achievement of the technical result indicated below when using the known method include the complexity and high cost of repairs due to the need to use it only when the thermal units are hot.

The closest method of the same purpose to the claimed invention in terms of features is a method of impregnating concrete with polymers in order to improve the physicomechanical properties of concrete products, such as strength, abrasion, frost resistance, water resistance. For this, finished concrete or reinforced concrete products are subjected to special processing, which includes drying of products, evacuation, impregnation with a special composition and polymerization / Concrete technology / Yu.M. Bazhenov. - Moscow: DIA, 2002. - 500 p. / [2], adopted as a prototype. The reasons that impede the achievement of the following technical result when using the known method adopted for the prototype include:

1) the complexity of the process;

2) the dependence of the final properties of the material on the properties of the concrete being processed.

The technical result of the invention is to increase the operational properties of the resulting coating, simplifying the process and reducing the cost of repairing the lining.

The technical result is achieved by the fact that in the known method of repairing the lining of thermal units with heat-resistant concrete, including preparing the surface of the lining with subsequent application of a special composition, the peculiarity is that before applying the latter, the surface of the lining is treated with a 50-70% solution of phosphoric acid or acid phosphates, then apply a fine-grained heat-resistant concrete mixture, after hardening of which the obtained layer is impregnated with a 50-70% solution of phosphoric acid or acid phosphates in a subsequent heat treatment at the first start and output to the thermal unit mode.

During drying and heat treatment, phosphate solutions interact with the constituent oxides and minerals of the hardened heat-resistant concrete with the formation of stable refractory metal phosphates. The scientific approach to the use of liquid phosphates in the repair of linings is based on their chemical activity to interact with many inorganic compounds (oxides, silicates, aluminates, etc.). Phosphates by the condition of formation are inorganic polymers. The main structural element of phosphates is the group PO ₄ ^3- , which has one oxygen atom on the surface, connected by a double bond to the central phosphorus atom. This structure gives the surface of heat-resistant phosphate-bonded concrete non-wettable by various melts. Therefore, phosphoric acid and ligaments based on it are preferably used as a solution for the formation of a layer between the old brick and new concrete linings.

Example:

From the proposed compositions of fine-grained dense fireclay concrete, prototypes were prepared on two types of binders: Series I — on Portland cement for repairing the lining of the preparatory drum of a rotary expanded clay kiln; Series II - on liquid glass for repair of the lining of the kiln drum. The compositions and operational characteristics of the developed concrete for the repair of linings are given in the table. It should be noted that lightweight heat-resistant concrete on Portland cement is operated at maximum temperatures of 700-800 ° C, and heavy concrete on water glass at temperatures of 800-1200 ° C, and according to the claimed method, the operating temperature of the protective coating can be brought up to 1700 ° C.

Physico-thermal characteristics of heat-resistant concrete No. p / p Compositions of concrete, kg / m ³ The average density, kg / m ³ in the dry state The limit of compressive strength, MPa After firing at operating temperature After impregnation of H ₃ PO ₄ and firing I Portland cement, 1220 PC-400-D-20 -150 5.65 9.1 Expanded clay dust, (lab. oven) (lab. oven) fr. 0.14-1.25 -150 5.5 8.8 Fireclay rubble, (industrial oven) (industrial oven) fr. 5-10 -150 Water -250 II Spent aluminum chromium 2060 26.5 42.6 catalyst, IM-2201 -300 Alumina cement -100 Fireclay rubble, fr. 5-10 -650 Fireclay sand fr. 0.14-5 -750 Liquid glass, (density. 1.36 g / cm ³ ) -350

Surface impregnation of heat-resistant concrete with phosphoric acid made it possible to increase their operational strength by 1.6 times. In addition, the proposed method in comparison with the prototype has other advantages:

- the inventive method allows you to repair the lining at normal temperature, which makes it the most efficient and safe from the point of view of production technology;

- can be used for repair of linings of thermal units at temperatures up to 1700 ° C;

- used raw materials in repair masses are not deficient and many are taken from industrial wastes, therefore, the proposed method is inexpensive among known methods;

- this method is universal, as it allows the repair of linings from piece refractories, as well as from monolithic concrete and concrete elements.

Sources of information

1. Pat. RF №2187484, IPC ⁷ С 04 В 35/65. Hot repair method for lining coke ovens and termite mass for hot repair Gamma-2 KS / MP Utkin, AV Tivin, Yu.V. Belov - No. 2001106535/03; Stated March 14, 2001; Publ. 08/20/2002.

2. Concrete technology / Yu.M. Bazhenov. - Moscow .: DIA, 2002 .-- 500 p.

Claims (1)

A method of repairing the lining of thermal units with heat-resistant concrete, including preparing the surface of the lining followed by applying a special mixture, characterized in that before applying the fine-grained heat-resistant concrete mixture, the surface of the lining is treated with a 50-70% solution of phosphoric acid or acid phosphates, then a fine-grained heat-resistant concrete mixture is applied after hardening of which the obtained layer is impregnated with a 50-70% solution of phosphoric acid or acid phosphates, followed by heat treatment d at the first start-up and output to the thermal unit mode.