12-13 February 2019 in Moscow hosted the XXVIII international conference "Refractories for industry - 2019"
In a report presented 12 February 2019 at the XXVIII international conference "Refractories for industry - 2019".Demin E. N. (DEMIN SRM GmbH, Germany), Lyalin V. K. (OOO "Spetsogneuporkomplekt", Ekaterinburg, Russia)
Lining of thermal units of refractory materials is quite time-consuming and costly process. Reduction of costs, improvement of technology of carrying out lining works, the requirement to this process.
Today, there are 3 main types of lining materials:
- shaped refractory products kilns and heat-treated;
- concrete materials (gelatine, semi-dry and dry) ways;
- fibrous materials (fibers and products made from fibers).
In recent years, the market of refractory materials is increasing consumer industries that we have not previously been focused. Such consumers include forest, food, agricultural industry, housing and utilities. The consumption of refractories in each case are not as large as metallurgists or engineers, but in General, the number of orders and implementation of refractory only for our company is more than one hundred tons per year. As a rule, at such enterprises there are no technical experts who would be able to provide the conditions to perform high-quality work on the installation of the lining of thermal unit, and also generally lack the equipment to prepare the concrete mix the necessary qualities and conduct heat treatment of the lining in the desired mode.
Therefore, the company, procuring refractory products on the basis only of its physical and chemical indicators, is absolutely not as technologically competent to produce not only the lining, but to bring it to operational mode. In the end, lining either immediately crashes or does not stand the warranty period.
To solve tacosth problems, "Spetsogneuporkomplekt" developed a range of refractory materials that do not require a cumbersome preparatory equipment in the fabrication and installation of the lining, as well as specific knowledge in the technology of refractories. And we confidently believe that these materials will take its place and allow non-core businesses successfully and efficiently produce a new lining, and conduct various types of local or major overhauls of heating units.
These materials will undoubtedly be of interest to our traditional consumers – metallurgists, machine builders, power engineers and refiners.
This article will focus on the method of forming the linings of heat aggregates and several types of materials designed for this method. The goal and objective of the proposed method is to make the process of making the lining more practical, manufacturable and less costly.
We are talking about plastic dense refractory masses which are delivered to the Customer ready and do not require additional preparation, including wetting, or mixing with water, mixing and other time-consuming operations associated with the use of special equipment.
We named such materials Plastic concrete. This name should not cause technical disputes-so this name was formed in the process of working with our customers.
"Spetsogneuporkomplekt" for a long time has produced and produces a moist plastic mass with a moisture content of from 10 to 15% in the form of briquettes of a certain size, as agreed with the customers. Mainly these plastic mass was used for repairs to portions of steelmaking in the form of various abortuary mass, mortar, and protective coatings.
Over time, orders for such products began to increase, there was a demand, not only in aluminosilicate materials, but also on high-alumina and even magnesium composition.
Hence came the idea of produdit and to supply the customer with ready-to-install refractory mass, which can be used as and working, and the insulating layers in different heat units (thermal, heating, furnaces, and boilers for different types of energy).
The key performance requirements for this type of product — high fire resistance, high temperature of the beginning of deformation (softening), high mechanical and thermomechanical properties, good metal and lacoustics.
The initial components of "plastic concrete" was the powder of the refractory filler, often a common fire clay, various plasticizers and sintering additives, and the binder plastic refractory clay. All components were mixed with water, compacted and tasovalis in the form of briquettes in plastic wrap.
Below are the features of our standard weight high-alumina composition, which is for six years and has proved itself from the best side. All the comments of customers and additional requirements for the mass, we take note and try to approach each customer individually.
For physico-chemical parameters the mass complies with the requirements specified in the table.
- chemical composition is determined on a calcined substance;
- allowed production of briquettes other sizes by agreement with the consumer;
- temperature of work: from – 10 to + 35oC.
|Name of the indicator||The norm|
|Refractoriness, onC, at least||1700|
|Al2O3, %, within||37 - 80|
|9 - 17|
|The grain structure, mm||0 - 6|
|Density kg/cm3 in the range:|
|Briquette||1,8 - 2,4|
|After sintering||1,4 - 2,4|
|Shrinkage, %, within||0,8 – 2,1|
|Strength MPa within||35 - 75|
|Weight of briquette, kg, not more||10,0|
|Size of briquette, mm||150*100*250|
|Warranty period of storage of the briquettes, days, not more||30|
Plastic refractory mass brand MWGP comes in the form of rectangular briquettes weighing from 10 to 50 kg, Packed in plastic wrap. At Customer's request products can be made frost-resistant, i.e., its texture retains its ductility at subzero temperatures. This allows for its placement in the winter (down to – 10C) in unheated buildings or shelters.
Piketirovanijah refractory plastic mass delivered to the Customer sealed in plastic wrap in wooden boxes with a volume of 0.5 to 1.0 m3, weighing 1.5 tons.
Briquettes of refractory plastic mass of the desired thickness are laid on a previously cleaned surface. To increase the adhesion with the surface and remove the gaps between the briquettes, the compaction is light compaction weight, and then -- leveling concrete layer. The setting and hardening of the mixture at the initial stage is the result of natural drying and the final drying and sintering of the mass occurs during heating according to the temperature chart.
The advantages of using Plastic concrete:
- Uniformity of mass on chemical and Zernew composition when delivered to the consumer;
- Cost reduction in the organization of the works on the lining of thermal unit due to the reduction of technological equipment;
- The ability to supply liners without the technological backbones (electricity, water);
- The opportunity to work in the winter;
- High environmental friendliness due to the reduction of dustiness in the place of work;
- Reducing the time for lining work as well as for drying and firing of the lining;
- The possibility of withdrawal of technological gradients, barriers and other structural parts of the lining without the use of special equipment;
- The reduction of mass flow per unit volume of the lining. Usually this figure is 10% of the total number of lining materials.
The disadvantage of the brand is MWGP: shorter warranty period of storage mass by reducing humidity and as a consequence of it drying and caking during storage. Currently, we have received mass without increasing humidity with a shelf life of not less than three months after production, which allowed them to equalize with a shelf life of some concrete mixes.
A partial list of enterprises in which work was carried out with the use of plastic masses:
- the city of Erdenet, Mongolia. The lining of the arch, walls, bottom of heating furnace with walking hearth furnace ball mill.
The lining of the arch, walls, bottom of heating furnace with walking hearth furnace ball mill. the city of Erdenet, Mongolia. Installation of PWAS-4000 for waste disposal. The lining of the chamber incinerator drum.
- Dzerzhinsk, Nizhny Novgorod oblast. Installation of PWAS-4000 for waste disposal. The lining of the chamber incinerator drum.
- Seversky pipe plant, Omutninsk metallurgical plant. Gasket Butare steel-teeming ladles.
- The Saratov refinery. The lining of the chamber post-combustion of sulphur in the plant thermocycles.
Our company continues to work to improve consumer properties of the specified masses in the following areas:
- The possibility of using materials of the basic composition, such as magnesite (periclase), dolomite. In addition, without special problems as the filler can be used aluminievaya spinel and chromespinelides are. There is also the possibility of introducing, as necessary, of iron oxide, no damage reduction, retention, and plasticity.
- Ease of installation: installation of the lining without formwork, in both horizontal and vertical planes. Does not require additional equipment such as a mixer.
- Softer and short input mode thermal unit in operation. The schedule of drying and heating at least 2.5 times shorter than the lining concrete.
- The possibility of manufacturing a multilayer lining using plastic heat-insulating layer.
- The real replacement masses on the phosphoric acid type MK-90, MCN-90.
- Higher performance than aluminum the mass of the liquid phosphate binder, such as heat resistance, insulating properties.
In the near future we plan to start production of plastic mass (plastic concrete) for the replacement of mullite-alumina, and corundum mass of the liquid phosphate binder. In the future, the first half of this, 2019, the year of the release of a mass of the spinel and magnesium compounds.