KR100237557B1 - Cement mortar composition from waste materials - Google Patents

Abstract

The present invention is a cement mortar composition for recycling waste slag, waste foundry sand, and coal ash, which are industrial wastes, as a substitute for sand, and aims to reduce costs due to environmental pollution prevention, natural damage prevention, and waste material recycling.

According to the present invention, by mixing 30-80 parts by weight of waste slag, 10-40 parts by weight of waste foundry sand, 5-20 parts by weight of coal ash, 15-20 parts by weight of cement, and 20 parts by weight of water, brick, sidewalk block, compatible block, boundary stone, fume pipe When manufacturing building materials, etc., it has better compressive strength and lower water absorption than concrete using sand.

The cement mortar composition according to the present invention can be widely used as a substitute for cement mortar using conventional sand.

Description

Cement Mortar Composition Using Waste

The present invention relates to a method for producing semantic mortar using waste.

In general, cement mortar is made by mixing sand, stone powder, cement and water in a certain ratio, and then pouring it into a mold to be molded into a building material of a certain standard. However, cement mortar made of sand has traditionally been used in the past, but it is weak in strength, high in water absorption, and damages rivers and rivers to collect sand, causing environmental pollution and destroying ecosystems. The depletion of oil makes it difficult to collect sand, increasing the cost of building materials.

In order to solve this problem, many attempts have been made to resource industrial waste. Korean Patent Publication No. 91-18325 uses briquette materials, waste synthetic resin asphalt, etc. as building materials. In addition, Korean Patent Publication No. 92-4297 completely incinerates waste paper, and then adds clay to the remaining material and calcinates it at a high temperature, and Korean Patent Publication No. 94-4379 discloses waste lime, cement, Silicate salts, pigments, surfactants, etc. are mixed and used as building materials. Korean Patent Publication No. 94-25980 is used to mix leather waste, cement, quarry crumb, sand, etc. The preparation of the boundary stone, Korean Patent Laid-Open No. 96-29048 describes a method for reusing building waste as building materials.

However, the conventional method of using waste as a building material has a high cost and actual construction by complicating the processing process by excessively using additive materials or using a strong alkaline waste steel casting sand to mix the waste material with sand or cement. Even if it is used as a material, the difference between the existing building materials and physical properties is so large that it is rarely adopted in construction, so it is not practically used.

The present inventors focus on the fact that the bulk slag of the steel mill, the Feju iron foundry sand of the foundry plant, the coal of the thermal power plant, etc. are mostly not recycled, but also bear the burden of disposal costs. As a result of continuing research with a focus on solving the same problem, the development of economical and physically superior waste cement mortar was developed.

In other words, waste slag and castings, which are the wastes of steel mills, have been repeatedly studied for the use of waste that can replace the sand, which is depleted in resources and the cost of collecting is increasing, which increases the difficulty of supplying construction materials. The foundry cast iron foundry found in the plant could be used as cement mortar instead of sand.

Physicochemical properties of these wastes are specific gravity 1.89 ~ 2.77, particle size 4,000 ~ 5,000㎠ / g, content of SiO ₂ 31.2 ~ 35.7%, Al ₂ O ₃ 12.2 ~ 16.3%, CaO 38.0 ~ 45.0%, MgO 4.7 ~ 7.4% , FeO 0.05 ~ 1.0%, MnO 0.21 ~ 1.42%, S 0.49 ~ 1.51%, TiO ₂ 0.38 ~ 1.99%, Na ₂ O 0.16 ~ 0.42%, K ₂ O 0.22 ~ 0.56%, containing heavy metal below the acceptable standard Doing.

Therefore, the mortar was manufactured by mixing slag slag and cast iron cast sand with cement, and the fracture load, compressive strength, water absorption rate, etc. were much better than the building materials using sand, while the average load increased by 15-20%. There is no problem to use it for the ground, but when it is used for the stacking of the structure, there is a problem of raising the construction cost due to the reinforcement of the foundation work and the steel structure.

In order to solve this problem, a number of wastes have been researched and tested, and the waste ash of coal used in thermal power plants is reduced physically and chemically. As a building material, it has suitable components (SiO ₂ 50 ~ 60%, Al ₂ O ₃ 20 ~ 30%, Fe ₂ O ₃ 0.5 ~ 5%, CaO 10 ~ 20%) and mixed with bulk slag for use in cement mortar It has been found that the fluidity, strength and hygroscopicity prevention are improved.

In the past, the bulk slag and the coal ash could only be used as auxiliary miscellaneous materials such as roads, aggregates, landfills, asphalt aggregates, and fertilizers due to the limitation of physical properties.

The reason why the bulk slag or coal ash was not used as a material for a single building material such as blocks or bricks is because the physical properties of these wastes are worse than those of sand, and the present inventors do not use them as auxiliary materials, but without using sand. The present invention was completed after efforts to replace sand with only these wastes.

1) Raw material collection

Mass slag: Collects waste slag, a stone mass waste produced as a by-product when iron ore is smelted at a steel mill.

Waste cast iron casting sand: Collects waste cast iron casting sand in the form of lumps that are used after the mold is manufactured in the foundry.

Coal ash: Collects coal ash in the form of lumps or fine powders produced during combustion in a coal-fired or cogeneration plant using bituminous or anthracite coal.

2) Raw material grinding and screening

Lung Slag: The collected waste slag is pulverized into fine powder and the slag is sorted to the size of 1-2mm or less in the classifier.

Waste cast iron casting sand: Crush the waste cast iron casting sand in the form of a powder into a powder and then sort it into a size of 0.5-1.0mm or less in a classifier.

Coal ash: Crush lump or powdery coal ash with a pulverizer and sort it to the size of 0.1mm or less in the sorter.

3) Formulation and Mixing

Put 30-80 parts by weight of waste slag, 10-40 parts by weight of waste cast iron casting sand, 5-20 parts by weight of coal ash, 20-30 parts by weight of cement, and an appropriate amount of water into a mixing tank and stir.

As a result of a comparative test according to the KS criteria for the bricks prepared through the normal curing period with the bricks and sand prepared as described above are shown in Table 1, the strength of 30% or more and the absorption rate of 60% or more were obtained. .

It is not known exactly why this product has better quality than the control, but the bulk slag dissolves iron and ore at high temperature and decomposes impurities and oxides to form silicon oxide or calcium oxide of dense structure and mix concrete with cement and water. It is judged to exhibit particularly hydraulic properties when molded. Also, in the case of waste cast iron sand and coal ash, silicon oxide and aluminum oxide are formed by removing impurities at high temperature, and thus there is no hydraulic property. As the activity becomes stronger, the compressive strength and water absorption rate are better than that of general cement bricks.

The invention is illustrated in more detail by the following examples.

Example 1

Crushed bulk slag (components as described above) from Gwangyang Steel Mill was crushed to 1-2mm size, and waste cast iron foundry sand from Asian automobile plant was crushed to size 0.5-1.0mm and then coal ash from thermal power plant. Was milled to a size of 0.1 mm or less. 40 parts by weight of the selected bulk slag, 30 parts by weight of cast iron cast sand, 10 parts by weight of coal ash, and 20 parts by weight of cement were added to the mixer, followed by stirring while slowly adding 20 parts by weight of water, and then poured into a (90 × 90 × 57 mm) mold. 500 cement bricks were manufactured by molding, and then cured at wet and dry at 4,000 ° C. or higher for 7 days. The results of testing the compressive strength and the absorption rate according to the KS standard for bricks manufactured through the curing period are shown in Table 2 below.

Example 2-10

Table 2 shows the compressive strength and water absorption test results of the bricks prepared in the same manner as in Example 1, but with different mixing ratios.

According to the present invention, by recycling waste as a resource, the sand resources collected for concrete can be preserved and environmental damage due to landfill or quantitative waste can be greatly reduced.

The present invention is to use the waste in place of sand, when producing a concrete product, the effect is much better in terms of quality such as compressive strength or water absorption than concrete using sand.

Therefore, the cement mortar according to the present invention can be widely used as a substitute for cement mortar using conventional sand in the manufacture of building materials such as bricks, sidewalk blocks, compatible blocks, boundary stones, and fume pipes.

Claims (1)

In cement mortar using waste, gradually add waste slag, waste cast iron foundry sand, 30-80% by weight of waste slag obtained by pulverizing coal ash, 10-40% by weight of waste cast iron foundry sand and 5-20% by weight of coal ash with a predetermined amount of water. Method for producing a cement mortar using a waste, characterized in that consisting of a series of processes that are sufficiently mixed by stirring while mixing.