Process Line for Production of Foam Iatomite Brick

Contents

1. Introduction

2. Process Part:

2.1. Product Characteristics and Nomenclature

2.2. Process Selection, Justification and Description

2.3. Operating mode and production program of the enterprise

2.4. Raw materials and semi-finished products

2.5. Selection and calculation of the quantity of the main equipment

2.6. Calculation of energy resource requirements

2.7. Production and quality control of finished products

3. Safety and Health

4. List of literature used

1. introduction

Ceramic thermal insulation products are a type of heat insulation materials that are used mainly for the device of thermal insulation of various kinds of industrial furnaces and thermal conductors. The temperature of use of ceramic thermal insulation products depends on the raw materials used for their manufacture and is in the range of 800-1600 ° C.

The main advantages of ceramic thermal insulation products are higher values ​ ​ of temperature resistance, water resistance and strength than other materials used for thermal insulation of power plants and pipelines.

Ceramic thermal insulation products are produced in the form of blocks, bricks, shells and segments.

The properties and production methods of ceramic thermal insulation products have much in common with the properties of construction ceramics and the methods of its manufacture. But there are differences between them, resulting from the greater porosity of these products than construction ceramics. For example, the porosity of wall ceramic articles ranges from 20 to 30% (by volume) and that of heat insulating ceramic articles ranges from 55 to 75% or more. The high porosity of the ceramic thermal insulation articles causes their low bulk weight, low strength and low thermal conductivity.

Depending on the type of the main raw material, ceramic thermal insulation products can be:

• diatomite, the raw material for the production of which is diatomite or trepel;

• vermiculite, obtained from expanded vermiculite and clay binder;

• pearlite, the main raw material for the production of which is expanded pearlite and clay binder;

• lightweight refractory, obtained from refractory clay and quartzite.

The highly porous structure of ceramic heat insulation materials can be obtained by various methods: the introduction and burning out of burnout additives, the introduction of highly porous fillers, gas swelling (gasification) and foaming methods. Fixing of the obtained highly porous structure and giving strength to the products in all cases is achieved only during the firing process, which allows combining the whole variety of these materials into one group of ceramic products.

The methods listed above for producing the highly porous structure of ceramic materials have different significance. Some of them are widely used, while others are limited for various reasons or not at all. The introduction of highly porous components (expanded pearlite and vermiculite) into the moulding mass either significantly increases the cost of the material or reduces its temperature of use. Chemical swelling and swelling of masses during firing are used extremely rarely due to the complexity of the technology. Therefore, two methods have become most widespread: the method of foaming and the method of introducing and subsequently burning out burnout additives. The method of burning additives does not allow to manufacture high-efficiency products with density below 500 kg/m3. Foam iatomite products have a density of 300 kg/m3 and higher. However, the unit production costs and, accordingly, the cost of the foam iatomite brick are much higher than the products produced by the burnout additive process. This is primarily due to the higher fuel consumption for their production. Despite this, the use of products with lower thermal conductivity usually gives a greater economic effect, covering the costs of their manufacture.

In this course project, the technology for the production of foam iatomite bricks will be developed.

2.2 selection, justification and description of the process diagram.

The production of foam iatomite products includes four main technological changes:

preparation of raw materials ;

preparation of foam iatomite mass and moulding of articles therefrom; stabilizing the porous structure of the articles by drying;

formation of porous ceramic tile by firing.

Preparation of raw materials.

Diatomite coming from the quarry is previously crushed and rocky inclusions are removed. Then it is dried to humidity of 510% (quarry humidity of diatomite 50%) and crushed. Combined drying and grinding in a mine mill is preferable to drying in a drying drum followed by grinding in fine milling rolls. In this case, drying and grinding processes are noticeably intensified, fuel and electricity costs are reduced. And the resulting diatomite is characterized by a more uniform humidity.

Sawdust is sieved through sieve with holes not more than 10 mm .

Natural and synthetic foaming agents are used for preparation of technical foam.

Preparation of foam iatomite mass.

Typically, the foam iatomite mass is prepared by mixing the pre-formed diatomite slip and the industrial foam. The ratio of slip to foam depends on the given average density of the finished products. To prepare foam iatomite mass, two- or three-drum foam concrete mixers are used. In the first case, slip is prepared in the lower drum, and technical foam is prepared in the upper drum, which is then added to the slip with continuous stirring. If a three-drum stirrer is used, slip and foam are separately prepared in the two upper drums and mixed in the lower drum.

To obtain a uniform and time-stable psonodiatomite mass, it is necessary to have a slip with a certain density (about 1.3 g/cm3), consistency (immersion of a standard cone 10-12 cm) at a temperature (about 25 ° C). Foam density shall be in the range of 50-65 kg/m3. In order to increase the stability of the foam and therefore the foam iatomite mass, it is advisable to pre-mineralize it. Articles are formed by pouring foam iatomite mass into steel or aluminium molds of appropriate configuration and dimensions. At the same time, a casting machine is used, equipped with several casting sleeves (troughs), under which molds are supplied on the conveyor.

The very high moisture content of foam, reaching 200-250%, causes significant shrinkage during drying of articles (20-25), so the molds are made large in size taking into account shrinkage during drying and firing.

Drying and roasting of articles .

Foam iatomite products are dried in molds, which creates unfavorable conditions for moisture removal, since its evaporation can occur only from the upper surface. This circumstance, as well as significant mass shrinkages during drying, determine the long duration of the drying process. In order to reduce the shrinkage and increase the moisture conductivity of the foam, up to 3 sawdust is added to the slip, but even under these conditions, the drying of the brick lasts 48 hours, and the shell and segments - 75-96 hours.

The peculiarity of drying of foam iatomite products is its soft mode, especially in the beginning of the process (coolant temperature does not exceed 45-50 ° С). Products are fired in tunnel furnaces according to the same mode as products produced by the method of burning additives.

Highly porous diatomite articles, regardless of the manufacturing method, have relatively low strength. Therefore, after mandrel, they should be packed in cardboard or wooden containers.

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