CN1041080C - Manufacturing method of high-purity calcium oxide refractory material - Google Patents

Abstract

The invention provides a method for manufacturing a high-purity calcium oxide refractory material. Its main feature is that lime is used as raw material, any one of plexiglass acetone, gasoline paraffin or anhydrous ethanol calcium oxide mud is used as binder, gasoline paraffin or asphalt is used as moisture-proof agent; after batching, mixing, briquetting, Two times of calcination and waterproofing treatment can produce high-purity calcium oxide refractories with CaO>98%. The invention has easy and cheap sources of raw materials, simple process and equipment, and the manufactured product has strong hydration resistance, and is an ideal refractory material for steelmaking.

Description

Manufacturing method of high-purity calcium oxide refractory material

The invention belongs to the field of refractory materials. It is mainly suitable for the manufacture of high-purity calcium oxide refractories.

The melting point of calcium oxide is as high as 2750±10°C. It is an ideal refractory material for smelting high-quality steel. It should be widely used in steelmaking furnace lining and steel pouring system. However, because calcium oxide has the characteristics of moisture absorption (easy to hydrate), it brings great difficulties to the production, storage, transportation and application of this refractory material. has not been widely used.

In the prior art, "Refractory Materials" 1982, No. 3, page 32 and 1989, No. 2, page 13, have successively reported the development of calcium oxide crucibles. They are made of chemically pure or analytically pure CaO or CaCO3 as raw materials, and are manufactured by isostatic pressing and other molding processes, and their products are only crucibles. The source of raw materials is not easy, the cost is high, the required manufacturing equipment is complicated, and the limitations of its products are large.

A lime refractory material is described on page 886 of the book "Dictionary of Silicates". The manufacturing method of the refractory material is to use limestone (or calcium hydroxide) as the raw material, lightly burn and press the ball, and then calcinate the clinker at high temperature. Mix clinker granules and fine powder into a small amount of dehydrated organic matter (such as paraffin wax, asphalt, etc.), mix, shape, and fire to make products. The implementation of this method is more complicated and difficult. As we all know, dehydrated organic paraffin or asphalt is solid at normal temperature. This kind of material has high viscosity and cannot be ground into fine powder. A process is difficult to carry out. The usual method is to heat the paraffin or asphalt until it reaches a certain flow state before it can be used for mixing. Correspondingly, both the clinker and the agitator must be heated. Therefore, the equipment and process are complicated, and there is certain danger. This is also an important reason why calcium oxide refractories have not been produced industrially.

The object of the present invention is to provide a kind of manufacturing method of new high-purity calcium oxide refractory material, and its source of raw material is wide, and cheap, manufacturing process and equipment are simple, and the produced calcium oxide refractory material product does not hydrate within half a year, and Refractory materials of various specifications and shapes can be produced.

For above-mentioned purpose, the manufacturing method of high-purity calcium oxide refractory material of the present invention comprises the following steps (operation):

Raw material preparation, removal of surface inclusions, lime digestion into lime slurry and filtration, drying and briquetting (pressing), calcination, crushing, mixing, molding, sintering (firing), waterproofing treatment, and packaging.

Each step (operation) is now described as follows:

(1) Raw material equipment

Lime and anhydrous binder are used as raw materials in the invention, and the raw material ratio (weight %) is: 80-95% of lime and 5-20% of anhydrous binder.

The anhydrous binder is any one of plexiglass acetone, gasoline paraffin or anhydrous ethanol calcium oxide mud.

(2) Remove surface inclusions

Use physical methods (such as sieving, etc.) to remove the inclusions in the lime.

(3) Lime is digested into lime slurry and filtered

Digest the lime after removal of inclusions into lime slurry with water, and filter to remove inclusions in the lime slurry and improve the purity of the lime slurry.

(4) Drying and briquetting

After the lime slurry is filtered, it is dried, and after drying, it is pressed into a blank.

(5) Calcination

The pressed blank is put into a calciner for calcination so as to calcine the clinker, which is calcined

The temperature is 1450-1750°C, and the calcination time is 10-36 hours.

(6) Smash

The calcined clinker is crushed into fine powder.

(7) According to the ratio of raw materials, lime powder clinker and anhydrous binder are added to the mixture for mixing to make a mixture.

(8) Forming

According to needs, the mixture is made into parisons of different shapes and specifications.

(9) Sintering (firing)

Put the final parison into a moisture-proof calciner for sintering, the sintering temperature is 1400-1700° C.; the sintering time is 13-25 hours.

(10) Waterproof treatment

The sintered calcium oxide refractory product, after being released from the furnace, is immersed in any moisture-proof agent in gasoline---paraffin or asphalt, and is subjected to waterproof treatment. The treatment time is 4-25 minutes. After treatment, it becomes the final product of the present invention. Calcium oxide refractory products. The products are packaged in plastic bags for storage and transportation.

The calcium oxide refractory material produced by the present invention has a purity of up to CaO>98%, will not be hydrated within half a year, and can be made into refractory materials of various shapes and specifications, and is widely used in steelmaking furnace linings and steel pouring systems. It is an ideal refractory material for smelting high-quality steel.

Compared with prior art, the present invention has following advantage:

(1) It can produce high-purity calcium oxide refractory materials with CaO>98%, various shapes and specifications, and waterproof.

(2) The source of raw materials is easy and the cost is low.

(3) The manufacturing process and equipment are simple. Especially the mixing of lime slurry and anhydrous binder can be carried out at room temperature without heating.

Example

Using the manufacturing method described in the present invention, five batches of high-purity calcium oxide refractory materials were produced. The proportioning ratio of the raw materials and anhydrous binder used is shown in Table 1. Table 2 lists the process parameters of the two calcinations before and after, and the moisture-proof agent and treatment time used in the waterproofing treatment are shown in Table 3.

The product specifications, compressive strength and high temperature oxidation resistance of the five batches of high-purity calcium oxide refractories produced are listed in Table 4. Five batches of products were placed in the normal temperature atmosphere, and after six months, no hydration phenomenon was found.

Table 1 embodiment raw material and anhydrous binder proportioning (weight %) batch number lime Anhydrous binder Plexiglass acetone gasoline paraffin Anhydrous ethanol calcium chloride mud 1 82 18 / / 2 80 20 / / 3 85 / / 15 4 94 / 6 / 5 93 / 7 /

The technological parameter of twice calcining of table 2 embodiment batch number first calcination second calcination Calcination temperature °C Calcination time hours Calcination temperature °C Calcination time hours 1 1750 10 1580 25 2 1450 14 1580 15 3 1680 36 1400 25 4 1680 36 1700 13 5 1580 13 1570 18

Desiccant agent and processing time used in the waterproof treatment of the embodiment of table 3 batch number 1 2 3 4 5 Desiccant asphalt asphalt asphalt gasoline paraffin gasoline paraffin processing time 10 minutes 15 minutes 20 minutes 5 minutes 5 minutes

Table 4 embodiment product specifications and physical properties batch number Product size mm Compressive strength MPa CaO content% 1 50×50×70 18 99.2 2 φ70×70 18 99.2 3 φ70×70 18 99.2 4 120×130×260 20 98.97 5 120×130×260 20 98.97

Claims (1)

1, a kind of manufacture method of high-purity calcium oxide refractory materials comprises the steps: that raw material outfit, lime slaking become lime white, pulverizing, batch mixing, moulding, sintering, preventing hydration to handle, and is characterized in that:

(1) proportion of raw materials (weight %) is: lime 80-95%, anhydrous binder 5-20%;

(2) anhydrous binder be in synthetic glass acetone, gasoline paraffin or the dehydrated alcohol calcium oxide mud any;

(3) raw material lime is removed surface inclusion with physical method, and after being digested to lime white, filters;

(4) waste base is dried, is pressed into to lime white after filtering again;

(5) waste base is at calcining kiln roasting grog, and calcining temperature is 1450-1750 ℃, calcination time 10-36 hour;

(6) grog after the calcining adds in the mixer in the lump with anhydrous binder and to mix after crushed, makes compound, and as required, compound is made the parison of different shapes and specification;

(7) parison carries out sintering in moistureproof calcining furnace, and sintering temperature is 1400-1700 ℃, time 3-25 hour;