CS214011B1 - Method of and apparatus for the production of pure pulverized caustic hydrate from waste carbide lime - Google Patents

Description

The invention relates to a treatment method and a device for treating carbide waste lime.

; Waste carbide lime is a pasty suspension of lime hydrate (Ca (OHJg)), which is produced as a waste product in the production of acetylene by hydration of calcium carbide (CaCg).

The methods of treatment of waste carbide lime so far used are based on its pre-drying and subsequent firing, the product of which is burnt lime (CaO). Installations that process carbide lime waste only operate in the GDR and Píí (except CSR) The only manufacturer® of calcium carbide acetylene / · the essence is a kiln (shaft or rotary / for caustic / regeneration / carbide lime). (waste carbide lime is very energy intensive due to high heat consumption (drying, firing). The product of the processing is burnt lime (CaO), i.e. a material different from the chemical side of lime hydrate (CaOH).

a more violent method of treating waste lime hydrate (but not carbide lime) is the method proposed by Tonas®, n.p. The first step was to concentrate the original lime hydrate suspension by filtration and, after reducing the moisture content to 30% (w / w), to mix the ground quicklime to give the resulting fertilizer product. The disadvantage of this process is that the resulting product does not meet the requirements for pure calcium hydrate qualitatively because it is a mixture of calcium hydrate (Ca 2 H 3) and limestone (CaCO 2).

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The above-mentioned deficiencies are eliminated by the proposed method of treating carbide lime by mixing with quicklime (lump or ground) in such a proportion that the resulting product is a dry powdered hydrate with properties satisfactory. 72 The proposed method utilizes the mechanism and thermal effect of the chemical process , which is based on the reaction between the moisture content of waste carbide lime (HgO) and quicklime (CaO).

The mixing of carbide waste lime with a moisture content of 10% to 70% (w / w) with quicklime is carried out in the proposed plant, which is based on continuous mixers with a shaft design that provides simultaneous homogenization, disintegration and transport of the reacting mixture. The device is energy efficient, since it does not need any heat supplied from outside to remove moisture from the carbide lime.

A further advantage of the proposed plant from an ecological point of view is that it treats waste which in its raw state is expensive to store and destroys the farmland and the bottom; water.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is an overall diagram of the apparatus; FIG. 2 shows a detail side view of the continuous mixer and FIG. 3 is a cross-sectional view of the continuous mixer along line A-A.

The mixer consists of a casing 1, the cylindrical bottom of which flows into planar sidewalls, the bottom of which has a material outlet opening 17. The housing 11 is terminated on both sides by faces 8 in which bearings for receiving the shaft 2, on which the blades 13 and the rods 4 are fixed in the form of screws, are driven by the drive unit 9. The top cover 5 m <inlet openings 6 and is attached to the housing 1.

Waste carbide lime is fed through the inlet openings 6 with a moisture content of from 10% to TO% by weight and ground or lump quicklime. By rotating the shaft 2, the material is simultaneously mixed, disintegrated and conveyed to the outlet opening 7 by means of the blades 2 ^{and the} bars 4.

During agitation, the calcined calcareous calcite is hydrated, and at the same time the heat released in the chemical reaction dries the calcium carbonate product. The choice of the number of mixers depends on the input moisture of the carbide lime, the reactivity of the lime brandy and the desired plant performance.

Examples of waste carbide lime treatment:

Example # 1

To the continuous mixer model of the invention and for 10 minutes, it mixed 20 kg of 70% w / w waste carbide lime and 20 kg of ground quicklime. The resulting product was 35 kg of dry powdered hydrate pure (according to & M 722247). Difference, ie. 5 kg is for evaporated water.

Example no. 2 1

In the continuous mixer model of the invention, 25 kg of 70% w / w carbide lime was mixed with 25 kg of crushed quicklime with a grain moisture of up to 20 mm for 10 minutes. After separation, the coarser fraction was the product of 40 kg of dry powdered lime hydrate pure (according to ČSN 722247), while the grain size of the waste (total 5 #) did not exceed 3 mm.

Example no. 3

To edit the hydration unit with a power of 7 th ^"1 prlebežne the mixed waste carbide lime with moisture 54 Μ quick lime with crushed grains of the veíkostl 10 a * = ^3: 2 Výaled214 011

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The final product was pure lime hydrate in accordance with ČSN 722247.

Claims (2)

OBJECT OF THE INVENTION Process for the production of pure calcium hydrate powder, characterized in that waste carbide lime having a moisture content of from 10% to 70% by weight. mixed with ground or crushed quicklime in ratios of 6: 1 to 2: 3 depending on the activity of the quicklime used and the input moisture of the waste carbide lime, the moisture content of the powdered lime hydrate not exceeding 3% by weight. 2. Apparatus for the production of powdered lime hydrate according to claim 1, comprising continuous stirrers with vane shafts (2), characterized in that on the shafts (2) are mounted on separate or common helical blades with blades (3) fixed by rods (4). /, intended for material disintegration.