DE1092601B - Process for the production of a quicklime suitable for carbide production - Google Patents

Description

GERMAN

LIBRARY OF THE GERMAN PATENT OFFICE

Large amounts are involved in the manufacture of acetylene from carbide Quantities of hydrated lime in the form of sludge or powder, which can only be used under favorable circumstances as a construction or Lime fertilizer can be deposited. In most cases a more or less large part of the Hydrated lime can be stored as waste. There has therefore been no lack of attempts to find the hydrated lime returned to the carbide process. For this purpose it is either molded and so in the Carbide furnace introduced; mostly, however, it is first burned back to calcium oxide by using it as a powder or in the form of pellets and granules in a shaft or rotary kiln at temperatures above 550 ° C is drained.

It is difficult to obtain calcium oxide suitable for carbide production by burning hydrated lime obtain. A very reactive white lime is produced at low firing temperatures. This disintegrates during transport and storage due to mechanical stress and moisture attack below strong dust development and thus causes difficulties and losses in furnace operation. If you try Burning and sintering at higher temperatures is only possible if special procedural measures are strictly observed avoid the formation of large sinter blocks. These blockages require special furnace constructions and even there lead to unpleasant disturbances.

The presence of iron in free and bound was found to be a major cause of block formation Form recognized in carbide lime. This iron comes partly from the impurities in the fresh lime and the coal, on the other hand from the iron electrode sheaths and smear rods into the calcium carbide, is present in it as metallic iron or as low-percentage ferrosilicon and passes through without change the carbide gasification process.

When burning the hydrated lime it combines with the lime to form ferrites and silicates, which are one bring about a particularly strong reduction in the melting temperature and thus cause the dreaded furnace blockages.

Various methods are used to remove the iron and ferrosilicon. When present In liquid suspensions, iron and ferro-silicon are separated on the basis of their greater specific characteristics Weight hydraulically. In the case of hydrated lime powders, the difference in specific weight, z. B. in windsight! Are exploited. However, in both cases, it is difficult to find that in a very fine form To remove iron and ferrosilicon to a large extent, without at the same time large amounts of hydrated lime to be deposited with.

It is also known to use iron and the low-percentage method of manufacture

one for carbide production

suitable quicklime

Applicant:

Wacker-Chemie GmbH,
Munich 22, Prinzregentenstr. 20th

Dr. Eduard Enk, Dr. Wolfgang Leicher
and Dipl.-Ing. Dr. Walter Schindelin,

Burghausen (Obb.),
have been named as inventors

Removing ferrosilicon from the hydrated lime with the help of magnets. That resulting from carbide gasification However, hydrated lime powder has the unpleasant property that it compacts and cakes easily. On the one hand, this leads to disruptive deposits on the machine equipment, such as magnetic drums or bands, on the other hand the iron present in coarser parts can be made from this compacted powder and ferrosilicon are magnetically extracted. The finer parts, however, are only affected by very strong magnetic fields to be removed and then so strongly surrounded by hydrate that the lime losses increase considerably.

It has now been shown that a smooth deposit can be obtained can be achieved by means of magnets if the hydrated lime powder falls freely through the magnetic field drops. This keeps the powder in such a loose state that the coarse and also the fine iron and Ferrosilicon parts can be removed while the purified hydrated lime powder falls down without that any deposits form on the machine equipment and thus continuous operation is possible.

The hydrated lime purified in this way can be burned and sintered at higher temperatures without being too large To bake blocks together. This means a big one

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Relief in furnace operation, as this becomes more even and small changes in the operating conditions, such as the amount and distribution of coal, draft ratios, etc., no longer influence it so strongly.

example

In a shaft furnace, unpurified or purified hydrated lime in the form of cylindrical compacts is added Use of an anthracite mixed fire burnt. The calcium oxide discharged gives the following picture:

Coal rate Firing temperature Untreated hydrated lime Event Treated hydrated lime 7o about ⁰ C soft white lime, 30% sintered soft white lime, 30% grained 5.5 800 White lime, 60% sintered, no blocks 6.0 900 White lime, 60% sintered, small blocks 80% sintered, no blocks 6.5 1100 80% sintered, large blocks 100% sintered, no blocks 7th 1300 100% sintered, large blocks, Oven relocation

The tests show that after a removal of 6.5 or 7% carbon rate, iron ingots form and ferrosilicon before briquetting is neither at 20, although the discharge is sintered into individual pieces.

Claims (1)

Claim: Process for the production of a calcium oxide suitable for carbide extraction from carbide lime by removing iron and iron compounds by means of magnetic separation, characterized in that the hydrated lime is guided in free fall through a magnetic field. ι 009 647/122 11.60