DE886751C - Process for the production of coarse-grain potash salt - Google Patents

Description

Method of making coarse grain manure salt From agriculture there is an increasing demand for a coarse-grained quality of fertilizers, to facilitate the machine spreading of fertilizers on the fields.

In the case of potash fertilizer salts, this grain size has so far been used on a small scale achieved in that the hot, saturated potassium salt solutions obtained in the potash works carefully clarified and then slowly put in crystallization boxes to cool were brought, whereby the potassium salt precipitated in coarse crystals. This method however, it is uneconomical because the heat contained in the hot solutions is not is recovered and because clearing out the crystallization boxes with essential Work is connected. This is the reason why the potash industry is slow Cooling in crystallization boxes has gone down more and more and is now generally used the vacuum cooling, in which the heat used to dissolve with that in the vacuum cooling a substantial part of the resulting vapors can be recovered. The product However, with this working method it is not coarse-grained, but very fine.

Various attempts have been made to do this in this process Accruing fine-grained salt to agglomericren into larger grains durable. This z. B. by melting together or briquetting the dried salt and subsequent crushing. However, these procedures are necessary because of the need high energy consumption too expensive.

It has been found that fine-grained fertilizer salt can be converted into durable grains can agglomerate, if one accumulates in the faurication process damp Salt - compresses under moderate pressure and then with stirring, for example in a drying drum, dries. The pressing can for example by means of smooth or profiled rollers or other suitable devices. Essential is only that the pressed body is designed in terms of size and strength so that he disintegrates into a coarse grain during the subsequent drying process. The pressed ones crumble during drying and turn into rounded, firm, storable grains. That The method has the advantage of compacting the salt with a minimum of energy to achieve and still give dense, hard grains without any effort for a re-grinding of the pressed salt.

In the patent 412 $ 64 is already suggested for longer Storage of materials that tend to bake. This means that they can be stored directly in non-baking materials to transfer that they are pressed between smooth rollers. In contrast, will In the present invention, no storable material was obtained during the pressing process, but this only arises during the drying process, which takes place under circulation, in which the compressed mass crumbles and granulates, whereby the grains are dried hard by further removal of water. Accordingly is the energy expenditure required for pressing in the claimed process only a fraction of what the known method requires.

In the method of the patent specification 633 253 are used with knives provided rollers only the crushing of lumpy, pressed material, in particular lumpy fertilizers pressed into plate form.

From the process of patent specification 612 756, in which the granulation of unpressed salt in a rotating horizontal cylinder with built-in rotating divider, if necessary with subsequent drying is intended, the present invention differs significantly - in that - because / that The grain in the end product is made from pre-pressed salt and therefore is considerably stronger and denser.

According to the patent 731 119 inconsistent moist salt mixtures until the salt equilibrium is reached (phase equilibrium) in pressed Form stored for a long time, then dried and, after drying, by crushing converted into grains. Over against this method, the present invention the main advantage that the salt immediately after pressing without a long storage time can be dried, since no reaction is to be awaited, and that no particular one Crushing work is to be expended. Example In a drying drum with a diameter of 2 m and 10 m in length, potash salt was introduced without pressing and dried with fire gases. The dried product contained only about 10 / a grains over 0.5 mm. In the same drying drum became moist potash salt under the same conditions Kind of dried that before entering the drying drum with a roller press was pressed into a 4 to 5 mm thick salt band. The product obtained contained approximately. 50% grains over 0.5 mm in diameter.

Claims (3)

PATENT CLAIMS: 1. Process for the production of coarse-grained potash fertilizer salt by agglomeration of fine-grain potassium salt, characterized in that the moist Pressed salt is dried with stirring. 2. The method according to claim 1, characterized in that a roller press is used for pressing. 3. The method according to claim 1, characterized in that from the dried product the fine fraction is sieved out and, after moistening, repeatedly pressed and dried will.