JP4370314B2 - Granulation method of highly dehydrated lime cake - Google Patents

Description

  The present invention relates to an improvement in a granulation method for a highly dehydrated lime cake that is generated in large quantities in a sugar factory.

  In a sugar manufacturing process in a conventional sugar factory, in order to remove impurities from the sugar solution extracted from beet, lime milk is added to the sugar solution and carbon dioxide is blown into it, so-called carbonic acid saturation, and so on. Is used, and impurities are adsorbed on the lime cake. The residue obtained by filtering this is a lime cake.

  On the other hand, in order to reduce the amount of lime cake in recent years, it is filtered using a special filter press as a last resort and dehydrated to a moisture content of 27% to 33%. To distinguish, it is called highly dehydrated lime cake.

  Part of this highly dehydrated lime cake is mainly used to correct the acidity of the farmland and replenish calcium, and is sprayed onto the farmland using a dedicated sprayer.

  However, although the highly dehydrated lime cake looks like a solid powder, it contains about 30% of moisture, so if it is sprayed with a spreader as it is, it will adhere to the stirring mechanism of the spreader, or These sprayers have the disadvantage of not being able to use a highly dehydrated lime cake as expected because it presents symptoms such as falling in the hopper.

  In order to avoid these phenomena, methods of forced drying after granulation of highly dehydrated lime cake itself have been tried (JP-A-11-90203, JP-A-2002-331300). This is a major obstacle to commercialization.

For this reason, the inventors of the present invention, as a method of granulating a highly dehydrated lime cake generated in large quantities without forced drying, at a low cost, to a highly dehydrated lime cake first, an appropriate amount of water and cement or magnesium. A granulation method was proposed by adding one or more of solidifying agents ( Japanese Patent Application No. 2005-368178 ).

  However, the granulated product obtained by this method is generally piled up to a height of several meters and then cured and naturally dried for a few dozen days to several tens of days. When an external force is applied to the product and the granulated product is irregularly shaped particles, a part of the granulated product is pulverized and powdered, the yield decreases, or the particles are naturally dried or stored during storage due to their own weight. There are drawbacks such as the occurrence of solidification.

  Therefore, the present invention provides a granulation step of adding a suitable amount of water and one or more of cements or a magnesium-based solidifying agent to a highly dehydrated lime cake as an improvement of the above granulation method, The present invention proposes a granulation method of a highly dehydrated lime cake comprising a granulation step of adding an auxiliary agent to the granulated product obtained in the granulation step.

  That is, in this invention, the uncured granulated product obtained in the granulation process is sized by adding an auxiliary agent in the sizing process, so that the irregular shaped particles are rounded, and therefore, they are piled up to be cured and naturally dried. Even if it is made to part, the part will grind | pulverize and it will become a powder form, a yield will not fall, or solidification of particle | grains will not generate | occur | produce during natural drying or storage by the dead weight.

  In addition, when sizing without using an auxiliary agent, the particles are filled in the apparatus, so that the growth of the particles proceeds, the particles at the end of sizing become somewhat larger, and the particles adhere to each other. It becomes irregularly shaped particles.

  On the other hand, almost no particle growth is observed by adding an auxiliary agent as in the present invention, the roundness of the irregular shaped particles can be improved in a short time, and the particle growth is suppressed in the sizing process. Therefore, the sizing effect can be further increased by increasing the sizing time, and at the same time the anti-caking effect can be enhanced.

  As auxiliaries, talc has a high pH like lime cake, slips well as talc, has good adhesion to lime cake particles, and is also used as a fertilizer carrier, for high safety. Most preferred material.

  In addition, any dry powder can be used as an auxiliary agent. For example, fly ash, lime powder, mineral powder, absolutely dry lime cake, or fats and oils such as stearic acid can be used.

  In addition, an adjuvant is added about 1-4 weight% with respect to a granulated product in a granulation process.

  On the other hand, the cements used in the granulation process include various cements such as Portland cement, blast furnace cement, fly ash cement, slag cement, silica cement, early strength cement, white cement, Arkwien cement, and alumina cement. In particular, when used for spraying on agricultural land or the like, blast furnace cement type B with little chromium elution is preferable.

  When fly ash cement is used as a granulating agent, the resulting granulated product can be used as a snow melting agent, but fly ash is also mixed when cement containing no fly ash is used. Can be used as a snow melting agent.

  In addition to pure magnesium oxide, industrial magnesium oxide or a solidifying agent mainly composed of magnesium can be used as the magnesium-based solidifying agent.

  One or more of these cements and magnesium-based solidifying agents are granulated by adding 2.5% to 5% by weight to the highly dehydrated lime cake in the granulation step, and the crushing strength is 0.1 to 0.2. A granulated product of Kg can be obtained.

  In the granulation step and the granulation step, both a stirring granulation device and a rolling granulation device can be used.

  However, if an agitation granulator is used in the granulation step, the required amount of the auxiliary agent increases to 2% by weight or more with respect to the granulated product. When a stirring granulator is used, the roundness is eventually improved, but it becomes an irregular shape that is slightly distorted at the start of the sizing process, and it is considered that an auxiliary agent is required to fill this recess.

  On the other hand, in the rolling granulator, the particles are round compared to the stirring granulator, so that the required amount of the auxiliary agent can be effective at 1 to 2% by weight based on the granulated product. Therefore, the rolling granulator is more advantageous than the stirring granulator in view of the amount of the auxiliary agent used.

  However, with the rolling granulator, the stability at the initial stage of granulation is somewhat difficult, and it takes a long time to granulate due to the difficulty that it is easy to be lumped and it is difficult to align the cores of the particles at the initial stage of granulation. Therefore, there is a disadvantage that the yield decreases.

  In contrast, the agitation granulator facilitates stable production of uniform granular nuclei at the initial stage of granulation. Therefore, when the particles are granulated, they are transferred to a tumbling granulator. If granulation is performed, the granulation step and the sizing step can be performed efficiently.

  In short, in this invention, the granulated product obtained by adding one or more of cements and magnesium-based solidifying agents to the highly dehydrated lime cake in the granulation step is sized by adding an auxiliary agent in the granulation step. Therefore, even if the irregular shaped particles are rounded, and they are stacked and cured and naturally dried, some of them are crushed and become powdery, the yield decreases, or due to their own weight, During storage, the particles are not consolidated.

  A granulation step of adding a suitable amount of water and one or more of cements or a magnesium-based solidifying agent to a highly dehydrated lime cake, and granulating the granulated product obtained in the granulation step, such as talc A granulation method for a highly dehydrated lime cake comprising a sizing step of adding an auxiliary agent and sizing.

Example 1
Based on the flowchart of FIG. 1, the Example of this invention which used the stirring granulator (Kitakawa Iron Works, Peregiya VZ-100E) or the rolling granulator (Kitakawa Iron Works, Sproa FZ-200) each independently was used. I will explain.

  First, 50 kg of highly dehydrated lime cake is put into the agitation granulator or tumbling granulator, pulverized so that there is no large lump, and then an appropriate amount of additives such as blast furnace cement type B or magnesium oxide is added. The granulation process is started after kneading and mixing well, and then adding water for aggregation. This is performed until the granulated particles grow to the desired size.

  Next, 1 to 4% by weight of talc is added to the granulator as an auxiliary agent to start the granulating step. After the addition, talc was distributed almost within 1 minute, and even if the sizing process was continued for several minutes, almost no particle growth was observed, and the roundness of the particles was improved in a short time.

  The resulting granulated product is stacked, cured and naturally dried, and further sieved to obtain a product. Since the roundness is improved in the granulation process, it is stored when stacked and cured or naturally dried or stacked and stored. In addition to being hard to break against external forces, it was not consolidated from production to storage.

Example 2
FIG. 2 and FIG. 3 are flowcharts of the embodiment of the present invention in which an agitation granulator (Kitakawa Iron Works, Pelegaia VZ-100E) or a rolling granulator (Kitakawa Steel Works, Sproa FZ-200) is used in combination. Based on

  First, after adding 50 kg of highly dehydrated lime cake to the agitation granulator, pulverization is performed, an appropriate amount of additives such as blast furnace cement type B or magnesium oxide is added, kneading is performed, and then water is added. The granulation process is started, but the granulation is completed by growing to granulated particles of 1 mm or less.

  Next, the granular granulated product is transferred to a tumbling granulator and grown to the desired size. Here, 1 to 2% by weight of talc is added as an auxiliary agent, and the sizing is performed for 1 to 2 minutes. The granulated product obtained is stacked, cured and air-dried, and further sieved to obtain a product.

  In this example, the granulation process is completed within 5 minutes, and the process after the granulated product is transferred to the tumbling granulator is also completed within 5 minutes. Such time is within about 10 minutes.

  In the method of this example, the agitation granulator can only perform granulation to a granular form, and when the particles become granular, the particles are transferred to a tumbling granulator for sizing and stirring. When the lime cake granulated product has been transferred from the granulator to the rolling granulator, the next batch can be started with the agitation granulator, so the entire process can be shortened more efficiently than with a single granulator. Can be done in time.

  That is, this embodiment avoids the disadvantages of the agitation granulator and the rolling granulator, and improves the production efficiency by combining the advantages of each other, especially large batch granulation of 500 kg to 1 ton per batch. This is a method suitable for high-dehydration lime cake processing using an apparatus.

  In short, according to the present invention, a granulated product obtained by adding one or more kinds of cements and magnesium-based solidifying agents to a highly dehydrated lime cake is ground or naturally dried or stored in storage. Can be prevented.

Flowchart showing one embodiment of the present invention Flowchart showing another embodiment of the present invention The flowchart which shows the manufacturing process of the granulated product in an Example same as the above.

Claims (2)

A granulation step in which one or more cements or magnesium-based solidifying agents are added to a highly dehydrated lime cake, followed by addition of water for aggregation, and a granulated product obtained in the granulation step A granulation method of a highly dehydrated lime cake comprising a sizing step of adding talc as an auxiliary agent to sizing and a step of stacking the obtained granulated product and curing and drying naturally . The method according to claim 1, wherein a stirring granulator is used in the granulation step, and a rolling granulator is used in the granulation step .

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