JPH0459278B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a calcareous composition, particularly a slaked calcareous fertilizer, with improved runoff properties.

In general, calcareous compositions have a number of uses, such as neutralizing agents for acidic substances, fertilizers, disinfectants, disinfectants, civil engineering and construction materials, and chemical reactants. As an example of these, for example, calcareous fertilizer will be described. Calcareous fertilizers are applied for the purpose of correcting soil acidity. For example, there are three types of calcareous fertilizer: calcium carbonate fertilizer obtained by crushing limestone, dolomite, etc., quicklime fertilizer obtained by calcining at about 1000℃ to adjust particle size, and slaked lime fertilizer obtained by hydrating quicklime. It can be broadly divided into

These types of calcareous fertilizers are used depending on the purpose of use, but for example, the solubility in water is calcium carbonate (CaCO ₃ ), which is 1.4 to 1.5 mg/100 g.
(20℃), while slaked lime (Ca(OH) ₂ )
The solubility is 126 mg/100 g (20°C), and there is a large difference in solubility.

The difference in solubility manifests itself in the rate of neutralization reaction with acidic components in soil. Therefore, when comparing calcium carbonate fertilizer and slaked lime fertilizer, even if they have the same particle size, slaked lime completes the neutralization reaction much faster.

On the other hand, quicklime fertilizer has almost the same reaction rate as slaked lime fertilizer if the particle size is similar to the former. However, for ease of handling, the particles are generally in the form of granules or lumps with a particle size of about 1 to 5 mm.

Granular quicklime is hydrated by moisture in the soil and transformed into slaked lime, but at this time, since a much larger amount of water is required for hydration, the produced slaked lime does not pulverize but becomes agglomerated. Slaked lime containing water undergoes a carbonation reaction almost simultaneously with hydration, producing calcium carbonate. Therefore, the neutralization reaction rate of quicklime fertilizer is slower than that of powdered slaked lime fertilizer. In other words, slaked lime fertilizer has a faster rate of soil acidity correction than other forms of calcareous fertilizer, so it shows almost the same effect as the theoretical value, but on the other hand, because of its high solubility, it is subject to rapid leaching by rainwater, etc., and the growth period of plants is delayed. It is not possible to maintain a suitable acidity for a long time.

For this reason, in the case of strongly acidic soil, it is customary to first correct the acidity to the desired level using slaked lime, and then top-dress or simultaneously apply other forms of calcareous fertilizer.

In the slaked lime composition, in particular, the present invention uses polytetrafluoroethylene (hereinafter referred to as PTFE) as slaked lime powder to make the slaked lime powder sustainable without impairing the fast-acting and sharp acidity improving properties of the slaked lime fertilizer, and to reduce runoff and provide sustainability. ) is added, heated, compressed,
The purpose is to fibrillate the PTFE resin by applying shear, capture slaked lime particles in a network, and cause them to aggregate lightly.

The PTFE used in the present invention has the property that when added to fine powder and subjected to appropriate operations, the PTFE itself becomes finely fibrillated without changing the chemical properties of the fine powder. A cobweb-like net was formed, and fine particles of slaked lime were trapped in this net, and this was also confirmed by electron microscopy, which caused the slaked lime to appear to aggregate. Therefore, it is not just a dense agglomeration of fine powder like granulation, but
Since it is an extremely light aggregate of powder particles trapped in a net made of fine fibrils, it is difficult to correct soil acidity and the correction speed.
Compared to slaked lime that has not been treated with PTFE, it has the effect of significantly reducing the amount of leaching caused by rainwater, etc., to almost the same extent.

In the production of the calcareous compositions of the present invention, including calcareous fertilizers, PTFE is added to the slaked lime to maintain its fibrillating cohesive properties by mixing, compacting/shearing, It is necessary to externally apply one type of heating or a combination of both, and with this treatment, if the amount of PTFE added and the treatment conditions are appropriate, PTFE will fibrillate within a few seconds or minutes, and the spiders will A nest-like network is formed, which can aggregate fine particles of slaked lime.

Another method is to pre-disperse PTFE in enough water to hydrate quicklime, dolomitic quicklime, or a mixture thereof to form slaked lime, and use this suspension to hydrate the quicklime. As a result, PTFE fibrillates due to the heat of hydration reaction and stirring, and the generated slaked lime fine particles are trapped in the web-like network of the fibrils, forming slaked lime aggregates as described above. Since the heating operation uses the heat of reaction, it is more energy efficient than the previous example of adding PTFE directly to slaked lime. Furthermore, the PTFE is dispersed extremely uniformly and in a short period of time, so the amount of addition and processing can be reduced. This is an advantageous method that requires less time.

The slaked limestone composition obtained by the present invention, especially when used as a fertilizer, has fast-acting properties and is sustainable as it can correct the acidity of soil over a long period of time.
It goes without saying that it can be applied to various uses as slaked lime or quicklime compositions. This is particularly effective in preventing environmental pollution caused by dust generated during neutralization work, for example.

Next, examples of the present invention will be described.

Example 1 0.17 g of PTFE aqueous suspension (containing 30% by weight of PTFE as solid content) was added to 500 g of slaked lime.
and 0.83g (0.01% by weight and 0.05% by weight of PTFE solids, respectively), mixed lightly in a mortar, heated at 100℃ for 3 hours, kneaded directly in the mortar for 5 minutes, and compressed. / PTFE was fibrillated by applying shearing force, resulting in a product with cohesive properties of slaked lime. These products were treated with PTFE and a soil acidity correction test was conducted using slaked lime as the target.

Add 7.5 g of the above slaked lime to 7 kg of air-dried soil, and sprinkle the mixture with water at a rate of 20 mm/cm ² every day. PH and its substituted calcium were measured.
The results are shown graphically in FIGS. 1 and 2, respectively. From this figure, it was confirmed that the soil acidity correcting ability of the soil with PTFE added was the same as that of the conventional one, and there was less loss due to watering, and the soil acidity correcting ability was maintained over a long period of time. In the diagram ○†

Claims (1)

[Claims] 1. Polytetrafluoroethylene is added to slaked lime or calcined dolomite hydrate, or a mixture of the two, and each of the calcareous particles is coated with fibrillated polytetrafluoroethylene in the form of a network to improve flowability. Slaked lime fertilizer.