JPH0244280B2 - RYUJOHIRYOYOBAINDAA - Google Patents

Description

[Detailed description of the invention]

[Industrial Application Field] The present invention is a granulating agent for granular fertilizers, a granulating agent for agricultural chemicals, a binder used in the production of briquettes, etc. made from slag by-products of the iron and non-ferrous metal industries. Regarding a granulating agent for fertilizer with good properties. [Prior art] Conventionally, when producing granular fertilizer from slag by-product of the iron and non-ferrous metal industry, the granulating agent used for this purpose was a neutralized product of sulfite pulp wastewater produced as a by-product from the sulfite pulp production process. Blackstrap molasses is used either alone or in combination in various proportions. The amount of the granulating agent added was such that the solid content of the granulating agent was approximately 4 to 10% of the solid content of the material to be granulated, and granulation was performed using a pan-type granulator or the like. rear,
Dry with a rotary dryer, etc. Regarding the performance of the slag granular fertilizer produced in this way, disintegration in water and soil is particularly desired from the viewpoint of fertilizer effect. This disintegration in water and soil is specified in the granular fertilizer test method, and the disintegration test in water is
50 granular fertilizers over 2000 microns in water
More than 80% disintegration and dispersion within 24 hours;
In the soil disintegration test, the same granular fertilizer used in the water disintegration test was embedded in soil with a moisture content of 60%.
More than 80% disintegration within 7 days. The above-mentioned slag granular fertilizer using neutralized sulfite pulp waste liquid, waste molasses, etc. as a granulating agent does not fully satisfy these requirements. Therefore, it is an important problem to find a binder that improves the disintegration of granular fertilizers in water or soil, and an example of a solution to this problem can be found in, for example, Japanese Patent Laid-Open No. 16888-1988. According to this, ``By adding polyoxyalkylene alkylphenyl ether sulfate to fertilizer made into granules by adding or mixing a granulating binder with highly basic steel slag as a raw material, and a highly basic steel slag granular fertilizer characterized by improved disintegration and dispersion in soil. The granulation binder described herein is a neutralized product of sulfite pulp waste liquid, waste molasses, and the like. The present inventors attempted to solve the problem by a method different from the method described in JP-A-60-16888. [Problems to be Solved by the Invention] As mentioned above, what is particularly required of slag granular fertilizers is disintegration in water and soil. Conventional granular fertilizers, depending on the type, exhibit a certain level of disintegration and dispersion immediately after production to one month after production, but after a long period of about three to six months, the disintegration becomes extremely poor. Alternatively, there are problems such as not exhibiting disintegration properties even immediately after production, and it is an important issue to discover a binder that has granulation action and disintegration properties. [Means for Solving the Problems] In order to solve the problems of conventional slag granular fertilizers, the present inventors have conducted intensive studies on granulating agents for slag granular fertilizers, and have found that the disintegrability in water and soil has been improved. We have developed an excellent granulating agent for slag granular fertilizers that can be maintained for a long period of time and has a binder effect as a granulating agent. That is, the present inventors focused on the component composition of the sulfite pulp waste liquid produced as a by-product from the sulfite pulp process, and by ultrafiltering the sulfite pulp waste liquid, the concentration of lignin sulfonate in the waste liquid was increased. By removing the molecular part and treating the obtained low molecular part with a hot alkali, a granulated slag granule for fertilizer with better disintegrability was obtained. The fractionation membrane used in the ultrafiltration treatment preferably has a molecular weight cut-off in the range of 2,000 to 100,000. Although it is possible to use a membrane with a molecular weight cut-off of 2000 or less, it is uneconomical in terms of productivity and yield. When a membrane with a molecular weight cut-off of 100,000 or more is used, the removal efficiency of the high molecular weight portion of lignin sulfonate in the sulfite pulp wastewater is poor, and the performance as a granulating agent for slag granular fertilizers is not satisfactory. When the permeate obtained by ultrafiltration is subjected to thermal alkali treatment, the treatment temperature is preferably 80 to 160°C. When the treatment temperature is low, the effect of hot alkali treatment, that is, the effect of improving disintegration properties based on hot alkali treatment, is not observed, and too high temperatures are not economical. The amount of alkali added is preferably 6 to 20%. If the amount of alkali added is small, the disintegrability cannot be improved, and if the amount added is large, it is not economical. The pH of the ultrafiltered permeate can be adjusted using known methods; the more alkaline the pH, the more
Disintegrability tends to improve. [Operation] The components of slag used for granular fertilizer vary depending on the type of furnace, but include CaO, SiO ₂ , MgO,
It contains Al ₂ O ₃ , FeO, MnO, etc., and has the property of gradually combining at room temperature to form insoluble calcium silicate due to the presence of free lime (pozzolanic reaction). This property was the reason why the disintegration property could not be sufficiently satisfied when conventional binders were used. Although the mechanism by which the present invention achieved the disintegration property is not clear, it is presumed from the above-mentioned cause that when the permeate portion obtained by ultrafiltering the sulfite pulp cooking effluent is used as a binder. This is thought to be because it has some effect of controlling the pozzolanic reaction, and this is further promoted by the hot alkali treatment of the permeate portion. [Effects of the Invention] The effects of the present invention are very advantageous in the following points compared to conventional binders for granular fertilizers. (1) Granulation can be performed with a smaller amount added than conventional methods, and inexpensive granules can be obtained. (2) By significantly improving disintegration in water, the effect of fertilization can be promoted. (3) Disintegrability can be maintained for a long period of time. [Example] The effects of the present invention will be explained below with reference to Examples, but the present invention is not limited thereto. Molecular weight cutoff of sulfite pulp cooking effluent
20,000 ultrafiltration membrane, 10% NaOH to solid content was added to the permeated liquid, and the liquid was treated at 120℃ for 2 hours as a binder, and a predetermined amount was added to the material to be granulated, resulting in granulation. After that, it was dried at 100-300°C. The disintegrability of the obtained granules in water and the amount of binder added required for granulation are shown in the table below. In addition, here, blast furnace slag (A),
Converter slag (B) was used.

[Table] From Table 1, it is clear that the product of the present invention has a smaller additive amount and excellent disintegration in water compared to conventional binders.

Claims (1)

[Scope of Claims] 1. A granulating agent for fertilizer containing sulfite pulp cooking waste liquid subjected to ultrafiltration treatment and the permeate portion thereof treated with hot alkali. 2. The granulating agent according to claim 1, in which the ultrafiltration treatment uses a fractionation membrane having a molecular weight cutoff of 2,000 to 100,000. 3. The granulating agent according to claim 1 or 2, wherein the ultrafiltration treatment is adjusted to pH 3 to 10.