JPS6365607B2 - - Google Patents

Description

[Detailed description of the invention]

INDUSTRIAL APPLICATION FIELD The present invention relates to a method for improving the fluidity of lime powder, and more specifically, to a method for improving the fluidity of lime powder that is operationally safe, simple and reliable. . Prior art and its problems Lime powder, especially quicklime powder, has been effectively used in the manufacture of refractories, as a treatment agent for pulp and paper, as a desulfurizing agent, etc. However, since quicklime powder has hygroscopic properties, it cannot be used as is. It becomes inconvenient to handle because it absorbs moisture and loses fluidity. To this end, a conventional method for improving the fluidity of lime powder such as quicklime is to treat lime powder with methylhydrodiene polysiloxane, terminal trimethyldimethylsiloxane, terminal hydroxyl dimethylsiloxane, terminal trimethylsiloxymethylmethoxypolysiloxane, etc. has been proposed (Japanese Unexamined Patent Publication No. 1983)
−47223, JP-A-58-120519, JP-A-57-
7085, Special Publication No. 57-7087). However, in the method of using methylhydrodiene polysiloxane as a fluidity improver for lime powder, hydrogen gas is generated as the treatment progresses, creating a risk of explosion. For example, 100g of lime powder Methylhydrodiene polysiloxane represented by
When treated with 0.1g, up to 36ml of hydrogen gas is generated. Therefore, when processing lime powder in containers or storing processed products, use inert gas or nonflammable solvents (such as chlorinated solvents) to keep them out of the explosion range of hydrogen gas.
It is necessary to dilute it with water or make the opening of the container larger, but the dilution process is complicated and
Particularly when diluting with a non-flammable solvent, there is the trouble of having to remove the solvent in a subsequent process. Furthermore, if the opening of the container is made large, there is a risk that the powder will scatter as the treatment progresses and the fluidity of the lime powder increases. In addition, when trimethylsilyl terminal or dimethyl polysiloxane terminal hydroxyl group is used as a fluidity improver, a long processing time is required, a considerable amount of time is required for the fluidity improvement effect to appear, and strong stirring is required. Processing must be performed, and there is a problem with processability. Moreover, the process using terminal trimethylsilylmethylmethoxypolysiloxanes makes the compound itself complicated to produce and expensive. SUMMARY OF THE INVENTION In view of the above circumstances, the present inventors have conducted intensive studies on a method for improving the fluidity of lime powder that is safe to work with and has good workability.As a result, the following general formula () (R ³ ₃ SiO _1/2 ) _l (R ² ₂ SiO _2/2 ) _n (R ¹ SiO _3/2 ) _o … () (However, R ¹ , R ² , and R ³ are the same or different types of monovalent carbonization. Hydrogen group, l = 0 to 35 mol%, m
=35-95 mol%, n=5-30 mol%, l+m+n
= 100 mol%) has excellent properties as a lime powder fluidity improver.
It has been found that the above object can be achieved by performing the treatment using 0.02 to 1 part of the compound (the same applies hereinafter). That is, when lime powder is treated using a compound containing 5 to 30 mol% of R ¹ SiO _3/2 units as described above, no hydrogen gas is generated and flammable gases such as methyl alcohol are not generated. Since there is little generation of hydrogen gas, it is safe to work, and since there is no generation of hydrogen gas and little methyl alcohol generation, there is no need to dilute with inert gas or nonflammable solvent.
It can be worked at room temperature, does not necessarily require strong stirring, and can improve the fluidity of lime powder in a relatively short amount of time, making it easy and reliable to work with. The inventors have discovered that the fluidity of lime powder can be improved, and since the above compound is relatively easy to produce and inexpensive, processing costs can be reduced, leading to the present invention. The present invention will be explained in more detail below. Structure of the Invention The method for improving the fluidity of lime powder of the present invention can be suitably employed to improve the fluidity of lime powder such as quicklime, slaked lime, calcium carbonate, etc., especially lime powder with a particle size finer than 100 mesh. Lime powder is expressed by the following general formula () (R ³ ₃ SiO _1/2 ) _l (R ² ₂ SiO _2/2 ) _n (R ¹ SiO _3/2 ) _o … () (However, R ¹ , R ² , R ³ are the same or different monovalent hydrocarbon groups, l = 0 to 35 mol%, m
=35-95 mol%, n=5-30 mol%, l+m+n
= 100 mol%) is characterized in that it is treated with one or more organopolysiloxanes. Here, as the organopolysiloxane of formula (), one in which R ¹ , R ² and R ³ are each a lower alkyl group such as a methyl group or an ethyl group is preferably used. In particular, methylpolysiloxanes in which R ¹ , R ² , and R ³ are each methyl groups, l = 2 to 35 mol %, m = 40 to 93 mol %, and n = 5 to 25 mol % are preferably used. In this case, the above ()
In the formula, the R ³ ₃ SiO _1/2 unit is not necessarily required, but is introduced to adjust the degree of polymerization, and its mol%
As mentioned above, it is preferably 35 mol% or less, particularly 2 to 35 mol%. In addition, R ¹ SiO _3/2 units are necessary to accelerate the expression of the fluidity improvement effect when processing lime powder, and its mol% is 5 to 30
The mole%, particularly preferably 5 to 25 mole% as mentioned above, is less than 5 mole%, the fluidity improvement effect is delayed, and more than 30 mole%, it is difficult to obtain a stable polysiloxane fluid. This makes it difficult and undesirable. In addition, the above compound has a viscosity of 1 to 25°C.
500 cs, especially 1 to 100 cs is preferred. The organopolysiloxane of the above formula () can be produced by a known method, and is generally a co-hydrolysis method of silanes having corresponding hydrolyzable groups (chlorine, etc.) (if necessary, using toluene, etc.). solvents may be used). For this reason,
Polysiloxane fluids are generally obtained containing several percent or less of hydroxyl groups or alkoxy groups due to manufacturing considerations. In this case, a method of polymerization using a catalyst such as activated clay or sulfuric acid may also be adopted to adjust the viscosity. In the present invention, lime powder is treated using the organopolysiloxane of the above formula (), but in this case, the amount of the above compound used is per 100 parts of lime powder.
The amount used is 0.02 to 1 part, and neither the amount used is less than 0.02 part nor more than 1 part, the lime powder fluidity improving effect is not sufficiently exhibited. In addition,
The preferred amount range of the above compound is 0.1 to 0.5 parts per 100 parts of lime powder. The method for treating lime powder with the above compounds is as follows:
A commonly used method can be used, such as adding the above-mentioned compound to lime powder and uniformly mixing the above-mentioned compound into the lime powder using an appropriate stirring method such as shaking and stirring. In this case, stirring does not necessarily have to be strong stirring. The treatment temperature is not particularly limited and can be from room temperature to 100°C, but the treatment is sufficient at room temperature, and according to the present invention, lime powder with high fluidity can be reliably obtained by mixing at ambient temperature. can. Further, the treatment time is not limited, but is usually 10 minutes to 1 hour, and according to the present invention, the fluidity of lime powder can be improved with a relatively short treatment time. In addition, in the present invention, since hydrogen gas is not generated and the amount of methyl alcohol generated is very small, there is no need to dilute with inert gas or nonflammable gas, and the treatment can be carried out in an air atmosphere. Can be processed in solvent. Effects of the Invention As described above, the method for improving lime powder fluidity of the present invention uses a specific amount of a specific organopolysiloxane, thereby eliminating the generation of hydrogen and reducing the generation of methyl alcohol, resulting in safe processing. It can be processed at room temperature in a relatively short time, and lime powder with sufficiently high fluidity can be reliably obtained by using only a small amount of processing agent, and it is also inexpensive. be. EXAMPLES Hereinafter, the present invention will be specifically explained by showing examples and comparative examples, but the present invention is not limited to the following examples. Examples and Comparative Examples Methylpolysiloxane was obtained by using (CH ₃ ) ₃ SiCl, (CH ₃ ) ₂ SiCl ₂ and CH ₃ SiCl ₃ in the proportions shown in Table 1 and hydrolyzing them according to a conventional method. I got it.

[Table] Next, 200 mesh passes (250 mesh passes 8
%, 325 mesh pass 40%) was added with 0.1 part and 0.3 parts of the above methylpolysiloxane, respectively, and placed in a 300 c.c. round bottom flask with a stirrer, and mixed and stirred at room temperature for 1 hour. Summer. For comparison, the same treatment was carried out using a dimethylsiloxane with a terminal trimethylsilyl group (Comparative Example 1) having a viscosity of 20 cs at 25°C and a dimethylsiloxane containing a terminal hydroxyl group (Comparative Example 2) with a viscosity of 20 cs at 25°C. The angle of repose of the quicklime treated using the above method was measured to evaluate its fluidity. The results are shown in Table 2. The angle of repose of untreated quicklime was 53°.

【table】

[Table] From the results in Table 2, it was found that the fluidity of quicklime powder could be improved in a short time by using the organopolysiloxane of the present invention.

Claims (1)

[Claims] 1 The following general formula () (R ³ ₃ SiO _1/2 ) _l (R ² ₂ SiO _2/2 ) _n (R ¹ SiO _3/2 ) _o … () (However, R ¹ , R ² and R ³ are the same or different monovalent hydrocarbon groups, l = 0 to 35 mol%, m
=35-95 mol%, n=5-30 mol%, l+m+n
1. A method for improving the fluidity of lime powder, which comprises treating 100 parts by weight of lime powder with 0.02 to 1 part by weight of an organopolysiloxane represented by the formula (=100 mol%). 2 As a compound of general formula (), R ¹ , R ² , and R ³ are each a methyl group, l = 2 to 35 mol%, m
Claim 1 using a methylpolysiloxane fluid in which n = 40 to 93 mol% and n = 5 to 25 mol%.
The method described in section. 3 General formula () for lime powder finer than 100 mesh
The method according to claim 1 or 2, wherein the treatment is carried out by adding the compound in a solvent-free state and mixing and stirring at room temperature to 100°C.