DE3616168A1 - Magnesium phosphinates and calcium phosphinates and basic refractory raw materials bound therewith - Google Patents

Abstract

Magnesium and calcium salts of phosphinic acids of the general formula <IMAGE> in which R<1> and R<2> denote different or identical functional groups, and their preparation are described. These phosphinates are outstandingly suitable as binders in basic refractory raw materials such as magnesium oxide, calcium oxide, dolomite, olivine, forsterite and mixtures thereof.

Description

For the chemical bonding of inert, silicic acid and Raw materials containing aluminum oxide can contain acidic phosphate binders such as phosphoric acid, monoaluminum phosphate, etc. be used.

Because of the spontaneous reaction of such acidic binders the raw materials this is with basic refractory materials not possible. Ideally suited chemical binders for basic refractory raw materials such as magnesium oxide, olivine etc. are still unknown. One uses for the production chemically bound refractory stones and masses basic raw materials mainly binders such as water glasses and alkali polyphosphates.

The difficulties can be overcome with these binders overcome to some extent, but such are processing-friendly produced mixtures can only be stored for a short time, or reduce the strength of the stones made with it changes considerably with increasing storage time.

Another, not negligible disadvantage of this Binder lies in the content of alkali oxide. This Alkali content acts as a in these refractory building materials Flux and sets the fire resistance of these building materials  down. Due to the early appearance of glass phases relatively low application temperatures will also Resistance to thermal shock of such building materials is reduced.

There has been no shortage of attempts, chemical binders for basic raw materials that procure this Do not have disadvantages. So far, such a binder but did not become known.

The present invention now describes such chemical Binder, d. H. alkali-free products normal ambient temperatures only slowly with basic Refractory raw materials react and adequate binding results exhibit.

When developing this product, we are from Considered that such a binder is water soluble must be stable in an alkaline medium and has film-forming properties, so sufficiently high Green strength can be achieved. The binder should moreover when increasing the temperature with the basic React raw materials and when exposed to temperature neither toxic nor otherwise harmful decomposition products form.

It has now been found that neutral and basic magnesium and calcium salts of phosphinic acids have excellent binding properties for basic refractory raw materials.

The present invention describes magnesium and Calcium salts of phosphinic acid of the general formula

in which R ₁ and R ² are H, CH ₃ , C ₂ H ₅ , HOCH ₂ , HOC ₂ H ₄ , HOC ₃ H ₆ , CH ₂ COOH and CH (OH) COOH.
R ¹ and R ² can both match and have different meanings.

The magnesium and calcium phosphinates are obtained from Neutralize solutions of the corresponding phosphinic acids with aqueous slurries of magnesium or Calcium hydroxide or magnesium or calcium oxide and Concentrate by evaporating the water at normal or negative pressure. For neutralization it is advisable To maintain reaction temperatures around 50 ° C to implement to be able to carry out sufficiently quickly.

Another object of this invention are with addition of these magnesium and calcium phosphinates Refractory materials. Such refractory materials are: Magnesium oxide, calcium oxide, dolomite, olivine and forsterite or their mixtures.

Example 1:

88 g of 75% hypophosphorous acid and 170 g of 37% Formaldehyde is heated to 50 ° C. for 30 minutes with stirring. Then gradually increase the temperature to 80 ° and holds at this temperature for 2 h. In vacuum, on the Half concentrated, with excess formaldehyde Will get removed. Then neutralize with cooling and vigorous stirring by adding about 20 g of magnesium oxide. If necessary, the solution is activated carbon decolorized, filtered and concentrated in vacuo, the Magnesium hydroxymethylphosphinate deposits as a white powder. After drying in vacuum it shows the following Analysis values:

C: 17.7%, Mg: 8.9%, P: 22.9%  

Example 2:

The procedure is analogous to Example 1, but neutralized with 29 g calcium hydroxide, so you get the calcium salt Bis- (hydroxymethyl) -phosphinic acid, the following analysis shows:

C: 16.2%, Ca: 14.0%, P: 21.2%

Example 3:

81 g of methylphosphonous acid are dissolved in 50 ml of water and with 165 g of 37% formalin with stirring and cooling transferred. The temperature is gradually increased to 75 ° C and holds at this temperature for 3 hours. Then proceed as in Example 1.

Analysis: C: 19.6%, Mg: 10.3%, P: 25.2%

Example 4:

93 g of dimethylphosphinic acid are dissolved in 80 ml of water and carefully by adding 29 g of magnesium hydroxide neutralized. After working up according to Example 1, one obtains a white powder of the following composition:

C: 23.0%, Mg: 11.2%, P: 29.7%

Example 5:

From dimethylphosphinic acid and milk of lime one obtains in analogous procedure to Example 4 calcium dimethylphosphinate.  

Example 6:

123 g of hydroxyethyl-methyl-phosphinic acid result in neutralization with 29 g magnesium hydroxide after drying the magnesium phosphinate with the following composition:

C: 27.6%, Mg: 9.2%, P: 23.6%

Example 7:

88 g of 75% hypophosphonic acid become 37% with 85 g Formalin solution kept at 50 ° C for 2 h and then Heated to 75 ° C for 20 min. Allow to cool, mixed with 150 g glyoxylic acid (50%) and holds again at 75 ° C for 2 h. After neutralization with magnesium oxide is activated carbon discolored and concentrated. The dry reaction product has the following composition:

C: 18.3%, Mg: 12.3%, P: 15.8%

Example 8: (Comparative example)

The following mix for a ramming paste is made and mixed from a commercially available China sintered magnesia:
65% by weight grit 1-3 mm;
10% by weight grain size 0-1 mm;
23% by weight flour DIN 70 and
2% by weight of refractory clay DIN 70.

2% by weight are added to the dry premixed raw material mixture given powdered Na polyphosphate and after homogenization the mixture so much water that the total moisture Is 5%. This ramming mass is used on the Ram test specimen of von 50 mm × 50 mm. The compression is carried out by 10 blows on both sides. The result of the tests of these test specimens is in the the following tables 1-3.  

Example 9:

The same mix of Chinese sintered magnesia as described in Example 1 is mixed with 2.5% magnesium salt of dimethylolphosphinic acid (according to Example 1) instead of Na polyphosphate, brought to a total moisture content of 5% with water and added as described in Example 1 Test specimens processed.
Here, too, the test results are contained in Tables 1-3 below.

Example 10:

In this example, the following are described under 1 and 2 Working method from China-Magnesia sinter test specimen made, but using 3.5% magnesium salt of dimethylolphosphinic acid (according to Example 1).

Example 11:

A molding compound with a total moisture of 3% is produced from the same raw materials and according to the same procedure as described in Example 8. The test specimens (⌀ 50 mm × h 50 mm) are produced from this mass on a laboratory press with a pressing pressure of 50 N / mm ² .
Tables 1-3 contain the result of the tests carried out.

Example 12:

In this example too, the molding compound is produced with the raw materials and, according to the procedure of Example 9, with a total moisture of 3% and processed to test specimens on the laboratory press with a pressing pressure of 50 N / mm ² . The test results are also contained in Tab. 1-3.

Table 1

Cold compressive strength of ramming masses and stones from China sintered magnesia N / mm ²

Table 2

Pressure softening of ramming masses from China sintered magnesia

Load 0.05 N / mm ² - not prebaked

Table 3

Strength of test specimens made of sintered magnesia after storage of the finished mass before test specimen production

Example 13 (comparative example)

The following grain fractions of a commercially available Korea sintered magnesia were premixed in a laboratory compulsory mixer:
65% by weight grit 1-3 mm,
23% by weight flour DIN 70 and
10% by weight grain size 0-1 mm,
2% by weight of refractory clay.

2% by weight of powder was added to this dry mixture Given Na polyphosphate, homogenized and then by addition a tamped mass is produced from 7% water. From this Ramming mass were made by compression on the test specimen Fischer ram with 2 × 10 strokes, shaped on both sides. The test results of these test specimens are in the Tables 4-6 included.

Example 14:

Test specimens were produced using the same procedure as described in Example 13 and using the same raw materials. Instead of Na polyphosphate, however, 2.5% magnesium salt of methyl hydroxymethylphosphinic acid was used as the binder.
The test results for this example can also be found in Tables 4-6.

Example 15:

This example corresponds in all details to Example 14 above, but this time 3.5% magnesium salt of methyl hydroxymethylphosphinic acid was used as the binder.
The results of the tests can be found in Tables 4-6.

Table 4

Cold compressive strengths of ramming compounds from Korea sintered magnesia N / mm ²

Table 5

Pressure softening of ramming masses from Korea sintered magnesia

Load 0.05 N / mm ² - not prebaked

Table 6

Strengths of test specimens from Korea sintered magnesia after storage of the finished mass before test specimen production

Example 16 (comparative example)

From a pure, high-quality sintered magnesia (sea water), a ramming mass offset from the following grain fractions was mixed:
60% by weight grit 1-6 mm, 15% by weight grit 0-1 mm,
25% by weight flour DIN 70.

This dry raw material mixture became 2% by weight in powder form Na polyphosphate added and mixed homogeneously. A tamped mass was produced by adding 4% water, formed from the test specimen on the Fischer ram were. The compression was carried out by 10 blows on both sides, performed.

Example 17:

In the same way and with the same raw material as described in Example 16, a ramming mass was prepared and processed into test specimens. As a binder was only 2.5% magnesium salt of a mixture  Dimethylolphosphinic acid, dimethylphosphinic acid and Hydroxyethyl methyl phosphinic acid instead of alkali polyphosphate used.

Example 18:

Corresponds in full to Example 17, except for the Amount of binder, which was 3.5% in this example.

Example 19:

This example corresponds to Example 16 with the difference that the total moisture was only 3% and the test specimens were formed on a laboratory press with a compression of 50 N / mm ² .

Example 20:

This example corresponds in all to example 17, but here too only 3% total moisture was used and the test specimens were produced on a laboratory press with a pressure of 50 N / mm ² .

The test results for these examples can be found in tables 7 and 8.  

Table 7

Cold compressive strength of ramming masses and stones made of magnesia sinter N / mm ²

Table 8

Pressure softening of ramming masses from magnesia sinter

Load 0.05 N / mm ² - not prebaked

Example 21 (comparative example)

This is the production of a ramming mass from Norwegian olivine. In this case, the batch was mixed from the following raw materials and grits:
80% by weight olivine grain size 0-3 mm,
20% by weight magnesia sinter (Korea) 0-0.5 mm.

The mixture was mixed with 2 wt.% Na polyphosphate and moistened with 5% water.
The test specimens were compacted on the Fischer ram with 2 × 10 blows on both sides.

Example 22:

Corresponds to this except for the addition of Na polyphosphate Example 21. Instead of Na polyphosphate, 2.5% Ca salt of methylhydroxymethylphosphinic acid used.

Find the test results for these two examples in Tables 9 and 10.

In an analogous way, the magnesium or calcium salts the other claimed phosphinic acids are used, with similar results.  

Table 9

Cold compressive strength of ramming compounds from Norway. Olivine N / mm ²

Table 10

Pressure softening of ramming compounds from Norway. Olivine

Load 0.05 N / mm ² - not prebaked

Claims (2)

1) Magnesium and calcium salts of phosphinic acids of the general formula in which R ¹ and R ² are H, CH ₃ , C ₂ H ₅ , HOCH ₂ , HOC ₂ H ₄ , HOC ₃ H ₆ , CH ₂ COOH and CH (OH) COOH.
R ¹ and R ² can both match and have different meanings. 2) Basic refractory raw materials consisting of Magnesium oxide, calcium oxide, dolomite, olivine, forsterite or their mixtures, characterized in that that they are magnesium and Calcium phosphinates according to claim 1) in amounts of 0.3 to 5% included.