DE2534230C3 - Use of sulfur concrete for the production and lining of acid, alkali and solvent-resistant pipes and containers - Google Patents

Description

Sulfur concrete is a mixture of sulfur as a binding agent and a wide variety of aggregates Type As with normal concrete, natural heavy aggregates such as sand, gravel, gravel or crushed stone can be used and natural light aggregates such as pumice and tuff can be used. Also artificial heavy aggregates, such as slag or light aggregates such as slag sand, slag pumice, porous boiler slag, Brick chippings, expanded clay, perlite and the like can be used. Sulfur concretes are thereby prepared by cooling mixtures of the additives mentioned and molten sulfur leaves, whereby the mixtures solidify to products with concrete-like hardness,! m compared to cement concretes they offer advantages because they do not wait for 28 days, but rather a short time after they have solidified achieve their ultimate compressive and flexural strengths and because they are used again after being re-melted can be.

It is known that the cement binder in cement concrete is not acid-resistant. Hence all are acidic chemicals and their solutions aggressive to cement concrete. Likewise, all sulphate hookers do harm Waters with more than 300 mg SCVI. On the other hand, cement concrete is hardly affected by alkaline media attacked.

Ordinary sulfur concrete, in contrast, is somewhat acid-resistant, but sensitive to alkali.

According to a separate proposal, which does not belong to the state of the art, sulfur concretes with particularly high compressive and flexural strengths can be produced by mixing molten sulfur and dicyclopentadiene as a binder with aggregates and cooling the resulting mixture by adding sulfur, dicyclopentadiene and the aggregates at temperatures from 120 to 160 ° C mixed with each other, the duration for which sulfur and dicyclopentadiene act on each other at the selected temperature is set so that it is on a straight line parallel to the ordinate of the figure and intersecting the abscissa at the selected temperature , and is limited by the intersection of the straight line with curves A and D.

It was surprisingly found that the sulfur concrete produced by this process is opposite Sulfur concrete that has been manufactured using other methods and not dicyclopentadiene contains, not only increased acid resistance and increased resistance to salts and Has solvents, but is also extremely resistant to alkalis

For this reason, this sulfur concrete is suitable - the one made by mixing molten concrete Sulfur and dicyclopentadiene as binders with additives at temperatures of 120 to 160 ° C

ίο has been obtained, the duration in which sulfur and dicyclopentadiene have acted on each other at the selected temperature has been set so that it is limited to a straight line parallel to the ordinate of the figure and intersecting the abscissa at the selected temperature through the intersection of the straight line with the curves A and D, lies - for the production and lining of salt, acid, alkali and solvent-resistant pipes and containers.

The sulfur concrete is produced in such a way that 2 to 8 percent by weight are added to a sulfur melt, preferably 4 to 6 percent by weight, dicyclopentadiene and the two components in the associated temperature-dependent total reaction times to be taken from the figure react with one another leaves and brings in the additives within these reaction times. At the end of the response time the still hot and liquid mixture is then supplied to its intended use before solidification by salt, acid, alkali and solvent-resistant pipes, containers or the like are produced, or such lined with the enamel. But you can also proceed so that one in a first stage Mixture of sulfur and dicyclopentadiene produces, with only 80 to 95% in each Temperature required exposure time expends and in a second stage the obtained and but optionally also cooled, solidified and remelted mixture while observing the remaining exposure time mixed with the aggregates and then supplied to their intended use

The particular advantage of this procedure is that you can use the first and second process stage can carry out spatially and spatially separated from each other. So you can start with a mixture of the Produce binder in a production facility and then this mixture without significant stress store or transport from storage and transport room. The aggregates are only used on site mixed in. Of course, temperatures other than those in the first stage can also be used in the second stage comply if they are only within the specified range. If you choose a different temperature, so the remaining exposure time is extended or shortened according to this temperature.

Table 1 shows some points on the curve of curves A, D and curves B, C, which determine the preferred exposure times.

60 Table 1 (i; sum reaction time (h)
AWAY 15.00
6.00
3.30 C. D. temperature 11.00
4.70
2.35 23.00
11.50
6.00 29.00
14.40
8.00 65 120
125
130

continuation

Temperature total reaction time (h)
(C ") AB

135
140
145
150
155
160

1.25
0.70
0.43
0.27
0.18
0.12

1.80
1.05
0.67
0.44
0.31
0.22

3.40
2.15
1.40
0.95
0.67
0.50

4.70 2.90 1.90 1.35 1.00 0.75

Temperatures of 130 to 145 ° C. are preferably maintained in the process mentioned.

The following table 2 contains calculated erosion rates (mm / year) measured over four weeks Corrosion tests on sulfur concrete according to the method described above from 78 percent by weight Standard sand (DlN 1164) and 22 percent by weight binder made from 95 percent by weight sulfur and 5 Percentage by weight of dicyclopentadiene (designation: NS / SD 22) and of pure sulfur concrete made from 76

Weight percent norn sand and 24 weight percent Sulfur (designation: NS / S 24) or from 64 percent by weight standard sand and 36 percent by weight sulfur (Designation: NS / S 36). To carry out the experiments, two 1 × 2 × 11 cm prisms were used in each case For 4 weeks in the presence of air in aqueous solutions of the inorganic compounds listed in the table Compounds or stored in the organic solvents The salts, acids and bases were each in 3 concentrations used

Evaporated amounts of solvent were replaced. The symbol J. indicates that either no erosion or even a slight increase in weight (NaCl solutions!) Was found.

The sulfur concrete NS / SD 22 was produced as follows:

95 parts by weight of sulfur are liquid at a temperature of 135 ° C with 5 parts by weight Dicyclopentadiene mixed and left at this temperature for 135 minutes. The liquid binder is then poured onto 354.5 parts by weight of the same hot standard sand according to DIN 1164 and another 15 Mixed for minutes

Table 2 0.1 mol / l 1 Sulfur concretes Abrasion in (mm / year) at NS / S 36 1.0 mol / l NS / SD 22 NS / S 24 Chemical resistance data of 6. Lmol / l 0.02 Chemicals 0.02 0.28 0.01 0.78 after Bases 0, lmoi / l 0.10 total dissolution NaOH 1.0 mol / l 2.77 3 to 4 days 5.3 mol / l 0.02 0.1 mol / 1 0.04 0.05 1.0 mol / l 0.01 0.09 0.06 Acids 6.6 mol / l 0.03 0.13 0.02 HCl ./. 0.03 0.06 0.1 mol / 1 0.02 0.11 ./. 1.0 mol / 1 0.03 0.02 H ₂ SO ₄ 5.4 mol / l 0.02 0.02 1.9 mol / l 0.02 ./. Organic solvent 0.0 0.01 ./. Salts Methanol ./. 0.02 0.31 NaCl acetone ./. 0.36 Heavy fuel 0.04 0.02 Methylene chloric 0.06 0.06 Na ₃ SO ₃ toluene 0.03 0.18 0.85 Cyclohexane 0.09 1.01 2.72 0.54 5.35 4.32 1.80 6.92 4.90 2.38 11.35 2.58

The table shows the significantly better corrosion protection not only from the "more closed" surface of the

hold of the sulfur-modified sulfur concrete modified with dicyclopentadiene depends on, can be seen in the

Recognize felbetons NS / SD 22 in comparison to NS / S 24. Compare with NS / S 36. Here, too, is the corrosion rate

That the higher corrosion resistance is always greater than with the NS / SD 22. (Due to the good

The modified sulfur binding agent of the NS / SD 22 already wets the sand grains a smooth "closed" surface, while the surface of the NS / S 24 still appears "rough" and light is vulnerable. A smooth, "closed" surface is only achieved when using pure sulfur at 36 percent by weight sulfur.) The most serious difference in the corrosion behavior of the sulfur concretes consists in 20% NaOH (6.1 mol / l), while the pure sulfur concrete prisms completely after 3 to 4 days are destroyed, the prisms of the sulfur concrete reinforced with dicyclopentadiene only show after 4 weeks slight superficial burns.

The following are the results of annual weathering, soil storage and reinforcement tests reproduced from samples from NS / SD 22 and NS / S 24:

NS / SD 22 NS / S 24 Weathering 0.011 0.025 (Removal in mm / year) Floor storage 0.007 0.027 (Removal in mm / year) Reinforcement with construction no Cracking steel I (0 8 mm) destruction

For the one-year weathering test, four 7-cm test cubes were produced and outdoors stored. For the soil storage test, eight 1 × 5 × 10 cm plates were produced in each case and buried 10 cm deep in garden soil. The average erosion rates again confirm that greater corrosion resistance of the sulfur concrete reinforced with dicyclopentadiene.

For practical use, it is possible to reinforce or connect a building material with steel important. Therefore, four 7 cm cubes were provided with embedded or protruding steel rods. They were stored in a concentrated NaCl solution for 8 days in order to initiate steel corrosion and then exposed to the elements for a year. All four sulfur concrete cubes made from NS / S 24 were through Rusting underneath and the resulting cracking destroyed. All four sulfur concrete cubes were made from NS / SD 22 completely unchanged.

These results show the superiority of the method and use specified Sulfur concrete made from dicyclopentadiene compared to that made by conventional methods Sulfur concrete with regard to its resistance to solvents, salts, acids and, in particular, alkali. Because of this superiority, the sulfur concrete made using dicyclopentadiene is suitable for the production of salt, acid, alkali and chemical resistant pipes, containers and the like or also for the lining of pipes and containers.

1 sheet of drawings

Claims (1)

Claim: Use of sulfur concrete - which has been obtained by mixing molten sulfur and dicyclopentadiene as a binder with additives at temperatures of 120 to 160 ^° C., the duration for which sulfur and dicyclopentadiene acted on each other at the selected temperature has been set in this way that it lies on a straight line parallel to the ordinate of the figure, which intersects the abscissa at the selected temperature, limited by the intersection of the straight line with the curves A and D (see drawing) - for the production and lining of salt, acid, alkali and solvent-resistant pipes and containers.