DE1558124C - Binder for foundry mold sand - Google Patents

Description

3 Compressive strength
kg / cm ² permeability 4th Rest
humidity
% 15 to 21
2 to 4
5 to 10 500 to 1000
500 to 1500
400 to 800 surfaces
stability
index
7o 3.1
3.1
3.2 Pulp process 89 to 94
85 to 90
87 to 91 Casting process Treatment according to the pouring method

Herein the word means surface stability index :

Original sample weight - reduction
Original sample weight

The treatment that is carried out after the pouring process is physical Treatment, e.g. Compression and chemical treatment, d. H. Addition of an implementation participant.

A comparison with known cement or cement-molasses forms shows the advantage that one larger Can produce castability. Furthermore, the setting of the curing time is possible by selecting the type of Activator and the amount of activator added.

At a temperature of 700 to 1000 ⁰ C, an excellent mechanical value which is the same as for oil sand is obtained.

Furthermore, the setting of the binder is easy. In particular, it is possible to adjust the pH.

The good properties of the spongy binding agent and the foundry sapde can be used in the long term are maintained, and bringing the pH to an alkaline range results immediately to hydraulic hardening.

Better results are also achieved with regard to the long-lasting mechanical strength compared to cement forms and cement molasses molds.

Finally, it is also possible to make the sand flowable with relatively little moisture.

Generally speaking, blast furnace slag and pozzolan are better settling materials and show excellent properties, so that the properties as Foundry sand binders can be adjusted relatively easily.

Claims (1)

1 2 but small, so the scope when using this process is limited to small mold sizes. Palent claim: _{must remain} _ The invention is based on the object Use of latent hydraulic high-5 binders for foundry sand with substantially verofschlage or pozzolan with a particle-improved properties, in particular substantially shorter size of 1 to 100 μm, which by the addition of zerer hardening time to propose.
3 are activated to 8 ° / _o aqueous caustic alkalis, when the solution of this object by the invention Binder for foundry molding sand. consists in the use of latent hydraulic ίο Blast furnace slag or pozzolan with a particle size from 1 to 100 μηι, which by adding 3 to 8% caustic alkalis are activated as binders - ^ - ^: for foundry molding sand. This is the hardening time significantly shortened and also adjustable. . . 15 It is also possible to use the sand with proportionately to get a little liquid to flow. Since the It is common practice to act as a binder for foundry liquor in a certain sense as a coating on the sand molding compounds Acid blast furnace slag to use form forms, it is extraordinarily easy to use the form (see German patent specification 739 157). Those currently being replaced, and follow-up treatment is essential cement molds used show 20 relieved. but a number of disadvantages, in particular it is also possible to add the material with the hardening speed is slow, and water can also be kept liquid without the activator sufficient moisture is required. After being attached. Of course it is also important Addition of this moisture makes it difficult that blast furnace slag and pozzolan cement cheap Control hardships. When transporting the sand mixture 25 are binding materials. Using the through a pipe measures must be taken, binder according to the invention can both after about caking of the pulping process known with this binding agent as well as after to prevent mixed sand on the pipe, e.g. B. the known. the pipe needs to be washed. Further advantages and details of the invention Also revealed a sudden deterioration of some examples of use, wherein either the mechanical properties results from an Trocknungstem- 30 become apparent from the following description, temperature of 150 ⁰ C. The ramming or pouring process is used The use of latent has also become further:
hydraulic binders made from blast furnace slag or pozzolan has been proposed in construction, 35 mass 1 which is activated by the addition of alkaline substances (see Fritz Keil, Hochofenschlacke, Verlag Stahl und Eisen mbH). According to this reference, quartz sand 100 but has the production of cement from dry blast furnace slag 10 granulated or slowly solidified in air 40 ₈ % aqueous solution sodium hydroxide ... 6
Slag with 10 to 30% incinerated unquenched Lime has not found its way into the practice. For this ^casting:; is, among other things, the risk of drifting at the Use of larger quantities of unslaked lime, quartz sand 100 specified. Stronger bases like caustic soda and caustic potash. 45 blast furnace slag 10 as well as other known basic salts such as g _{0 / aqueous} sodium hydroxide solution .. 6
Likewise, soda is only available from laboratory, '..,,. ·., · ", _Λ -, try used as a stimulator and not £ 0 at the surfactant Cement manufacture. This is due, among other things, to ' that one fears the easy solubility of alkalis, 50 ", the blooming among other things inducing mass can give. _ Ramming process and casting process
Caustic soda and caustic potash also draw water from the air and settle with the air carbon quartz sand (silicon dioxide grain) 100 acid to carbonate to _s so that the thus prepared 55 Blast furnace slag 10 Binders would not be sufficiently stable in storage. Thus calcium hydroxide 1 this prior art shows that the use of sodium hydroxide solution, 8 »/«, aqueous .. 6.5 of latent hydrauhschen binders from blast furnace, __,, · .- ■,. ',.;, _n 1 slag or pozzolan is disadvantageous and 0.3 in the surfactant Practice therefore does not apply. 60 Finally, a method of making Regarding the mass 2 are the corresponding Foundry molding masses known, with scratch sand, with physical values shown in the table, Lime mixed with the addition of caustic soda and which is available after 24 hours, After shaping at elevated temperature, the sand shows if there is fluidity is consolidated. However, this procedure shows the mechanical strength values according to the table, Part that here too the rate of hardening is very The comparison of the compressive strength values obtained in this way is low, so that one endeavors to show the hardening time that the pulping process leads to better values Decrease heating. The strength of form is leads.