METHOD FOR PRODUCING A MOULDING MATERIAL MIXTURE AND A MOULDED BODY THEREOF IN THE CASTING INDUSTRY AND KIT FOR USE IN THIS METHOD

• US 20200130049A1
• Filed: 06/28/2018
• Published: 04/30/2020
• Est. Priority Date: 06/30/2017
• Status: Active Grant

• Current Assignee: Huttenes-Albertus Chemische Werke GmbH
• Original Assignee: Huttenes-Albertus Chemische Werke GmbH
• Inventors: LUSTIG, Christian, BALDY, Marcin, MULLER, Edgar, REINOLD, Lukas Mirko, ANDERTEN, Sabrina Maria, SCHWEINEFUss, Maria, VARGOVIC, Rene
• Granted Patent: US 10,981,215 B2
• Time in Patent Office: Days
• CPC Class Codes: B22C 1/18 of inorganic agents B22C1/162 takes precedence
• CPC Class Codes: B22C 1/186 contaming ammonium or metal silicates, silica sols
• CPC Class Codes: B22C 1/188 Alkali metal silicates

Abstract

A description is given of a method for producing a molding material mixture or for producing a molding material mixture and a molding therefrom, preferably casting molds or cores, for use in the foundry industry, where the molding material mixture comprises a mold base material and a solution or dispersion comprising lithium-containing waterglass, comprising the following steps: (1) producing or providing a kit at least comprising as separate components: (K1) an aqueous solution or dispersion comprising waterglass and (K2a) a first waterglass-free solution or dispersion comprising lithium ions in solution in water, and also preferably (K2b) a second waterglass-free solution or dispersion, preferably o comprising lithium ions in solution in water with a lower concentration than in component (K2a), and thereafter (2) producing a mixture of the mold base material with a fraction of component (K1) and with a fraction of component (K2a), and also optionally with a fraction of component (K2b). Further described is an aforementioned kit, more particularly for application in the method of the invention. An installation is specified as well for producing an intermediate solution or dispersion, comprising lithium-containing waterglass, for use in producing a molding material mixture or for producing a molding material mixture and a molding therefrom.

Claims

1. A method for producing a molding material mixture or for producing a molding material mixture and a molding therefrom, where the molding material mixture comprises:

(M1) a mold base material, and

(M2) a solution or dispersion comprising lithium-containing waterglass, which possesses a molar Si02/M20 modulus in the range from 1.6 to 3.5, and in which the molar fraction of the Li20 within M20 is in the range from 0.05 to 0,60, comprising the following steps;

(1) producing or providing a kit at least comprising the following separate components;

(K1) an aqueous solution or dispersion comprising waterglass, where the SiO₂ content is in the range from 20 to 34 wt %, based on the total mass of the solution or dispersion, and/or where the molar SiO₂/M₂O modulus is greater than the molar modulus of the lithium-containing waterglass in the molding material mixture being produced, and

(K2a) a first waterglass-free solution or dispersion comprising lithium ions in solution in water, where

the concentration of the lithium ions is in the range from 0.3 to 5.3 mol/Lcand

the total concentration of the lithium, sodium and potassium ions is in the range from 0.3 to 28.0 mol/L, and thereafter

(2) producing a mixture of the mold base material (M1) with a fraction of component (K1) and also with a fraction of component (K2a), where the solution or dispersion (M2) is formed by mixing together the components of the kit that are used, where M20 denotes in each case the total amount of lithium oxide, sodium oxide and potassium oxide.

2. The method as claimed in claim 1 for producing a molding material mixture and a molding therefrom, wherein the kit produced or provided in step (1) additionally comprises the following separate component:

(K2b) a second waterglass-free solution or dispersion comprising alkali metal ions in solution in water, where the concentration of the lithium ions is lower than in component (K2a), and

the total concentration of the lithium, sodium and potassium ions is in the range from 0.3 to 28.0 mol/L, and

preferably the total concentration of the lithium, sodium and potassium ions of component (K2b) differs by not more than 20%, preferably by not more than 10%, from the total concentration of the lithium, sodium and potassium ions in component (K2a), and

wherein step (2) comprises the following;

(2) producing a mixture of the mold base material (M1) with a fraction of component (K1) and also with a fraction of component (K2a) and optionally a fraction of component (K2b), where the solution or dispersion (M2) is formed by mixing together the components of the kit that are used.

3. The method as claimed in claim 1, where the molding material mixture comprises:

(M1) a mold base material, and

(M2) a solution or dispersion comprising lithium-containing waterglass, which possesses a molar SiO₂/M₂O modulus in the range from 1.6 to 3.5, and

in which the molar fraction of the Li₂O within M₂O is in the range from 0.05 to 0.60, comprising the following steps;

(1) producing or providing a kit at least comprising the following separate components;

(K1) an aqueous solution or dispersion comprising waterglass, where the SiO₂ content is in the range from 20 to 34 wt %, based on the total mass of the solution or dispersion, and/or where the molar SiO₂/M₂O modulus is greater than the molar modulus of the lithium-containing waterglass in the molding material mixture being produced,

(K2a) a first waterglass-free solution or dispersion comprising lithium ions in solution in water, where

the concentration of the lithium ions is in the range from 0.3 to 5.3 mol/L, and

the total concentration of the lithium, sodium and potassium ions is in the range from 0.3 to 28.0 mol/L, and

(K2b) a second waterglass-free solution or dispersion comprising lithium ions in solution in water, where

the concentration of the lithium ions is lower than in component (K2a) and is in the range from 0.1 to 5.0 mol/L, and

the total concentration of the lithium, sodium and potassium ions is in the range from 0.3 to 28.0 mol/L, and

the total concentration of the lithium, sodium and potassium ions differs by not more than 20%, from the total concentration of the lithium, sodium and potassium ions in component (K2a),—

and thereafter

(2) producing a mixture of the mold base material (M1) with a fraction of component (K1) and also with a fraction of component (K2a) and with a fraction of component (K2b), where the solution or dispersion (M2) is formed by mixing together the components of the kit that are used,

where M₂O denotes in each case the total amount of lithium oxide, sodium oxide and potassium oxide.

4. The method as claimed in claim 1 for producing a molding material mixture and a molding therefrom, comprising the additional steps of

establishing, determining or estimating one or more parameters selected from the group consisting of ambient temperature during the production of the molding, relative humidity during the production of the molding, temperature during the storage of the molding, relative humidity during the storage of the molding, absolute humidity during the production of the molding, absolute humidity during the storage of the molding, and storage duration of the molding, and

controlling the fractions to be used of components (K2a) and (K2b) as a function of the established, determined or estimated parameter or parameters selected from the group consisting of ambient temperature during the production of the molding, relative humidity during the production of the molding, temperature during the storage of the molding, relative humidity during the storage of the molding, absolute humidity during the production of the molding, absolute humidity during the storage of the molding, and storage duration of the molding, and/or

where the method is embodied as at least partial serial fabrication of a number of moldings, where, in the case of increase or expected increase in one or more parameters selected from the group consisting of ambient temperature during the production of the molding, relative humidity during the production of the molding, temperature during the storage of the molding, relative humidity during the storage of the molding, absolute humidity during the production of the molding, absolute humidity during the storage of the molding, and storage duration of the molding,

the fractions that are used of component (K2a) are increased for the fabrication of the moldings and/or

the molar fraction of the Li₂O within M₂O in the solution or dispersion (M2) is increased for the fabrication of the moldings.

5. The method as claimed in claim 3, where, for establishing, determining or estimating the one or more parameters selected from the group consisting of ambient temperature during the production of the molding, relative humidity during the production of the molding, temperature during the storage of the molding, relative humidity during the storage of the molding, absolute humidity during the production of the molding, absolute humidity during the storage of the molding, and storage duration of the molding, a data capture facility or data processing facility is provided, and

to control the fractions that are to be used of components (K2a) and (K2b) as a function of the established, determined or estimated parameter or parameters, a control facility is provided, where, between the data capture facility or the data processing facility and the control facility, a data connection is set up to transfer parameter data.

6. The method as claimed in claim 1, where, during production of the molding material mixture, one or more constituents are additionally added which are selected from the group consisting of:

(M3) particulate, amorphous silicon dioxide;

barium sulfate;

carbohydrates;

phosphorus compounds;

surface-active compounds;

oxidic boron compounds;

metal oxides;

lubricants, esters and release agents.

7. The method as claimed in claim 1, where the first waterglass-free solution or dispersion (K2a) and optionally the second waterglass-free solution or dispersion (K2b) in each case comprise lithium hydroxide in solution in water.

8. The method as claimed in claim 2, where

the aqueous solution or dispersion comprising waterglass (K1) has a pH in the range from 10.0 to 13.0, and/or

the first waterglass-free solution or dispersion comprising lithium ions in solution in water (K2a) has a pH in the range from 8.0 to 14.0, and/or

the second waterglass-free solution or dispersion comprising lithium ions in solution in water (K2b) has a pH in the range from 8.0 to 14.0.

9. The method as claimed in claim 1, where in step (2) first, in the absence of the mold base material, a solution or dispersion (M2) is formed by mixing together the components of the kit that is used, and thereafter a mixture of the or a fraction of the mold base material (M1) with a fraction or the total amount of the resulting solution or dispersion (M2) is formed and/or

where the solution or dispersion (M2) produced, before the forming of the mixture with the mold base material (M1), contains no visible precipitates or gel fractions.

10. The method as claimed in claim 9, where the components of the kit that are used are mixed together to form the solution or dispersion (M2) in a mixing facility, where the mixing facility is a metering vessel or a mixing pipe.

11. The method as claimed in claim 9, where the fraction or the total amount of the solution or dispersion (M2) formed, before the forming of a mixture with the or a fraction of the mold base material (M1), is stored for a period of not more than 7 days in the mixing facility.

16. An installation for use in producing a molding material mixture or for producing a molding material mixture and a molding therefrom,

where the installation at least comprises:

a first storage tank (Z1), containing as first component an aqueous solution or dispersion (K1) comprising waterglass, where the SiO₂ content is in the range from 20 to 34 wt %, based on the total mass of the solution or dispersion, and/or where the molar SiO₂/M₂O modulus is greater than the molar modulus of the lithium-containing waterglass in the molding material mixture under production,

a second storage tank (Z2), containing as second component a first waterglass-free solution or dispersion (K2a), comprising lithium ions in solution in water, where

the concentration of the lithium ions is in the range from 0.3 to 5.3 mol/L, and

the total concentration of the lithium, sodium and potassium ions is in the range from 0.3 to 28.0 mol/L,

a mixing facility (Z3), for mixing at least the first and the second components to produce an intermediate solution or dispersion, and

where at least the first and the second storage tanks (Z1, Z2) are connected to the mixing facility (Z3) in each case by one or more lines (Z4),

where M₂O denotes in each case the total amount of lithium oxide, sodium oxide and potassium oxide, and/or

where the lithium-containing waterglass in the intermediate solution or dispersion possesses a molar SiO2/M20 modulus in the range from 1.6 to 3.5 and/or in which the molar fraction of the Li₂O within M₂O is in the range from 0.05 to 0.60, where M₂O denotes in each case the total amount of lithium oxide, sodium oxide and potassium oxide, and/or

where the use takes place in a method as claimed in claim 1.

17. The installation as claimed in claim 16, further comprising a third storage tank (Z5), containing a second waterglass-free solution or dispersion (K2b) comprising alkali metal ions in solution in water, where

the concentration of the lithium ions is lower than in component (K2a) and is in the range from 0 to 5.0 mol/L, and

the total concentration of the lithium, sodium and potassium ions is in the range from 0.3 to 28.0 mol/L, and

the total concentration of the lithium, sodium and potassium ions differs by not more than 20%, from the total concentration of the lithium, sodium and potassium ions in component (K2a),

where the mixing facility (Z3) is embodied for mixing at least the first, second and third components, to produce the intermediate solution or dispersion, and

where at least the first, the second and the third storage tank are connected to the mixing facility (Z3) in each case by one or more lines (Z4).

12. A kit for producing a solution or dispersion comprising lithium-containing waterglass, at least comprising the following separate components:

(K1) an aqueous solution or dispersion comprising waterglass, where the SiO₂ content is in the range from 20 to 34 wt %, based on the total mass of the solution or dispersion, and/or where the molar SiO₂/M₂O modulus is greater than the molar modulus of the lithium-containing waterglass being produced, and

(K2a) a first waterglass-free solution or dispersion comprising lithium ions in solution in water, where

the concentration of the lithium ions is in the range from 0.3 to 5.3 mol/L, and

the total concentration of the lithium, sodium and potassium ions is in the range from 0.3 to 28.0 mol/L.

13. The kit as claimed in claim 12, additionally comprising as a further separate component

(K2b) a second waterglass-free solution or dispersion comprising alkali metal ions in solution in water, where the concentration of the lithium ions is lower than in component (K2a) and is in the range from 0 to 5.0 mol/L, and

the total concentration of the lithium, sodium and potassium ions is in the range from 0.3 to 28.0 mol L, and

the total concentration of the lithium, sodium and potassium ions differs by not more than 20% from the total concentration of the lithium, sodium and potassium ions in component (K2a).

14. The kit as claimed in claim 12 for producing a solution or dispersion comprising lithium-containing waterglass, at least comprising the following separate components:

(K1) an aqueous solution or dispersion comprising waterglass, where the SiO₂ content is in the range from 20 to 34 wt %, based on the total mass of the solution or dispersion, and/or where the molar SiO₂/M₂O modulus is greater than the molar modulus of the lithium-containing waterglass under production,

(K2a) a first waterglass-free solution or dispersion comprising lithium ions in solution in water, where

the concentration of the lithium ions is in the range from 0.3 to 5.3 mol/L, and

the total concentration of the lithium, sodium and potassium ions is in the range from 0.3 to 28.0 mol/L, and

(K2b) a second waterglass-free solution or dispersion comprising lithium ions in solution in water, where, the concentration of the lithium ions is lower than in component (K2a) and is preferably in the range from 0.1 to 5.0 mol/L, more preferably in the range from 0.1 to 2.0 mol/L, and

the total concentration of the lithium, sodium and potassium ions is in the range from 0.3 to 28.0 mol/L, and

the total concentration of the lithium, sodium and potassium ions differs by not more than 20% from the total concentration of the lithium, sodium and potassium ions in component (K2a).

15. A method of producing a molding material mixture or for producing a molding material mixture and a molding therefrom, comprising providing a kit as claimed in claim 12. where the molding material mixture comprises:

(M1) a mold base material, and

(M2) a solution or dispersion comprising lithium-containing waterglass, which possesses a molar SiO₂/M₂O modulus in the range from 1.6 to 3.5, and in which the molar fraction of the Li₂O within M₂O is in the range from 0.05 to 0.60.