Process for preparing an additive for a binder or a construction material, additive for a binder or a construction material, and use of a mixture of slate and desert sand as an additive for a binder or a construction material

Abstract

The invention relates to a process for preparing an additive for a binder or a construction material, the process being intended to comprise the following steps: - grinding a mixture containing slate and desert sand.

Description

[0001] Process for producing an additive for a binder or a building material, additive for a binder or a building material and use of a mixture of slate and desert sand as an additive for a binder or a building material

[0002] Technical area

[0003] The invention relates to a method for producing an additive for a binder or a building material, an additive for a binder or a building material and a use of a mixture of slate and desert sand as an additive for a binder or a building material.

[0004] State of the art

[0005] The use of sand, particularly for the production of building materials, has already been discussed in the state of the art. Such processes are often complex, costly, and energy-intensive, and rely on toxic binders or other problematic additives.

[0006] In some cases, desert sand could not be used as a component of building materials without reducing the quality, resilience and durability of the building material.

[0007] Object of the invention

[0008] The object of the present invention is to overcome the disadvantages of the prior art.

[0009] Solution to the task

[0010] The subject matter of the independent claims leads to the solution of the problem. Advantageous embodiments are described in the subclaims.

[0011] A process for producing an additive for a binder or a building material, the process comprising the following steps:

[0012] - Grinding a mixture containing slate and desert sand.

[0013] Grinding can be done in a suitable grinding device.

[0014] As described below, the process particularly preferably involves the production of an additive for a building material.

[0015] Grinding can be carried out by adding the slate and desert sand to the grinding device, i.e., a mill or similar, simultaneously and together. Alternatively, it can be considered to add the slate to the grinding device first and add the desert sand at a later time. The slate can, for example, be in the form of crushed stone, chippings, grit, sand, or flour, with a coarse grain such as crushed stone, chippings, or grit being preferred. It can also be considered that the slate to be ground is in particles that are larger than chippings and gravel, or that the slate to be ground is not in particulate form. If the slate is ground before the desert sand is added, slate particles such as gravel that are no more than several orders of magnitude larger than the desert sand particles may already be present at the time the desert sand is added, which can simplify grinding.

[0016] Alternatively, you could consider grinding the desert sand first and adding the slate later.

[0017] In all embodiments, however, slate and desert sand are preferably ground together over a certain period of time.

[0018] The mixture is preferably a bulk material.

[0019] The mixture can contain other components besides slate and desert sand. For example, organic substances can be added. For example, it might be considered to add sea sand in addition to desert sand. Sea sand naturally contains components of dead marine plants and animals, such as corals, which naturally contain carbon. Alternatively, it might be considered to add substances instead of organic substances that at least contain a significant amount of carbon, even if they are not chemically organic.

[0020] According to a preferred embodiment, the mixture may consist of shale, desert sand, and sea sand. According to another embodiment, the mixture may consist of shale, desert sand, and a carbon source.

[0021] According to one embodiment, it can also be considered that the mixture consists of slate and desert sand, and thus does not comprise any further components besides the two components mentioned above.

[0022] Preferably, the mixture does not contain a binder, which would cause the components of the mixture to stick together or clump together. This does not preclude the use of the mixture as a component of a binder such as cement. The mixture is preferably used in cement or the like to later become a component of a building material to which the cement or the like has been added as a binder.

[0023] The mixture according to the embodiments of the present invention is therefore particularly preferably used in building materials.

[0024] Such a building material can comprise, in addition to the above-described mixture comprising jointly ground slate and desert sand, at least one aggregate and at least one binder. For example, concrete can be considered which, in addition to the above-described mixture, comprises an aggregate commonly used in concrete production and cement as a binder. The building material, in particular concrete, can comprise further components intended, for example, to improve its properties. However, it is also possible for the building material, in particular concrete, to consist of the above-described mixture, an aggregate, and a binder, for example, cement, and thus comprise no further components.

[0025] Because the process for producing the additive according to the aforementioned embodiments only comprises grinding the described components, but no further steps such as producing larger particles from the ground components, the process is particularly simple to carry out, environmentally friendly, and inexpensive. These advantages are also achieved by the fact that no toxic binders are used, which would cause the above-described jointly ground components to stick together, clump, or the like.

[0026] Desert sand usually consists predominantly of silicon dioxide. When ground with slate, changes occur on the surfaces of the slate particles and the desert sand particles. According to one example, slate has an alkaline effect. During or after grinding, silicate compounds can form. This occurs either due to the alkaline effect of the slate, particularly its alkaline components, or by other means.

[0027] Additional or alternative surface modifications of the slate particles and / or the desert sand particles are conceivable. In general, such surface modifications can be both chemical and purely mechanical in nature. New bonds can be formed between atoms or molecules, or the surface texture, such as roughness or surface roughness, can be altered. In particular, an increase in roughness or surface roughness through grinding is possible, which improves the effect of the mixture in the concrete in that rough particles in a component made from the concrete, for example, ensure greater stability and load-bearing capacity because the cohesion of the components contained in the concrete is improved.

[0028] The comminution of slate and sand during the grinding process, as well as any resulting surface changes, make the mixture a beneficial additive for the production of binding agents, particularly for building materials such as cement, lime, pozzolan, concrete, plaster, or mortar. The mixture is particularly preferred for use in building materials such as concrete, plaster, or mortar. The surface changes, such as increased roughness, and the silicate compounds forming on the surface can cause the mixture containing ground slate and desert sand to clump into larger particles after grinding, which can be beneficial for the setting of the building material in which the mixture is used. Such clumped particles can also improve the mechanical properties of the cured building material, i.e., a component made from the building material.However, even without such clumping, the mixture can have a beneficial effect on the properties of the building material and components made from it. It should be noted that in the past, it was often assumed that sand, and especially desert sand, was fundamentally unsuitable for the production of building materials due to its low roughness and very small grain size, as well as its grain size distribution without larger grains.

[0029] The increased surface area of ​​desert sand and slate caused by grinding can also cause basic components of the slate to react with the silicon dioxide in the desert sand to form silicate hydrates. This can occur during the setting process or during the post-curing process of a component made from the same material, such as concrete, which can sometimes take years. The grinding process exposes a larger surface area of ​​the desert sand and slate, allowing both the basic components of the slate and the silicon dioxide in the desert sand to interact more easily and frequently as reactants at their respective surfaces.

[0030] The proportion of slate and desert sand in the mixture can be at least 20% each.

[0031] The proportion of shale is at least 20%. It can be at least 30%, at least 40%, at least 50%, and up to 80%. The proportion of desert sand is at least 20%. It can be at least 30%, at least 40%, at least 50%, and up to 80%.

[0032] For example, the mixture can consist of 20% slate and 80% desert sand. Alternatively, the mixture can consist of 30% slate and 70% desert sand. Alternatively, the mixture can consist of 40% slate and 60% desert sand. Alternatively, the mixture can consist of 50% slate and 50% desert sand. Alternatively, the mixture can consist of 60% slate and 40% desert sand. Alternatively, the mixture can consist of 70% slate and 30% desert sand. Alternatively, the mixture can consist of 80% slate and 20% desert sand.

[0033] If the mixture contains other components besides slate and desert sand, it should preferably contain at least 20% slate and at least 20% desert sand.

[0034] The desert sand contained in the mixture can be ground to a grain size of 0.5 mm or smaller.

[0035] Furthermore, it can be considered that the desert sand is ground to a grain size of maximum 0.25 mm, maximum 0.1 mm, maximum 0.75 mm, maximum 0.05 mm or maximum 0.04 mm.

[0036] Bulk materials with a grain size below 0.063 mm are usually referred to as flour rather than sand. The present invention therefore also encompasses embodiments in which slate is ground into slate flour and / or desert sand into corresponding flour.

[0037] The milling process can be designed so that the maximum grain sizes specified above for desert sand also apply to slate. Alternatively, the process can be designed to produce larger slate particles. This can be achieved, for example, by varying the milling time.

[0038] It may be considered to perform at least two grinding steps. Preferably, the grind of the second grinding step is finer than that of the first grinding step.

[0039] The process may also comprise more than two grinding steps, wherein the degree of grinding of each grinding step is preferably finer than the degree of grinding of the previous grinding step.

[0040] In this case, it might be possible to grind slate and desert sand together in the first grinding step. In the second grinding step, one of the two materials, preferably desert sand, can then optionally be added. This is especially true if the slate particles to be ground are initially significantly larger than the desert sand particles, and the proportion of slate in the grinding device is therefore advantageously as high as possible in the first grinding step.

[0041] It may also be considered that no slate or desert sand is added before the second or any subsequent grinding steps, and the ratio of the components of the mixture to be ground is thus determined before the first grinding step.

[0042] Alternatively, you could consider grinding only slate in the first grinding step and adding the desert sand only in the second grinding step.

[0043] In addition to the method described above, the present invention further comprises an additive for a binder or a building material, wherein the additive comprises slate and desert sand that have been ground together. All details and particulars explained with regard to the method described above also apply to the embodiments of the additive, and vice versa.

[0044] The present invention further encompasses a building material or a binder comprising an embodiment of the additive described above. The building material can be selected from a group comprising concrete, mortar, and plaster. The binder can be selected from the group consisting of cement, lime, and pozzolans.

[0045] The present invention further comprises a use of a mixture of jointly ground slate and desert sand as an additive for a binder or a building material.

[0046] The present invention further comprises an additive for a binder or a building material obtained by a process as described above.

Claims

Patent claims 1. A method for producing an additive for a binder or a building material, the method comprising the following steps: - Grinding a mixture containing shale and desert sand.

2. Method according to claim 1, characterized in that the proportion of shale and desert sand in the mixture is at least 20% each.

3. Method according to one of the preceding claims, characterized in that the desert sand is ground to a grain size of 0.5 mm or smaller.

4. Method according to one of the preceding claims, characterized in that at least two grinding steps are carried out, wherein the grinding degree of a second grinding step is finer than that of a first grinding step.

5. Additive for a binder or building material, wherein the additive comprises shale and desert sand which have been ground together.

6. Building material or binder comprising an additive according to claim 5.

7. Use of a mixture of jointly ground shale and desert sand as an additive for a binder or building material.

8. Additive for a binder or a building material obtained by a method according to at least one of claims 1 to 5.