DE-102024133260-A1 - Grinding process for the dry grinding of a lumpy material and process for the production of cement

DE102024133260A1DE 102024133260 A1DE102024133260 A1DE 102024133260A1DE-102024133260-A1

Abstract

Inventors

Fulvio Canonico
Alberta Pellegrino
Stefan Schubert

Assignees

BUZZI S.P.A.
DYCKERHOFF GMBH

Dates

Publication Date: 20260513
Application Date: 20241113

Claims (20)

Grinding process for dry grinding of a lumpy material using a grinding aid, wherein the material being ground comprises particles made of at least one inorganic material, preferably at least one cement clinker, and wherein the grinding aid is added to the material being ground before or during grinding, characterized in that at least one grinding aid containing biochar is added.
Grinding process according to Claim 1 , characterized in that the total amount of biochar added is 0.05 to 0.25 wt.%, preferably 0.05 to 0.10 wt.%, based on the total mass of the ground material particles made of inorganic material.
Grinding process according to Claim 1 or 2 , characterized in that the regrind comprises regrind particles of cement clinker, preferably Portland cement clinker and/or aluminate cement clinker and/or calcium sulfoaluminate cement clinker, and/or of setting regulators, preferably gypsum and/or anhydrite and/or hemihydrate, and/or of granulated blast furnace slag and/or of limestone and/or of a natural or naturally tempered pozzolan, preferably calcined clay and/or microsilica, and/or of fly ash.
Milling method according to one of the preceding claims, characterized in that the material to be milled is ground to a flour with a particle size ≤ 200 µm, preferably < 150 µm, determined by laser diffraction according to ISO 13320:2020-01 and/or with a Blaine value of ≥ 3500 cm² /g, determined according to DIN EN 196-6:2019-03.
Grinding method according to one of the preceding claims, characterized in that the biochar comprises at least one type of biochar produced from wood charcoal, wherein the biochar preferably consists of at least one type of biochar produced from wood charcoal.
Grinding process according to one of the preceding claims, characterized in that the biochar comprises at least one type of biochar produced from sewage sludge.
Grinding process according to one of the preceding claims, characterized in that the at least one grinding aid is in dry or liquid form and is added.
Grinding process according to Claim 7 , characterized in that the dry grinding aid consists of at least 80 wt.%, preferably at least 97 wt.%, particularly preferably 100 wt.%, biochar particles.
Grinding process according to Claim 7 or 8 , characterized in that the liquid grinding aid is a suspension comprising a liquid phase in which the biochar particles are dispersed, wherein the liquid phase preferably consists of water and/or an organic liquid, wherein the organic liquid is preferably a liquid which also improves the grindability, preferably triethanolamine (TEOA) and/or triisopropanolamine (TIPA).
Grinding process according to Claim 9 , characterized in that the suspension has a content of 3 to 70 wt.%, preferably 10 to 60 wt.%, preferably 30 to 50 wt.%, biochar, based on the total mass of the grinding aid.
Grinding process according to one of the preceding claims, characterized in that the at least one grinding aid comprises further components in liquid and/or solid form, preferably at least one flow agent, preferably based on lignosulfonate, naphthalenesulfonate or polycarboxylate ether, and/or at least one retarder, preferably sodium gluconate or potassium gluconate or phosphoric acid, and/or at least one accelerator and/or at least one chromate reducer, preferably based on iron(II) sulfate or tin(II) sulfate.
Grinding process according to one of the preceding claims, characterized in that the biochar of the at least one grinding aid has a BET surface area of 100 to 450 m² /g, preferably 120 to 300 m² /g, particularly preferably 120 to 240 m² /g, and/or a BET surface area < 450 m² /g, preferably ≤ 300 m² /g, particularly preferably ≤ 240 m² /g, each determined according to DIN ISO 9277:2014-01.
Grinding process according to one of the preceding claims, characterized in that the biochar (anhydrous) of the at least one grinding aid has a carbon content of ≥ 60 wt.%, preferably ≥ 70 wt.%, preferably ≥ 85 wt.%, determined according to DIN 51732:2014-07.
Grinding process according to one of the preceding claims, characterized in that the biochar contains mineral ash, wherein the biochar (anhydrous) preferably has a mineral ash content of 1.5 to 30 wt.%, preferably 2 to 15 wt.%, determined according to DIN 51719:1997-07 at 550 °C.
Grinding process according to one of the Claims 7 until 12 , characterized in that the biochar of the at least one dry grinding aid has a maximum particle size ≤ 1000 µm, preferably ≤ 500 µm, determined by laser diffraction according to ISO 13320:2020-01, and/or the biochar of the at least one liquid grinding aid has a maximum particle size ≤ 100 µm, determined by laser diffraction according to ISO 13320:2020-01.
Grinding method according to one of the preceding claims, characterized in that the grinding takes place in a mill, preferably in a mill having grinding bodies, preferably a ball mill, or in a mill having rotating rollers, preferably a roller bowl mill or a good bed roller mill, or in a combination grinding operation of roller and ball mill.
Grinding method according to one of the preceding claims, characterized in that the grinding time in a mill having grinding media, preferably in a ball mill, is 15 to 45 minutes, preferably 20 to 30 minutes.
A method for producing a dry, hydraulically setting cement, comprising at least one cement clinker, preferably Portland cement clinker and/or alumina cement clinker and/or calcium sulfoaluminate cement clinker, optionally at least one setting regulator, and optionally further inorganic cement components, wherein the individual inorganic cement components are mixed together for the production of the cement and are ground at least partially before and/or after mixing, wherein the cement components are ground separately from one another or at least partially together, characterized in that the cement components are ground at least partially according to the grinding method according to one of the preceding claims.
Procedure according to Claim 18 , characterized in that at least one cement clinker is produced according to the grinding process according to one of the Claims 1 until 17 is ground.
Procedure according to Claim 18 or 19 , characterized in that a cement is produced which has 95-100 wt.% main components and 0-5 wt.% minor components, in each case based on the sum of main and minor components, and in addition to the main and minor components has at least one setting regulator.

Description

The present invention relates to a grinding process for the dry grinding of a free-flowing or lumpy material comprising particles of at least one inorganic material, preferably cement clinker, preferably Portland cement clinker and/or aluminate cement clinker and/or calcium sulfoaluminate cement clinker, and/or other inorganic cement constituents. The invention further relates to a process for producing cement from the meal produced by grinding. "Pourable" means that the material being ground is in bulk form. Bulk material is, as is well known, a mixture consisting of individual particles or grains (=lumpy material) that is in a pourable form. Cement is a well-known hydraulic, inorganic binder that solidifies and hardens through a chemical reaction with water (hydration) and remains stable even underwater after hardening. Cement is finely ground or powdery. It consists of a mixture of finely ground, non-metallic, inorganic components. It is also a bulk material. In the context of the invention, "flour-like" means a particle size ≤ 150 µm. Unless otherwise specified, the determination of grain sizes within the scope of the invention is also carried out by means of laser light diffraction according to ISO 13320:2020-01 . Cements can be distinguished, among other things, by the cement clinker they contain: Cements containing Portland cement clinker are classified according to their composition as follows: DIN EN 197-1:2011-11 and the DIN EN 197-5:2021-07 Cements are classified into different types, or standard cements, or standard cements CEM I-VI. All cement types contain at least 95% by mass of main constituents and at most 5% by mass of minor constituents, based on the sum of main and minor constituents. The main constituents, besides Portland cement clinker (K), are granulated blast furnace slag (S), silica fume (D), natural pozzolans (P), natural tempered pozzolans (Q), silica-rich fly ash (V), lime-rich fly ash (W), burnt shale (T), and limestone (L or LL). Each main constituent must be present at a minimum of 5% by mass, based on the sum of main and minor constituents. Portland cement clinker is known to consist essentially of four clinker phases: tricalcium silicate (alite) C₃S , dicalcium silicate (belite) C₂S , tricalcium aluminate C₃A , and tetracalcium aluminate ferrite C₄AF . Portland cement clinker may also contain free CaO (calcium oxide). The clinker phases are known to react primarily with hydration to form calcium silicate hydrate phases (CSH phases). Furthermore, the hydration of C₃S and C₂S is known to form portlandite (calcium hydroxide (Ca(OH) ₂ )). The secondary constituents are specially selected inorganic natural mineral substances, inorganic mineral substances derived from clinker production, or constituents as described in section 5.2 of DIN EN 197-1:2011-11, unless they are already present as main constituents in the cement. Cement containing Portland cement clinker also contains calcium sulfate, in addition to its main and minor constituents, to regulate its setting behavior. Calcium sulfate may be present in the form of gypsum, hemihydrate, anhydrite, or a mixture thereof. The proportion of calcium sulfate carrier is calculated as a percentage of the total main and minor constituents. Alumina cement (also known as alumina fused cement, calcium aluminate cement, or CAC cement) is used, for example, in the DIN EN 14647: 2006-01 Standardized. Alumina cement contains alumina cement clinker. This differs fundamentally in its phase composition from the Portland cement clinker of silicate-rich standard cements. A key component of alumina cement clinker is monocalcium aluminate (CA). Additionally, alumina cement clinker with a higher lime content may contain C12A7 , and clinker with a lower lime content may contain CA2 . The clinker phases are known to react primarily to form calcium aluminate hydrate phases (CAH phases) during hydration. Calcium aluminate clinker cements may also contain other inorganic cement components. Calcium sulfoaluminate cement (CSA cement) is a type of cement developed in China. It typically consists of calcium sulfoaluminate clinker and an accelerant, such as gypsum or anhydrite. However, it can also consist solely of ground calcium sulfoaluminate clinker. The main component of calcium sulfoaluminate clinker is the anhydrous sulfate Ye'elimit, with the composition C₃A₃Cs ( Ca₄Al₆O₁₂ ( SO₄ ) ₂ ). Other components include C₂S (belite), gehlenite, brownmillerite, ternesite, spinel , and other minor phases. If iron-rich raw materials are used in its production, a ferritic calcium sulfoaluminate clinker is formed. During the hydration of calcium sulfoaluminate cement, ettringite, monosulfate, aluminum hydroxide, CSH phases, strätlingite, and calcium hydroxide can be formed. Cements containing calcium sulfoaluminate clinker may also contain other inorganic cement components. Also known are cements that contain several different cement clinkers to control specific prop