A method for preparing silicate cement clinker using coal-based hydrogen metallurgical dry separation tailings as an iron source

Abstract

This invention provides a method for preparing silicate cement clinker using coal-based hydrogen metallurgical dry separation tailings as the iron source. The raw materials are weighed and mixed according to the following weight percentages: limestone 66-74%, silica fume 0-3%, clay 13-18%, Fe2O3 powder 2%, and coal-based hydrogen metallurgical dry separation tailings 6-23%. The mixture is then ground into raw meal using a vertical mill to a fineness of 0.08 mm. The raw meal is dried and pre-decomposed in an external decomposition furnace, achieving a decomposition rate of over 95%. After calcination in a rotary kiln, it is cooled to form silicate cement clinker. This method saves iron and calcium mineral resources, lowers the cement calcination temperature, and not only reduces the production cost of silicate clinker, saving energy and reducing carbon emissions, but also enables large-scale comprehensive utilization of coal-based hydrogen metallurgical dry separation tailings, promoting ecological environmental protection.

Description

Technical Field

[0001] This invention belongs to the field of building materials technology and relates to a method for preparing silicate cement clinker using coal-based hydrogen metallurgical dry separation tailings as an iron source. Background Technology

[0002] Coal-based hydrogen metallurgical dry separation tailings are powdery solid waste obtained through dry grinding and separation in the coal-based hydrogen metallurgical technology process. With the widespread application of coal-based hydrogen metallurgical technology, a large amount of coal-based hydrogen metallurgical dry separation tailings will inevitably be generated. If left to accumulate, this not only occupies land resources and increases the burden on enterprises, but also generates various forms of pollution, including dust, soil, and water pollution, placing enormous pressure on the natural environment. How to dispose of coal-based hydrogen metallurgical dry separation tailings on a large scale is an urgent problem that the steel solid waste industry needs to solve. Coal-based hydrogen metallurgical dry separation tailings are rich in carbon and iron, making them one of the high-quality materials for replacing iron-based raw materials in silicate cement clinker. Developing silicate cement clinker preparation technology using coal-based hydrogen metallurgical dry separation tailings as an iron source is of great significance for realizing the large-scale comprehensive utilization of coal-based hydrogen metallurgical dry separation tailings and conserving iron and calcium mineral resources. Summary of the Invention

[0003] The purpose of this invention is to provide a method for preparing silicate cement clinker using coal-based hydrogen metallurgical dry separation tailings as an iron source.

[0004] The present invention adopts the following technical solution, specifically including the following steps:

[0005] (1) According to the principle of medium lime saturation coefficient, high silicon and medium aluminum, the clinker ratio is determined as follows: lime saturation coefficient KH=0.89±0.02, silicon ratio SM=2.1±0.1, aluminum ratio IM=1.3±0.1; according to the weight percentage: limestone 66-74%, silica fume 0-3%, clay 13-18%, Fe2O3 powder 2%, coal-based hydrogen metallurgical dry separation tailings 6-23%, the materials are weighed and mixed, and then ground in a vertical mill; the preferred weight percentage is: limestone 74%, clay 18%, Fe2O3 powder 2%, coal-based hydrogen metallurgical dry separation tailings 6%.

[0006] (2) Raw material is ground into a thickness of 0.07-0.09 mm (preferably 0.08 mm) by a vertical mill;

[0007] (3) The raw materials are dried and pre-decomposed in an external decomposition furnace, with a decomposition rate of over 95%. After being calcined in a rotary kiln at 1350-1450℃, they are cooled by a cooler to form silicate cement clinker.

[0008] The chemical composition of the limestone, by weight percentage, is: SiO2 2.4-2.6%, Al2O3 0.3-0.5%, Fe2O3 0.1-0.2%, CaO 52-53%, MgO 0.5-0.6%, with the balance being other substances, and a loss on ignition of 40-42%. Preferably, the chemical composition of the limestone, by weight percentage, is: SiO2 2.4%, Al2O3 0.3%, Fe2O3 0.2%, CaO 53%, MgO 0.6%, with a loss on ignition of 42.2%.

[0009] The chemical composition of silica fume, by weight percentage, is: SiO2 92-96%, Al2O3 0.8-1.2%, Fe2O3 0.6-1.2%, CaO 0.2-0.4%, MgO 0.6-0.8%, with the balance being other substances, and a loss on ignition of 2.0-2.5%. Preferably, the chemical composition of silica fume, by weight percentage, is: SiO2 96%, Al2O3 0.8%, Fe2O3 1.0%, CaO 0.3%, MgO 0.7%, with a loss on ignition of 2.5%.

[0010] The chemical composition of the clay, by weight percentage, is: SiO2 70-74%, Al2O3 13-15%, Fe2O3 5.4-5.6%, CaO 1.3-1.5%, MgO 0.9-1.1%, with the balance being other substances, and a loss on ignition of 5-6%. Preferably, the chemical composition of the clay, by weight percentage, is: SiO2 70%, Al2O3 14%, Fe2O3 5.5%, CaO 1.4%, MgO 0.9%, with a loss on ignition of 5.2%.

[0011] The chemical composition of coal-based hydrogen metallurgical dry separation tailings, by weight percentage, is: SiO2 22-25%, Al2O3 9-10%, Fe2O3 12-14%, CaO 14-15%, MgO 3-4%, with the balance being other substances, and a loss on ignition of 15-22%. Preferably, the chemical composition of coal-based hydrogen metallurgical dry separation tailings, by weight percentage, is: SiO2 22%, Al2O3 9%, Fe2O3 12%, CaO 14%, MgO 3%, with a loss on ignition of 20.5%.

[0012] The beneficial effects of this invention are:

[0013] This invention uses coal-based hydrogen metallurgical dry separation tailings solid waste as raw material to prepare silicate cement clinker, which can save grinding energy consumption. It partially replaces iron-based correction raw materials and partially replaces calcium-based raw materials with coal-based hydrogen metallurgical dry separation tailings, thus conserving natural iron and calcium resources. The coal-based hydrogen metallurgical dry separation tailings used contain a certain amount of residual carbon, which can be used as an internal heat source to provide heat, reducing calcination energy consumption. As waste residue generated from the new coal-based hydrogen metallurgical process, the dry separation tailings are used to prepare silicate cement clinker, meeting the requirements of GB / T 175-2007 "General Silicate Cement". This helps reduce the production cost of silicate clinker, saves energy and reduces carbon emissions, and also enables large-scale comprehensive utilization of coal-based hydrogen metallurgical dry separation tailings, promoting ecological environmental protection. Detailed Implementation

[0014] Example 1

[0015] (1) Batching: According to the batching principle of medium lime saturation coefficient, high silicon and medium aluminum, the clinker rate value is determined as follows: KH=0.89±0.02, SM=2.1±0.1, IM=1.3±0.1. According to the weight percentage: limestone 74%, clay 18%, Fe2O3 powder 2%, coal-based hydrogen metallurgical dry separation tailings 6%, the materials are weighed and mixed, and then fed into the vertical mill for grinding.

[0016] The chemical composition of the limestone used, by weight percentage, is: SiO2 2.4%, Al2O3 0.3%, Fe2O3 0.2%, CaO 53%, MgO 0.6%, with a loss on ignition of 42.2%. The chemical composition of the silica fume used, by weight percentage, is: SiO2 96%, Al2O3 0.8%, Fe2O3 1.0%, CaO 0.3%, MgO 0.7%, with a loss on ignition of 2.5%. The chemical composition of the clay used, by weight percentage, is: SiO2 70%, Al2O3 14%, Fe2O3 5.5%, CaO 1.4%, MgO 0.9%, with a loss on ignition of 5.2%. The chemical composition of the coal-based hydrogen metallurgical dry beneficiation tailings used, by weight percentage, is: SiO2 22%, Al2O3 9%, Fe2O3 12%, CaO 14%, MgO 3%, with a loss on ignition of 20.5%.

[0017] (2) The raw material is ground into powder by vertical mill and the raw material is ground to 0.08 mm.

[0018] (3) The raw materials are dried and pre-decomposed in the external decomposition furnace, with a decomposition rate of over 95%. After being calcined in the rotary kiln at 1450°C, they are cooled by the cooler to form silicate cement clinker.

[0019] Example 2

[0020] (1) Batching: According to the batching principle of medium lime saturation coefficient, high silica and medium aluminum, the clinker rate value is determined as follows: KH=0.89±0.02, SM=2.1±0.1, IM=1.3±0.1. The following materials are weighed and mixed according to the following weight percentages: limestone 72%, silica fume 3%, clay 13%, Fe2O3 powder 2%, coal-based hydrogen metallurgical dry separation tailings 8%, and then fed into the vertical mill for grinding.

[0021] The chemical composition of the limestone used, by weight percentage, is: SiO2 2.4%, Al2O3 0.3%, Fe2O3 0.2%, CaO 53%, MgO 0.6%, with a loss on ignition of 42.2%. The chemical composition of the silica fume used, by weight percentage, is: SiO2 96%, Al2O3 0.8%, Fe2O3 1.0%, CaO 0.3%, MgO 0.7%, with a loss on ignition of 2.5%. The chemical composition of the clay used, by weight percentage, is: SiO2 70%, Al2O3 14%, Fe2O3 5.5%, CaO 1.4%, MgO 0.9%, with a loss on ignition of 5.2%. The chemical composition of the coal-based hydrogen metallurgical dry beneficiation tailings used, by weight percentage, is: SiO2 22%, Al2O3 9%, Fe2O3 12%, CaO 14%, MgO 3%, with a loss on ignition of 20.5%.

[0022] (2) The raw material is ground into powder by vertical mill and the raw material is ground to 0.08 mm.

[0023] (3) The raw materials are dried and pre-decomposed in the external decomposition furnace, with a decomposition rate of over 95%. After being calcined in the rotary kiln at 1450°C, they are cooled by the cooler to form silicate cement clinker.

[0024] Example 3

[0025] (1) Batching: According to the batching principle of medium lime saturation coefficient, high silica and medium aluminum, the clinker rate value is determined as follows: KH=0.89±0.02, SM=2.1±0.1, IM=1.3±0.1. According to the weight percentage: limestone 70%, silica fume 3%, clay 13%, Fe2O3 powder 2%, coal-based hydrogen metallurgical dry separation tailings 12%, the materials are weighed and mixed, and then fed into the vertical mill for grinding.

[0026] The chemical composition of the limestone used, by weight percentage, is: SiO2 2.4%, Al2O3 0.3%, Fe2O3 0.2%, CaO 53%, MgO 0.6%, with a loss on ignition of 42.2%. The chemical composition of the silica fume used, by weight percentage, is: SiO2 96%, Al2O3 0.8%, Fe2O3 1.0%, CaO 0.3%, MgO 0.7%, with a loss on ignition of 2.5%. The chemical composition of the clay used, by weight percentage, is: SiO2 70%, Al2O3 14%, Fe2O3 5.5%, CaO 1.4%, MgO 0.9%, with a loss on ignition of 5.2%. The chemical composition of the coal-based hydrogen metallurgical dry beneficiation tailings used, by weight percentage, is: SiO2 22%, Al2O3 9%, Fe2O3 12%, CaO 14%, MgO 3%, with a loss on ignition of 20.5%.

[0027] (2) The raw material is ground into powder by vertical mill and the raw material is ground to 0.08 mm.

[0028] (3) The raw materials are dried and pre-decomposed in the external decomposition furnace, with a decomposition rate of over 95%. After being calcined in the rotary kiln at 1450°C, they are cooled by the cooler to form silicate cement clinker.

[0029] Example 4

[0030] (1) Batching: According to the batching principle of medium lime saturation coefficient, high silicon and medium aluminum, the clinker rate value is determined as follows: KH=0.89±0.02, SM=2.1±0.1, IM=1.3±0.1. According to the weight percentage: limestone 66%, silica fume 3%, clay 13%, Fe2O3 powder 2%, coal-based hydrogen metallurgical dry separation tailings 16%, the materials are weighed and mixed, and then fed into the vertical mill for grinding.

[0031] The chemical composition of the limestone used, by weight percentage, is: SiO2 2.4%, Al2O3 0.3%, Fe2O3 0.2%, CaO 53%, MgO 0.6%, with a loss on ignition of 42.2%. The chemical composition of the silica fume used, by weight percentage, is: SiO2 96%, Al2O3 0.8%, Fe2O3 1.0%, CaO 0.3%, MgO 0.7%, with a loss on ignition of 2.5%. The chemical composition of the clay used, by weight percentage, is: SiO2 70%, Al2O3 14%, Fe2O3 5.5%, CaO 1.4%, MgO 0.9%, with a loss on ignition of 5.2%. The chemical composition of the coal-based hydrogen metallurgical dry beneficiation tailings used, by weight percentage, is: SiO2 22%, Al2O3 9%, Fe2O3 12%, CaO 14%, MgO 3%, with a loss on ignition of 20.5%.

[0032] (2) The raw material is ground into powder by vertical mill and the raw material is ground to 0.08 mm.

[0033] (3) The raw materials are dried and pre-decomposed in the external decomposition furnace, with a decomposition rate of over 95%. After being calcined in the rotary kiln at 1450°C, they are cooled by the cooler to form silicate cement clinker.

[0034] The performance parameters of the silicate cement clinker prepared by the above process are shown in the table below:

[0035]

[0036] All examples showed an f-CaO content below 1.5%, meeting the requirements of the national standard GB / T 21372-2008 "Silicate Cement Clinker". All examples exhibited compressive strength above 42.5 MPa, initial setting time ≥45 min, and final setting time ≤390 min, meeting the requirements of the national standard GB / T 175-2007 "General Silicate Cement". Dry-separated tailings, as waste residue from the new coal-based hydrogen metallurgical process, can be used to prepare silicate cement clinker. This helps reduce the production cost of silicate clinker, saves energy and reduces carbon emissions, and enables large-scale comprehensive utilization of dry-separated tailings from coal-based hydrogen metallurgical processes, promoting ecological environmental protection.

Claims

1. A method for preparing silicate cement clinker using coal-based hydrogen metallurgical dry separation tailings as an iron-based raw material, comprising the following steps: (1) According to the batching principle of medium lime saturation coefficient, high silicon and medium aluminum, the clinker ratio is determined as follows: lime saturation coefficient KH=0.89±0.02, silicon ratio SM=2.1±0.1, aluminum ratio IM=1.3±0.1; Weigh and mix the following raw materials by weight percentage: limestone 66-74%, silica fume 0-3%, clay 13-18%, Fe2O3 powder 2%, and coal-based hydrogen metallurgical dry separation tailings 6-23%, and then grind them in a vertical mill. The total weight percentage of the above raw materials shall be 100%. (2) Raw material is ground to a thickness of 0.07-0.09 mm using a vertical mill; (3) The raw materials are dried and pre-decomposed in the external decomposition furnace, and the decomposition rate reaches more than 95%. After being sent to the rotary kiln for calcination at 1350-1450℃, they are cooled by the cooler to form silicate cement clinker. The chemical composition of limestone by weight percentage is: SiO2 2.4-2.6%, Al2O3 0.3-0.5%, Fe2O3 0.1-0.2%, CaO 52-53%, MgO 0.5-0.6%, with the balance being other substances, and a loss on ignition of 40-42%. The chemical composition of silica fume by weight percentage is: SiO2 92-96%, Al2O3 0.8-1.2%, Fe2O3 0.6-1.2%, CaO 0.2-0.4%, MgO 0.6-0.8%, with the balance being other substances, and a loss on ignition of 2.0-2.5%. The chemical composition of the clay, by weight percentage, is as follows: SiO2 70-74%, Al2O3 13-15%, Fe2O3 5.4-5.6%, CaO 1.3-1.5%, MgO 0.9-1.1%, with the balance being other substances; loss on ignition 5-6%. The chemical composition of coal-based hydrogen metallurgical dry separation tailings powder by weight percentage is as follows: SiO2 22-25%, Al2O3 9-10%, Fe2O3 12-14%, CaO 14-15%, MgO 3-4%, with the balance being other substances, and loss on ignition 15-22%.

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