A method for producing amorphous calcined clay clinker for low-carbon lc³

Abstract

This invention relates to a method for preparing low-carbon LC³ amorphous clay clinker by mixing reservoir silt with recycled resources. The method utilizes silt from reservoirs or rivers in different regions as raw materials. The invention is characterized by: separating the silt into clay and silt using a grading technique; analyzing the chemical composition of the clay portion; and adding appropriate amounts of at least one of steelmaking furnace slag, fly ash, volcanic ash, and low-grade kaolin according to the required modulus of LC³ proportions. This corrects for the differences in silt composition from different locations, affecting the LC³ raw material ratio and the required Fe₂O₃ content, resulting in low-carbon clay raw materials for LC³ with different strength requirements. After grinding and refining, the low-carbon clay raw materials for LC³ are calcined using microwave or infrared radiation to dissociate the Al–Si–Fe network, transforming the layered aluminum-silicon-iron minerals into active amorphous phase calcined clay clinker for LC³ at 700-900°C. This invention features the advantages of waste resource recycling, low energy consumption, and low CO₂ emissions, producing active non-crystalline calcined clay clinker. It can process heterogeneous sludge raw materials from different sources and with varying compositions, transforming them into LC³ raw materials with consistent performance. It can be widely used in low-carbon cement, flooring building materials, and environmentally friendly curing materials.

Claims

1. A method for preparing amorphous clay clinker for low-carbon LC³ by mixing reservoir sludge with recycled resources, comprising at least the following steps: (1) Raw material classification and composition analysis: The sludge is classified by ultrasonic cyclone separation to separate clay materials with a particle size <100µm; then the contents of SiO₂, Al₂O₃, and Fe₂O₃ are determined by XRF or FTIR; (2) Automatic batching and proportion correction: Based on the reaction modulus of one of the raw materials for a target low-carbon cement (LC³), an algorithm is used to calculate the amount of one or more recycled resources to be added to the clay; wherein, The recycled resource is a glassy phase material containing silicon, aluminum, and iron, and its glassy phase content is greater than 30 wt%; and according to the addition amount, the recycled resource is mixed into the clay to modify the ratio of silicon dioxide (SiO₂), aluminum oxide (Al₂O₃) and ferric oxide (Fe₂O₃) in the clay, so that the mixed low-carbon clay raw material meets the following conditions: a first ratio SiO₂ / (Al₂O₃+Fe₂O₃) is 1.5 to 4.5; and a second ratio Fe₂O₃ / Al₂O₃ is 0.1 to 1.7; (3) Grinding and calcination activation: The above LC³ low-carbon clay raw material is activated by a grinding aid and then ground to make its specific surface area > 300 m² / kg; and then heated in an environment of 700 to 900 °C by microwave or infrared radiation until the oxygen partial pressure is < 10%. In the environment, microwave or infrared radiation heating is used to dissociate its Al–Si–Fe layered structure and transform it into an active non-crystalline phase of amorphous silica aluminate phase calcined clay clinker, so that its amorphous rate is ≥50%; (4) Quality monitoring and energy consumption reduction: IR / dielectric monitoring and control detection is used to determine the degree of amorphization of the LC³ low carbon clay raw material by means of dielectric constant decrease rate or infrared OH peak ratio.

2. The method for preparing low-carbon LC³ amorphous clay clinker by mixing reservoir silt and recycled resources as described in claim 1, wherein, The calcination activation process is carried out in an environment with an oxygen partial pressure of <10% to avoid recrystallization and increase the proportion of amorphous phase.

3. The method for preparing low-carbon LC³ amorphous clay clinker by mixing reservoir silt and recycled resources as described in claim 1, wherein, The quality control of each step is determined by the dielectric constant decrease rate > 20% or the infrared OH absorption peak disappearance ratio > 0.6 to determine the amorphization endpoint.

4. The method for preparing low-carbon LC³ amorphous clay clinker by mixing reservoir silt and recycled resources as described in claim 1, wherein, The low-carbon LC³ amorphous clay clinker obtained by the aforementioned method contains 10-35 wt% Al₂O₃, 40-70 wt% SiO₂, and 2.5-22 wt% Fe₂O₃.

5. The method for preparing low-carbon LC³ amorphous clay clinker by mixing reservoir silt and recycled resources as described in claim 1, wherein, The low-carbon LC³ calcined clay clinker obtained by the aforementioned method contains ≥60% amorphous phase.

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