The present invention refers to a manufacturing process of artificial pozzolan which has the final color gray. In order to perform the processes in the desired way, the kiln atmosphere shall contain low oxygen concentration and the presence of reducing agents. However the presence of carbon monoxide at the kiln outlet is not desirable, due to environmental impacts and the increase in specific heat consumption of the kiln. So the process described in this invention comprises the following steps: heating (1), which consists of heating the raw materials to a temperature between 100-350° C. until drying of the material to a moisture mass fraction of 0-5% (wet basis); mixing (2), which consists of mixing the dry raw materials from the heating process with the right proportion of fuel, in from 1% to 5% in mass fraction, according to the concentration of hematite present in the raw material; calcining (3), which consists of heating the fuel and raw materials blend to a temperature between 700-900° C., with oxygen concentration between 1-5% and, finally, cooling (4), which consists of an initial step of rapid decrease in pozzolan temperature until 600° C. and a final step of slow decrease in pozzolan temperature until 120° C.

An apparatus for recycling fly ash has a quantum energy generator therein. The apparatus recycles fly ash generated as the combustion waste from the burning of coal in thermal power plants, into construction materials such as cement substitutes, environment-friendly cover materials, etc. Unburned pulverized coal is removed while generating carbon monoxide (CO) or carbon dioxide (CO.sub.2) through a combustion reaction, in which the unburned pulverized coal of the fly ash contacts the thermal electrons discharged during a thermal decomposition process at a high temperature, the negative electrodes of the thermal decomposition part, which are heated at a high temperature of 500° C., which is an ignition point of the unburned pulverized coal, or higher, and a high-voltage discharge electrode of an electrochemical reaction part, then heated at 500° C. or higher, and then naturally burned under an oxygen atmosphere (oxygen or ionized oxygen ions in air contained in the fly ash).

A process for producing cement clinker may involve preheating raw meal in a preheater, calcining the preheated raw meal in a calciner, burning the preheated and calcined raw meal in a furnace to give cement clinker, cooling the cement clinker in a cooler, branching off a portion of the furnace offgases flowing out of the furnace as bypass gas, cooling the bypass gas in a mixing chamber with a cooling gas, and separating out dust present in the bypass gas. The cooling gas is formed at least partly or completely from the bypass gas and/or the calciner offgas and/or the preheater offgas. The cooling gas is introduced into the mixing chamber in a ratio of 2-10:1 relative to the bypass gas.

Processes and plants for producing cement clinker, in which an oxygen-containing gas having a proportion of 15% by volume or less of nitrogen and a proportion of 50% by volume or more of oxygen is conveyed from a first section of the cooler directly adjoining the top of the furnace into the rotary furnace and is optionally additionally conveyed to the calciner, and where the total gas streams fed in to the combustion processes consist to an extent of more than 50% by volume (preferably more than 85% by volume) of oxygen.

In a method for reducing the NOx emissions of a rotary kiln of a clinker production plant, fuel supplied through a burner of the rotary kiln is burned along with primary air fed through the burner, wherein the primary air has a lower oxygen content and the primary air has an oxygen content reduced relative to that of the ambient air and a temperature increased relative to that of the ambient air, and the primary air is obtained by mixing ambient air with exhaust gas from the rotary kiln or from a heat exchanger connected to the rotary kiln and used for preheating raw meal. The primary air is further obtained by mixing with hot air, in particular waste air from a clinker cooler.

In a method for reducing the NOx emissions of a rotary kiln of a clinker production plant, fuel supplied through a burner of the rotary kiln is burned along with primary air fed through the burner, wherein the primary air has a lower oxygen content and the primary air has an oxygen content reduced relative to that of the ambient air and a temperature increased relative to that of the ambient air, and the primary air is obtained by mixing ambient air with exhaust gas from the rotary kiln or from a heat exchanger connected to the rotary kiln and used for preheating raw meal. The primary air is further obtained by mixing with hot air, in particular waste air from a clinker cooler.

An apparatus for recycling fly ash has a quantum energy generator therein. The apparatus recycles fly ash generated as the combustion waste from the burning of coal in thermal power plants, into construction materials such as cement substitutes, environment-friendly cover materials, etc. Unburned pulverized coal is removed while generating carbon monoxide (CO) or carbon dioxide (CO.sub.2) through a combustion reaction, in which the unburned pulverized coal of the fly ash contacts the thermal electrons discharged during a thermal decomposition process at a high temperature, the negative electrodes of the thermal decomposition part, which are heated at a high temperature of 500 C., which is an ignition point of the unburned pulverized coal, or higher, and a high-voltage discharge electrode of an electrochemical reaction part, then heated at 500 C. or higher, and then naturally burned under an oxygen atmosphere (oxygen or ionized oxygen ions in air contained in the fly ash).

The present invention refers to a manufacturing process of artificial pozzolan which has the final color gray. In order to perform the processes in the desired way, the kiln atmosphere shall contain low oxygen concentration and the presence of reducing agents. However the presence of carbon monoxide at the kiln outlet is not desirable, due to environmental impacts and the increase in specific heat consumption of the kiln. So the process described in this invention comprises the following steps: heating (1), which consists of heating the raw materials to a temperature between 100-350 C. until drying of the material to a moisture mass fraction of 0-5% (wet basis); mixing (2), which consists of mixing the dry raw materials from the heating process with the right proportion of fuel, in from 1% to 5% in mass fraction, according to the concentration of hematite present in the raw material; calcining (3), which consists of heating the fuel and raw materials blend to a temperature between 700-900 C., with oxygen concentration between 1-5% and, finally, cooling (4), which consists of an initial step of rapid decrease in pozzolan temperature until 600 C. and a final step of slow decrease in pozzolan temperature until 120 C.

Processes and plants for producing cement clinker, in which an oxygen-containing gas having a proportion of 15% by volume or less of nitrogen and a proportion of 50% by volume or more of oxygen is conveyed from a first section of the cooler directly adjoining the top of the furnace into the rotary furnace and is optionally additionally conveyed to the calciner, and where the total gas streams fed in to the combustion processes consist to an extent of more than 50% by volume (preferably more than 85% by volume) of oxygen.

The present disclosure provides an energy-efficient (low energy consumption), carbon enriched cement production system and a method for producing cement clinker. This system involves raw material preheating and precalcining system and sequentially connected kiln inlet chamber, rotary kiln and cooler, wherein the raw material preheating and precalcining system involves precalciner and preheater, and the cooler involves first cooling zone and second cooling zone. The first cooling zone includes first cooling partition and second cooling partition, wherein a mixture of pure oxygen and high-concentration CO.sub.2 flue gas entering the inlet of the first cooling partition, high-concentration CO.sub.2 flue gas entering the inlet of the second cooling partition, and air entering the inlet of the second cooling zone have solved the problems in existing cement kiln CO.sub.2 enrichment technology, i.e., extensive air leakage and high energy consumption between the first cooling zone and the second cooling zone.