阅读说明：本技术 冶金固废钢渣水泥制造方法 (Method for producing metallurgical solid waste steel slag cement ) 是由 席君杰 兰昊 张会峰 刘芸 席天岳 于 2019-08-30 设计创作，主要内容包括：本发明涉及一种冶金固废钢渣制备水泥的方法。冶金固废钢渣浸入一定量水(或其他液体),放入压力容中,加温加压,保温保压一定时间,使水(或其他液体)浸入钢渣中的硅酸二钙、硅酸三钙质密晶体中,瞬间打开压力容器释放压力,使气压迅速下降。由于水浸到钢渣中过烧的硅酸二钙和硅酸三钙的内部,在巨大压差下水分子迅速汽化膨胀,使硅酸二钙、硅酸三钙结晶密度减小,比表面积增大,加快过烧硅酸二钙、硅酸三钙的等物质水化速度,提高钢渣水泥的早期硬度。通过二氧化碳及催化剂加压释放,使游离的氧化钙,氧化镁完全反应成碳酸钙。碳酸镁的稳定成份,避免钢渣水泥后期氧化镁。氧化钙的膨胀不稳定因素。还原出极多的可磁选铁合金粉。(The invention relates to a method for preparing cement by using metallurgical solid waste steel slag. The metallurgical solid waste steel slag is immersed into a certain amount of water (or other liquid), put into a pressure container, heated and pressurized, and kept at the temperature and pressure for a certain time, so that the water (or other liquid) is immersed into the dicalcium silicate and tricalcium silicate dense crystals in the steel slag, and the pressure container is opened instantly to release the pressure, so that the air pressure is reduced rapidly. Because the water is soaked into the interior of the overfire dicalcium silicate and tricalcium silicate in the steel slag, water molecules are quickly vaporized and expanded under a huge pressure difference, the crystallization density of the dicalcium silicate and tricalcium silicate is reduced, the specific surface area is increased, the hydration speed of substances such as the overfire dicalcium silicate and tricalcium silicate is accelerated, and the early hardness of the steel slag cement is improved. The free calcium oxide and magnesium oxide are completely reacted into calcium carbonate through the pressurization and release of carbon dioxide and catalyst. The stable components of the magnesium carbonate avoid later-stage magnesium oxide of the steel slag cement. Swelling instability factor of calcium oxide. Reducing to obtain extremely large magnetically-separable iron alloy powder.)

1. A process for preparing steel slag cement by using pressure difference to destroy the dense crystal of over-sintered dicalcium silicate and tricalcium silicate in steel slag includes such steps as immersing metallurgical solid waste steel slag in water (or liquid of acid, alkali and salt), heating while pressurizing, holding temp for a certain time (or adding catalyst), immersing the liquid in the dense crystal of dicalcium silicate and tricalcium silicate in steel slag, and quickly opening the pressure container. The solid steel slag powder is sprayed together with high-pressure gas, and in the spraying process, as the external pressure intensity is rapidly reduced, a great gas pressure difference is generated, so that liquid molecules in dicalcium silicate and tricalcium silicate in the steel slag are vaporized to destroy dense crystals (like popcorn principle) of dicalcium silicate and tricalcium silicate in the steel slag, the specific surface area is increased, the crystal density is reduced, and the hydration speed is accelerated.

2. The method as claimed in claim 1, wherein in the pressurizing step, carbon dioxide is added to make the free magnesium oxide and calcium oxide heated and pressurized, and the chemical reaction material under the condition of pressure drop generates stable calcium carbonate and magnesium carbonate.

3. The method of claim 1, wherein a trace amount of alkaline water (or acidic water) is added to make the dicalcium silicate and tricalcium silicate compact crystals to be pre-activated by adding sodium silicate and the like for a soaking time (hours to N hours). Or adding catalyst to decompose the dicalcium silicate and tricalcium silicate dense crystals at high temperature and high pressure and under pressure drop, so as to better improve the activity of the overburnt dicalcium silicate and tricalcium silicate in the steel slag and improve the early strength of the steel slag cement.

4. The method of claim 1, wherein the reducing agent is added and the ferroalloy is reduced to yield more magnetically-separable iron. Or negative pressure and vacuum pumping can be adopted, and the internal pressure of the solid waste steel slag is released by positive pressure at the moment when certain negative pressure is reached.

Technical Field

The invention relates to a method for preparing cement by using metallurgical solid waste steel slag.

Background

In the process of steel production, about 10% of solid waste steel slag is produced. The steel smelting temperature is above 1560 ℃. The dicalcium silicate and tricalcium silicate crystals in the steel slag are dense (the sintering temperature of dicalcium silicate C2S and tricalcium silicate C3S in the cement is 1460 ℃ C.) and are difficult to hydrate. The hydration and solidification speed of the steel slag cement is much slower than that of the cement, so that the early strength of the steel slag cement is very low, and the application of the steel slag cement is influenced. And the steel slag contains certain free magnesium oxide and calcium oxide, and absorbs carbon dioxide in air at the later stage of solidification of the steel slag cement, so that the volume expansion causes the strength reduction of the concrete.

Disclosure of Invention

The invention aims to provide a preparation method of steel slag cement, which enables metallurgical solid waste steel slag to reach the cement standard.

The preparation method of the steel slag cement comprises the following steps:

a pressure vessel is provided.

The steel slag is soaked in water (or other liquid) and put into a pressure container, and carbon dioxide (or other catalysts and the like) is added into the pressure container, so that free magnesium oxide and calcium oxide are completely reacted into calcium carbonate and magnesium carbonate.

Heating and pressurizing.

Keeping the temperature and the pressure for a certain time to promote the liquid to be immersed into the crystals with dense quality of the over-burnt dicalcium silicate and tricalcium silicate.

The pressure container is opened rapidly, the pressure of the steel slag is released instantaneously along with the pressure drop of air, the pressure of dicalcium silicate C2S and tricalcium silicate C3S in the steel slag is released instantaneously, and water molecules in dense crystals of the steel slag are vaporized and expanded rapidly (the effect of popcorn is generated). The internal stress is released to form a larger specific surface area, so that the activity of dicalcium silicate and tricalcium silicate is greatly enhanced, and the early strength of the steel slag cement is improved. The steel slag is soaked in water (or other liquid) and put into a pressure container to be filled with carbon dioxide to form carbonic acid, and the same effect can be achieved by heating and pressurizing the carbonic acid and releasing the carbonic acid.

The metallurgical solid waste can be used for manufacturing cement by a pressure container and a pressure release method.

Detailed Description

The process for preparing cement from metallurgical solid waste steel slag (powder) according to the present invention will be described by way of example.

Soaking the steel slag in 20% of water, standing for 24 hours, putting the steel slag into a pressure container, introducing carbon dioxide (heating and pressurizing) to 0.8 MPa, keeping the temperature at 100 ℃, and maintaining the pressure for 30 minutes to release the pressure. So that the steel slag fine powder is quickly dropped and sprayed into a steel slag powder bin along with the pressure (like a popcorn machine). After the water is vaporized, it evaporates with the temperature.

Pressurizing the smelted steel slag in a hot closed container, adding carbon dioxide, maintaining the pressure for 3 hours at 0-3 MPa, and releasing the pressure at 100 ℃ to vaporize water to destroy the dense crystals of dicalcium silicate and tricalcium silicate in the overburnt steel slag.

The steel slag is added with 30 percent of water and carbon dioxide, heated to 120 ℃, pressurized to 0.5 MPa, kept for 30 minutes and released with pressure instantly.

Mixing hot steel slag with 10% of silicon dioxide powder and 10% of coke powder, adding the mixture into a pressure container, and introducing carbon dioxide under the pressure of 0.5 MPa and the temperature of 1000 ℃. The temperature is reduced to 200 ℃, the pressure is quickly released, and the silicon dioxide reacts with the hot steel slag to generate dicalcium silicate with extremely high activity. Tricalcium silicate meets the strength requirements of early stage hydraulic cement.

Soaking the steel slag fine powder in water, mixing the steel slag fine powder with 3% by volume of weak alkaline lime, adding the mixture into a pressure container, heating to 300 ℃, pressurizing to 0.5 MPa, and preserving heat and pressure for 20 minutes. The pressure is released instantly to destroy the structure of the over-burnt dicalcium silicate and tricalcium silicate. The specific surface area and the activity are increased, and the early hydraulic cement strength is achieved.

Mixing the steel slag powder with 5% of alkalescent phosphoric acid, heating to 200 ℃, pressurizing to 0.5 MPa, preserving heat and pressure for 20 minutes, and releasing pressure instantly.