CN1253396C

CN1253396C - Method for preparing cement clinker by using chrome slag as mineralization agent

Info

Publication number: CN1253396C
Application number: CNB021336342A
Authority: CN
Inventors: 李光荣; 蒋清平; 青兴全; 王亭刚; 赵云凯; 张松柏; 叶明光
Original assignee: YINHE JIANHUA GROUP CO Ltd AN COUNTY SICHUAN
Current assignee: Sichuan Yinhe Chemical Co ltd
Priority date: 2002-08-19
Filing date: 2002-08-19
Publication date: 2006-04-26
Anticipated expiration: 2022-08-19
Also published as: CN1477073A

Abstract

The present invention discloses a method for preparing cement clinker by using chromium slag as a mineralizing agent. A cement raw material is mainly added in chromium slag which is a mineralizing agent, hexavalent chrome is reduced into trivalent chromium by calcination at high temperature, and meanwhile, cement clinker is made by adding a catalysis stabilizing agent in clinker. The cement clinker prepared by the method of the present invention has the advantages of low production cost, stable technology and low content of the hexavalent chrome in a product, and product quality can completely reach a national standard.

Description

Method for preparing cement clinker by using chromium slag as mineralizer

Technical Field

The invention belongs to the field of building materials, and particularly relates to a method for manufacturing cement clinker by using chromium-containing waste residues of a chromium salt factory as a cement mineralizer.

Background

At present, because the chromite is generally oxidized and roasted by calcium-containing alkali in China, the problem of headache is inevitable, and how to reasonably treat a large amount of chromium-containing waste residues generated in production is solved. In the past, there have been some units such as Shandong province Jinan Yuxing chemical general factory which used chromium slag to make iron (Wang Zhi, Huzhuang, chromium slag comprehensive treatment and application in iron-making solvent, chromium salt industry, national chromium salt cooperative group, 2000, No. 1), and chromium slag to replace part of limestone to make cement (patent name: method for producing cement clinker by using chromium salt slag to replace part of limestone, inventor: Hurongliang, publication No. CN1098075A), brick making from chromium slag, calcium magnesium phosphate fertilizer making from chromium slag, and dry detoxification and wet detoxification (Wai Kan Bing et al, weaving chromium salt production process, chemical industry publishing Co., 1988) to treat chromium slag, and all these methods have not succeeded in a complete sense. Or the treatment cost of the chromium slag is high, and the treatment cost of each ton of chromium slag is as high as more than 600 yuan; or secondary pollution is generated after the chromium slag is treated, and the concentration of hexavalent chromium far exceeds 8 ppm. These methods are difficult to popularize.

Disclosure of Invention

The present invention aims at providing a method for producing cement clinker by using chromium slag as a cement mineralizer, which avoids the defects of the prior art, can completely meet the requirements of the building industry, does not need to change the process flow, can reduce the production cost of cement, and eliminates the pollution of chromium slag.

The invention mainly comprises the following steps:

A. adding mineralizer chromium slag into the raw material batching system.

B. Homogenizing raw materials, pelletizing and calcining in a kiln.

C. The clinker is crushed, and the mixture of gypsum, water slag and catalytic stabilizer such as ferrous sulfate, sodium sulfite or sodium thiosulfate is fed into a cement mill to obtain the powdered cement product.

The method comprises the following specific steps:

a. the chromium slag, anthracite, clay, iron powder and mineralizer of chromium slag are mixed by microcomputer to prepare powdery black raw material. The addition amount of the chromium slag mineralizer is 0.1-10%.

b. The raw material is homogenized by a homogenizing chamber, added with water to form balls, and then placed in a kiln for calcination. The calcination temperature is controlled to be 1100-1600 ℃, hexavalent chromium is reduced to three prices by CO generated by incomplete combustion during calcination, the reaction time is 25-60 min, and therefore the purpose of detoxification is achieved, and the reaction formula is as follows:

the toxicity of the hexavalent chromium is relieved through the reaction, and the reduction rate of the chromium slag reaches up to 99.1 percent, thereby achieving the expected purpose.

c. After being crushed by a crusher, the cement clinker obtained by roasting, gypsum, water granulated slag and a catalytic stabilizer such as ferrous sulfate or sodium sulfite or sodium thiosulfate are mixed by a mixing system and then enter a cement mill, wherein the adding amount of the catalytic stabilizer is 0.01-0.1%, and finally a cement finished product is obtained.

Compared with the prior art, the invention has the following advantages:

1. the added chromium slag is used as a mineralizer, so that two minerals of C2S and C4AF are brought into the raw material to play a role of seed crystal; in addition, MgO brought by the chromium slag helps to melt, so that the temperature of a liquid phase generated during clinker calcination is reduced from 1350-1450 ℃ to 1300-1400 ℃, the heat distribution ratio of the clinker is reduced, and raw coal can be saved by 10-20% per ton of clinker.

2. The chromium slag is added as a mineralizer, Cr2O3 in the chromium slag plays a role in catalyzing C2S to absorb free CaO, so that the generation amount of C3S is increased, and meanwhile, the content of the free CaO in clinker is greatly reduced, so that the clinker quality is good, and the mechanical strength can be increased by 6-10 MPa.

3. The chromium slag is added as a mineralizer, so that the easy burning property of clinker is improved, the material ignition speed is high, the bottom fire is stable, the hourly output of the vertical kiln can be improved by 15-20%, and the power consumption of per ton of clinker is reduced by 6-8 ℃.

4. The setting time of the cement clinker fired by adding the chromium slag as the mineralizer can be shortened by 30-50 min

5. The chromium slag is added as a mineralizer, so that the grindability of the clinker is improved.

6. The cement prepared by adding the catalytic stabilizer has high early strength, stable stability, no yellowing of trivalent chromium and good color.

Detailed description of the preferred embodiments

Examples of which are further described below:

example 1:

a. 100 g of limestone, 21.5 g of clay, 3.3 g of iron powder, 14.9 g of anthracite and 2.1 g of mineralizer chromium slag are ground and mixed evenly.

b. Adding 15 g of water into the black raw material, stirring to form balls, putting the balls into a 500ml white jade crucible, covering the crucible with a cover, and then putting the crucible into a muffle furnace at 1400 ℃ for calcination for 30 min. Discharging the clinker and cooling.

c. After the clinker is crushed by a crusher, 2.5 g of gypsum, 2 g of water granulated slag and 0.05 g of ferrous sulfate are added, and the mixture is uniformly mixed and ground to obtain a finished product.

d. And (3) a finished product physical and chemical inspection result: the specific surface area is 305m2/Kg, the stability is qualified, the initial setting time is 90min, the final setting time is 155min, the breaking strength is 6.2MPa/3d, 8.2MPa/28d, the compressive strength is 36MPa/3d, 58.6MPa/28d, and the water-soluble hexavalent chromium is 2.0 ppm.

Example 2: the procedure of example 1 was repeated except that:

a. mineralizer chromium slag 2.8 g.

b. The muffle furnace temperature is 1350 ℃ and the time is 35 min.

c. 0.06 g of sodium sulfite.

d. And (3) a finished product physical and chemical inspection result: the specific surface area is 306m2/Kg, the stability is qualified, the initial setting time is 85min, the final setting time is 150min, the flexural strength is 6.6MPa/3d and 8.6MPa/28d, the compressive strength is 38MPa/3d and 61MPa/28d, and the water-soluble hexavalent chromium is 2.5 ppm.

Example 3: the procedure of example 1 was repeated except that:

a. mineralizer chromium slag 4.9 g.

b. The muffle furnace is at 1400 ℃ for 40 min.

c. 0.07 g of sodium thiosulfate.

d. And (3) a finished product physical and chemical inspection result: the specific surface area is 300m2/Kg, the stability is qualified, the initial setting time is 70min, the final setting time is 150min, the flexural strength is 6.4MPa/3d, 8.4MPa/28d, the compressive strength is 37.5MPa/3d, 60.3MPa/28d, and the water-soluble hexavalent chromiumis 2.5 ppm.

Claims

1. A method for preparing cement clinker by using chromium slag as a mineralizer is characterized by comprising the following steps:

a. adding chromium slag as a mineralizer into the cement raw material, wherein the weight ratio of the chromium slag to the raw material is 0.1-10%;

b. placing the raw material added with the mineralizer chromium slag into a kiln for calcination, wherein the reaction temperature is 1100-1600 ℃, and the reaction time is 25-60 min;

c. adding a catalytic stabilizer into the product obtained in the step b, wherein the addition amount of the catalytic stabilizer is 0.01-0.1% of the weight of the product obtained in the step b; the catalytic stabilizer is ferrous sulfate, sodium sulfite or sodium thiosulfate.

2. The method for preparing cement clinker by using chromium slag as mineralizer according to claim 1, which is characterized by comprising the following steps: wherein the kiln is a rotary kiln or a vertical kiln.