CN101723608A - Method for preparing travertine gelled material - Google Patents

Abstract

The invention discloses a method for preparing travertine gelled material, belonging to the technical fields of environmental protection and resource integrated utilization. The method comprises: mixing tailings and red mud to be ground into material cakes, material blocks, material balls or material powder which are sent into an alteration reactor for hydrothermal alteration reaction; controlling the temperature of the hydrothermal alteration reaction to be 200-900 DEG C and the reaction time to be 0.6-800min; and mixing and grinding the material pretreated by the hydrothermal alteration reaction, cement clinker, blast furnace water-granulated slag, plaster and diagenetic agent, and obtaining the travertine gelled material. By utilizing salt substances and volatile matter which are contained in the red mud for carrying out hydrothermal alteration on the tailings, the method realizes controlling waste by waste, simultaneously changes the tailings and the red mud into valuables, and reduces the damage for the ecological environment caused by stack of the tailings and the red mud; the produced travertine can be used as high quality cement on multiple occasions, but the production cost of the travertine can be reduced by 20-50% compared with cement; and the load of the environment in the production process is reduced by 50-80% compared with cement.

Description

A kind of method for preparing gelatinous cementitious material

technical field

The invention belongs to the technical field of environmental protection and resource comprehensive utilization, and in particular relates to a method for preparing gelatinous cementitious materials.

Background technique

Tailings are one of the largest solid wastes in my country. At present, the total annual output of tailings in my country is 600 million tons, of which 500 million tons are iron tailings, and the rest are non-ferrous metal tailings, precious metal tailings and non-metallic tailings. The cumulative stockpiles of tailings in my country are 6 billion tons. Except for a few skarn-type iron ore tailings and some non-metallic ore tailings, the sum of SiO2 and Al2O3 in most iron ore tailings, non-ferrous metal tailings and precious metal tailings is greater than 50%, so It belongs to the high silicon aluminum system. Such a large amount of tailings stockpiles not only occupies a large amount of farmland, mountains and rivers, causing serious damage to the environment and ecology, but also causes dam failures due to overloading of tailings ponds or poor management, which brings great harm to people's lives and properties. to huge losses, and catastrophic environmental accidents. There have been a large number of patent applications for the preparation of cement-like cementitious materials with high calcium system by using tailings at home and abroad. Chinese Patent Publication No. 200310109672 relates to a method for producing cement or cement products from metal tailings (skarn), which discloses adding 10 to 35% metal tailings (skarn) as a mixture to produce cement and It is a method of partially replacing cement to produce cement products, but still continues the basic manufacturing process of traditional high-calcium system cement. Chinese Patent Publication No. 011302336 relates to a Portland cement clinker, which discloses a method for producing cement clinker with limestone, iron tailings, fly ash, and boiler bottom slag as raw materials. A manufacturing method of traditional high-calcium Portland cement. Chinese Patent Publication No. 96109194 relates to a method for recovering iron ore tailings slag, in which the tailings are converted into FeCO ₃ into Fe ₃ O ₄ by calcining the tailings at 400-800°C and then magnetically separated to recover iron, while the CaCO in the tailings ₃ and MgCO ₃ are converted into CaO and MgO, and kaolinite is transformed into metakaolinite, so the remaining part after magnetic separation has hydraulic activity and is used as raw material for the production of low-grade cement. The technology for producing low-grade cement disclosed in the invention follows the idea of using burnt clay as the cement active admixture in traditional cement. Chinese Patent Publication No. 92106479 relates to the production of cement clinker by using copper tailings, wherein 5-9% of copper tailings, 71-80% of limestone, 4.5-6.5% of clay, and 6% of anthracite are used as ingredients to produce cement clinker. Among them, the main function of copper tailings is to replace part of the clay, provide SiO ₂ , and act as a mineralizer to a certain extent. Its technical route still follows the technical route of the traditional Portland cement high-calcium system.

The patent for invention with the publication number 02158190 "Concrete Binary Wet Cement and Its Uses" describes the method of using a large amount of waste slag wet method to prepare gel cementitious materials, but does not introduce the method of mixing tailings and red mud first and then The technology of hydrothermal alteration pretreatment also does not include the technology of producing concrete with tailings and red mud as the main raw materials.

The world discharges about 60 million tons of red mud every year. In my country, the five major alumina plants of Chinalco alone discharge 4 million tons of red mud every year, and the cumulative stock of red mud is as high as 50 million tons, while its utilization rate is only 15 million tons. %about. At present, most alumina factories at home and abroad transport red mud to storage yards, build dams for wet storage, and rely on natural sedimentation to separate and recycle part of the lye. This method easily causes a large amount of waste lye to penetrate into nearby farmland, resulting in soil alkalization , Swamp, pollution of surface and groundwater sources. Another method is to store the red mud after drying and dehydration. The Pingguo Aluminum Company in my country mainly adopts the dry storage method. Although the stockpiling volume is reduced and the stockpiling height can be increased, the processing cost increases and it still needs to occupy At the same time, there is sufficient rainfall in the south, which can easily cause land alkalization and water pollution. In short, red mud stockpiling not only requires a certain amount of capital construction costs, but also takes up a lot of land, pollutes the environment, and makes many available components in red mud not be used rationally, resulting in secondary waste of resources, which seriously hinders the aluminum industry. of sustainable development.

Most of the red mud in my country's alumina plants is stockpiled by means of flat platforms, valley dams, and depression filling, and most of them have not taken effective measures. For example, Shandong Aluminum Company adopts the method of flat land and high platform, and the red mud stockyard has stockpiled more than 18 million tons of red mud, and the dam height is 50m. Since no anti-seepage measures have been taken, the permeability coefficient of red mud waste liquid is as high as 1.22×10 ^-4 ~5.86×10 ^-5 cm/s, polluting 200~700m of groundwater, causing permanent alkalization of groundwater in this area, which is of great concern to the The regional ecological environment has caused serious damage, which has always been a "heart disease" for the company and even Zibo City, which has seriously plagued the sustainable development of the aluminum industry. Therefore, the comprehensive utilization of red mud has become an urgent problem to be solved in the aluminum smelting industry.

Although it is theoretically possible to recover high-priced elements from red mud, if the recycled red mud residue does not take other utilization measures, the social problems caused by red mud stockpiling will not be alleviated. In order to fundamentally eliminate the hazards of red mud, a large number of experimental studies have been carried out on other comprehensive utilization of red mud at home and abroad. Such as the production of glass, plastic packing, anti-seepage materials, cement, paving, etc., but most of them have not been put into production and operation at present, and the usage of red mud is still very low.

The most studied abroad is the Bayer process red mud. Because of its high content of iron oxide, the former Soviet Union, Germany, the United States, Japan, Hungary and other countries have all conducted red mud ironmaking experiments. In the former Soviet Union, red mud was used as iron raw material to mix cement raw materials, and the proportion could reach 14%. Japan’s Mitsui Alumina Co., Ltd. cooperated with cement plants, and cement clinker could use red mud at 5-20kg/t. Spain’s Lugao alumina The factory tested the production of wall bricks from Bayer process red mud and fly ash. At present, many foreign experts are devoted to the research on the application of red mud adsorbent to purify wastewater and hydrogen sulfide waste gas. However, due to technical and economical reasons, the above studies are mostly in the experimental stage, and the current utilization level of Bayer process red mud is still relatively low.

Since the first alumina plant was built in my country in 1954, the research on the comprehensive utilization of red mud has never stopped. In the early 1960s, Shandong Aluminum Factory built a national large-scale cement plant aimed at comprehensive utilization of red mud. However, due to the high alkali content in red mud, the fluidity of red mud slurry decreased after reducing the alkali content of red mud. can be used in production.

The invention patent "A method for producing cement by using red mud (CN1613809)" discloses a method for producing cement by using red mud, and relates to a method for producing cement by using waste red mud produced by alumina, especially to eliminate The method of cementing and hardening when storing ingredients after alkali. Including the use of atmospheric calcium oxide hydration method for dealkalization of red mud, storage of ingredients and conventional cement production process, which is characterized in that the red mud after dealkalization and filtration is cooled to 5 ° C ~ 55 ° C and then enters the storage of ingredients for cement production process. Surface treatment with sulfonate additives.

In the invention patent of a method of using red mud to produce cement (CN1613809), it is mentioned that it can effectively prevent the hardening of dealkalized red mud and cement raw material slurry, so that the amount of red mud in the cement production process is reduced from the current 15%. Increasing it to more than 50% plays an important role in the comprehensive utilization of waste red mud in the alumina production process, environmental protection and reduction of cement production costs.

The invention patent "A method for preparing sulphoaluminate cement from red mud (CN1837121)" discloses a preparation method of sulphoaluminate cement using alumina industrial waste slag red mud as the main raw material and its preparation method. The formula is mainly based on 26 %~41% of the red mud partially replaces some of the aluminum and calcium raw materials used in the production of conventional sulphoaluminate cement, and completely replaces the silicon and iron raw materials. After grinding to a certain fineness, through the design of C in the cement clinker ₄ A ₃ S, C ₂ S, C ₄ AF and other main minerals, prepared with bauxite, limestone, gypsum and other ingredients to prepare sulphoaluminate cement. The method prepares sulphoaluminate cement, has high direct utilization rate of red mud, does not need to improve the traditional sulphoaluminate cement production process, has good clinker burnability, fast hardening speed, high early strength, and enhanced and stable later strength. Performance tests show that the mechanical strength of sulphoaluminate cement prepared from red mud is better than that of commercially available 425 grade rapid hardening sulphoaluminate cement.

The method of hydrothermal alteration was invented based on the principle of hydrothermal alteration in geological processes. Hydrothermal alteration is ubiquitous in geological processes and is the most important effect of changes in mineral composition in the earth's crust. In hydrothermal alteration, the volatile group has the characteristics of strong polarity and high activity at the moment when it is released. It acts on the surface of mineral particles, causing severe damage to the surface lattice, increasing bond breaking, and increasing reactivity. It lays the foundation for dissolution, depolymerization and migration. The strength of this hydrothermal alteration can be greatly improved under the combined synergistic effect of multi-component salts.

Contents of the invention

The object of the present invention is to provide a kind of method for preparing gelatinous cementitious material, it is characterized in that, the method preparation step is,

(1) Prepare the mixed material, mix 60-90% tailings with 10-40% red mud according to the weight percentage, the mixing mode is wet mixing or dry mixing, when the wet mixing mode is adopted, after the mud is out of the mill Forced dehydration treatment should be carried out to control its moisture content at 0.1-20%, and then the dehydrated mud should be made into cakes, lumps, balls or powder, and then sent into the alteration reactor for hydrothermal alteration reaction ; When the dry mixing mode is used, the obtained dry powder is added to 0.1-10% of the weight of the mixed material to make a cake, material block, material ball or material powder;

(2) The mixed material undergoes hydrothermal alteration reaction in the high temperature reactor, the temperature of hydrothermal alteration reaction is 200-900°C, and the reaction time is 0.6-800min;

(3) 50-90% of materials pretreated by hydrothermal alteration reaction, 0.1-29% of cement clinker, 0-30% of blast furnace water-quenched slag, 0-8% of gypsum, and 0.1-5% of diagenetic agent according to weight percentage % Mixing and grinding, the final mixed material should be ground to a specific surface area of 380-780m ² /kg to obtain the gelatinous cementitious material.

The equipment used for the mixing is a ball mill or a forced mixer. When a ball mill is used as a mixing device, the input particle size is ≤2000 μm, and the output particle size is ≤100 μm. 10 to 200 minutes.

The high temperature reactor is a continuous kiln or a batch kiln, a rotary kiln or a tunnel kiln, a chain kiln, a drawer kiln, a shuttle kiln or a kiln in which the material layer is heated in a fluidized state.

The gypsum includes natural anhydrite, dihydrate gypsum, desulfurized gypsum, phosphogypsum or industrial waste containing CaSO ₄ .

The diagenetic agent is Ningshi A diagenesis agent or Ningshi C diagenesis agent, Ningshi A diagenesis agent is used in the formula with cement clinker content ≥ 5%, and Ningshi C diagenesis agent is used for cement clinker content <5% % of the formula.

The beneficial effects of the present invention are:

① Utilize the salts and volatiles contained in the red mud to carry out hydrothermal alteration on the tailings, realize waste treatment by waste, turn waste into treasure at the same time, and reduce the impact of tailings and red mud accumulation on the ecology damage to the environment;

②The produced concrete can be used as high-grade cement in many occasions, but its production cost can be reduced by 20-50% compared with that of cement;

③ The environmental load of the production process can be reduced by 50-80% compared with the production of cement.

Detailed ways

The present invention utilizes red mud containing a large amount of NaCl, NaOH, 2CaO.SiO ₂ .nH ₂ O, CaOCO ₃ , Ca(OH) _2, etc., mixes red mud with tailings and heats them to volatilize various substances in red mud The components form hydrothermal alteration on the tailings surface, while the red mud itself is self-altered. After pretreatment, a large proportion of tailings and red mud (up to 70%) can be used, with little (below 30%) or no cement clinker, and the production of gelatinous cementitious materials with high-grade cement performance.

The present invention will be further described below in conjunction with accompanying drawing:

Example 1

A method for preparing gelatinous cementitious material, the preparation steps of the method are,

(1) Prepare mixed materials, mix 60% tailings and 40% red mud by weight percentage, tailings particle size ≤ 100 μm, red mud particle size ≤ 100 μm, the equipment used for mixing is a forced mixer, and the mixing mode is dry mixing , the time is 100min, and the obtained mixed dry powder is added with 6% water to make a block.

(2) The mixed block undergoes hydrothermal alteration reaction in the tunnel kiln, the temperature of hydrothermal alteration reaction is 750°C, and the reaction time is 200min;

(3) Mix 65% of materials pretreated by hydrothermal alteration reaction, 0.1% of cement clinker, 30% of blast furnace water-quenched slag, and 4.9% of diagenetic agent C (purchased from Lanzi Technology Co., Ltd.) by weight percentage Grinding, the final mixed material should be ground to a specific surface area of 540m ² /kg to obtain a gelatinous cementitious material.

After homogenization and inspection, the obtained mixed powder can be used as the finished gelatin cementitious material. The strength and stability of the material are tested according to the GB175-1999 standard. The compressive strength is 21.8MPa in 3 days and 53.1Mpa in 28 days; The flexural strength was 4.9MPa in 3 days and 9.2MPa in 28 days; the stability test was qualified in both 3 days and 28 days.

Example 2

A method for preparing gelatinous cementitious material, the preparation steps of the method are,

(1) Prepare mixed materials, mix 70% gold tailings with 30% red mud by weight percentage, gold tailings particle size≤800μm, red mud particle size≤1000μm, wet mixing and grinding in a ball mill for 50min, wet The ground mud is dehydrated to control its water content at 10%, and then the dehydrated mud is made into pellets;

(2) The mixed material balls undergo hydrothermal alteration reaction in the rotary kiln, the temperature of the hydrothermal alteration reaction is 800°C, and the reaction time is 56 minutes;

(3) 69% of materials pretreated by hydrothermal alteration reaction, 10% of cement clinker, 15% of blast furnace water-quenched slag, 5% of natural anhydrous gypsum, diagenetic agent A (purchased from Lanzi) Technology Co., Ltd.) 1%, mixed and pre-ground blast furnace water-quenched slag, cement clinker and diagenetic agent A to a specific surface area of 390m ² /kg, and then mixed with the mixed material and natural dihydrate gypsum after hydrothermal alteration reaction Mix and grind until the specific surface area is 580m2/kg to obtain gelatinous cementitious material.

After homogenization and inspection, the obtained mixed powder can be used as the finished gelatin cementitious material. The strength and stability of the material are tested according to the GB175-1999 standard. The compressive strength is 26.1MPa in 3 days and 51.2MPa in 28 days. The flexural strength was 4.1MPa in 3 days and 8.9MPa in 28 days, and the stability was qualified in both 3-day and 28-day tests.

Example 3

A method for preparing gelatinous cementitious material, the preparation steps of the method are,

(1) Prepare the mixed material, mix 85% of copper tailings and 15% of red mud by weight percentage, the particle size of gold tailings is ≤300 μm, and the particle size of red mud is ≤1500 μm, and wet mixing and grinding in a ball mill for 100 minutes, after wet grinding The mud is dehydrated to control its water content at 2%, and then the dehydrated mud is made into powder;

(2) The mixed material powder undergoes hydrothermal alteration reaction in the cyclone powder reactor (one of the kilns in which the material layer is heated in a fluidized state), and the temperature of the hydrothermal alteration reaction is 800°C , the reaction time is 1min;

(3) 65% of materials pretreated by hydrothermal alteration reaction, 10% of cement clinker, 15% of blast furnace water-quenched slag, 9% of phosphogypsum, and rock-forming agent A (purchased from Lanzi Technology Co., Ltd. Company) 1% mixing and grinding, the blast furnace water-quenched slag, cement clinker, and rock forming agent A are mixed and pre-ground to a specific surface area of 390m ² /kg, and then mixed and ground with the altered mixed material and phosphogypsum to The specific surface area is 580m ² /kg, and the gelatinous cementitious material is obtained.

After homogenization and inspection, the obtained mixed powder can be used as the finished gelatin cementitious material. The strength and stability of the material are tested according to the GB175-1999 standard. The compressive strength is 25.5MPa in 3 days and 50.2MPa in 28 days. The flexural strength was 4.8MPa in 3 days and 8.9MPa in 28 days, and the stability was qualified in both 3-day and 28-day tests.

Example 4

A method for preparing gelatinous cementitious material, the preparation steps of the method are,

(1) Prepare the mixed material, mix 75% sedimentary hematite tailings with 25% red mud by weight percentage, the tailings particle size of sedimentary hematite is ≤300 μm, and the red mud particle size is ≤100 μm , wet mixing and grinding in a ball mill for 20 minutes, dehydrating the wet-milled mud to control its moisture content at 8%, and then making the dehydrated mud into blocks;

(2) The mixed block undergoes hydrothermal alteration reaction in the tunnel kiln, the temperature of hydrothermal alteration reaction is 720°C, and the reaction time is 700min;

(3) 79% of materials pretreated by hydrothermal alteration reaction, 0.2% of cement clinker, 16% of blast furnace water-quenched slag, and 4.8% of condensate C diagenetic agent (purchased from Lanzi Technology Co., Ltd.) were combined by weight percentage Mix and grind until the specific surface area is 530m ² /kg to obtain gelatinous cementitious material.

After homogenization and inspection, the obtained mixed powder can be used as the finished gelatin cementitious material. The strength and stability of the material are tested according to the GB175-1999 standard. The compressive strength is 21.5MPa in 3 days and 46.1MPa in 28 days. The flexural strength was 4.0MPa in 3 days and 8.7MPa in 28 days, and the stability was qualified in both 3-day and 28-day tests.

Claims (5)

1. a method for preparing gelatinous cementitious material, is characterized in that, the method preparation step is, (1) Prepare the mixed material, mix 60-90% tailings with 10-40% red mud according to the weight percentage, the mixing mode is wet mixing or dry mixing, when the wet mixing mode is adopted, after the mud is out of the mill Forced dehydration treatment should be carried out to control its moisture content at 0.1-20%, and then the dehydrated mud should be made into cakes, lumps, balls or powder, and then sent into the alteration reactor for hydrothermal alteration reaction ; When the dry mixing mode is used, the obtained dry powder is added to 0.1-10% of the weight of the mixed material to make a cake, material block, material ball or material powder; (2) The mixed material undergoes hydrothermal alteration reaction in the high temperature reactor, the temperature of hydrothermal alteration reaction is 200-900°C, and the reaction time is 0.6-800min; (3) 50-90% of materials pretreated by hydrothermal alteration reaction, 0.1-29% of cement clinker, 0-30% of blast furnace water-quenched slag, 0-8% of gypsum, and 0.1-5% of diagenetic agent according to weight percentage % Mixing and grinding, the final mixed material should be ground to a specific surface area of 380-780m ² /kg to obtain the gelatinous cementitious material. 2. a kind of method for preparing gelatinous cementitious material according to claim 1, is characterized in that, the equipment used for described mixing is ball mill or forced mixer, when adopting ball mill as mixing equipment, feed particle size≤2000 μ m, The output particle size is ≤100μm. When the forced mixer is used as the mixing equipment, the input particle size is ≤100μm, and the time is 10-200min. 3. A kind of method for preparing gelatinous cementitious material according to claim 1, is characterized in that, described high-temperature reactor is continuous kiln or intermittent kiln, is rotary kiln or tunnel kiln, chain furnace , drawer kiln, shuttle kiln or kiln where the material layer is fluidized and heated. 4. a kind of method for preparing gelatin cementitious material according to claim 1, is characterized in that, described gypsum comprises natural anhydrous gypsum, dihydrate gypsum, desulfurized gypsum, phosphogypsum or containing _CaSO Industrial waste . 5. A kind of method for preparing gel cementitious material according to claim 1, is characterized in that, described diagenetic agent is diagenetic agent of condensate A or diagenetic agent of condensate C, and diagenetic agent of condensate A is used for cement curing In the formula with the content of cement clinker ≥ 5%, the diagenetic agent C is used in the formula with the content of cement clinker < 5%.