CN112110738A

CN112110738A - Method for preparing high-alumina refractory material from aluminum ash

Info

Publication number: CN112110738A
Application number: CN202011014292.6A
Authority: CN
Inventors: 谭宏斌; 马小玲; 董发勤; 杨飞华; 李玉香; 张吉秀; 李芳�; 王进明; 邓秋林; 王进; 贺小春
Original assignee: Southwest University of Science and Technology
Current assignee: Southwest University of Science and Technology
Priority date: 2020-09-24
Filing date: 2020-09-24
Publication date: 2020-12-22

Abstract

The patent discloses a method for preparing a high-alumina refractory material by using aluminum ash, which is characterized in that the aluminum ash is washed by water to remove soluble salt, and then is filtered and dried to obtain filter residue; adding concentrated sulfuric acid into the filter residue, uniformly stirring in a physical field stirrer, filtering and washing to obtain purified residue; and forming and sintering the purified slag to obtain the high-alumina refractory material. The method has low production cost and high efficiency, and realizes high-quality cyclic utilization of resources.

Description

Method for preparing high-alumina refractory material from aluminum ash

Technical Field

The invention relates to the field of resource utilization of non-ferrous solid waste, in particular to resource application of aluminum ash.

Background

Aluminum ash is the product of the aluminum fusion casting process. The composition and content of the aluminum ash can be greatly different according to different raw materials and production purposes of aluminum casting. The method is characterized in that electrolytic aluminum liquid is used for producing aluminum ash produced by remelting aluminum ingots, the aluminum ash accounts for about 1.1% of the ingot output, the components are relatively simple and stable, and the aluminum ash mainly comprises metal aluminum, aluminum oxide, aluminum nitride, chloride (sodium chloride and potassium chloride) and electrolytes (sodium fluoride, calcium fluoride, cryolite and the like), wherein the aluminum accounts for about 40% -50%, and the aluminum oxide accounts for about 30% -40%; in addition to metallic aluminum, aluminum oxide, aluminum nitride, chloride salts and electrolytes, other elements and oxides with various quantities and types exist in aluminum ash produced in the production of aluminum alloy products [ Liu Zhan, Liang Xuanfeng, formation and evolution of each component in aluminum ash are briefly analyzed [ J ]. Hunan nonferrous metals, 2019, 35 (5): 58-60].

The aluminum particles contained in the aluminum ash have the characteristics of large surface area and high activity, and are easy to react to generate hydrogen when meeting water or in a humid environment; the aluminum nitride in the aluminum ash generates ammonia gas when meeting water. Hydrogen and ammonia are both reducing gases, and are easy to explode when meeting oxygen and open fire, and the ammonia has pungent smell and is one of the main reasons that the aluminum ash has environmental hazard. In addition to having reaction activity, leaching toxicity tests find that the dissolved fluorine ions in the detected aluminum ash sample exceed the standard, the excessive discharge of the fluorine ions has serious harm to water, soil, animals and plants, and the removal and harmless disposal of fluorine are the important problems to be solved in the comprehensive aluminum ash disposal technology [ pyroshiwei, bangwei, billow, and the like ]. 19-21].

Generally, the aluminum ash can be divided into primary aluminum ash and secondary aluminum ash according to the content of metallic aluminum in the aluminum ash. The aluminum slag taken out of the smelting furnace is called primary aluminum ash, is grayish white in appearance, is mainly a mixture consisting of metal aluminum and aluminum oxide, has the aluminum content of 15-70 percent, and is also called white aluminum ash; the secondary aluminum ash is waste after the primary aluminum ash is extracted with metal aluminum, the main components are aluminum oxide, aluminum nitride, metal aluminum, salts and other components, and the secondary aluminum ash is solidified into a block shape and is also called as a 'salt cake' (Li Shuai, Liuwan super, Liuzhongkai, and the like). 25-29].

The used aluminium ash of this patent is the secondary aluminium ash after the metal aluminium is drawed to the first aluminium ash, to the secondary aluminium ash can not the high-valued utilization scheduling problem, this patent provides the method of aluminium ash preparation high aluminium matter refractory material, promotes the high-valued utilization of aluminium ash.

Disclosure of Invention

Compared with the prior art, the method can improve the added value of products, realize the cyclic utilization of resources and have remarkable economic and social benefits.

A method for preparing a high-alumina refractory material from aluminum ash comprises the following steps:

washing aluminum ash with water to remove soluble salt, filtering, and drying to obtain filter residue; adding concentrated sulfuric acid into the filter residue, uniformly stirring in a physical field stirrer, filtering and washing to obtain purified residue; and forming and sintering the purified slag to obtain the high-alumina refractory material.

The concentration of the concentrated sulfuric acid is 70-98%.

The physical field stirrer is provided with one of ultrasonic waves and microwaves.

The physical field stirrer is also provided with a mechanical stirring device, and a grinding medium in the device is one of alumina balls and zirconia balls.

The sintering temperature is 800-1300 ℃.

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

washing the aluminum ash with water to remove soluble salts, wherein the adopted washing method is three-stage countercurrent washing, namely the third-stage washing water is tap water or circulating water, the washed filtrate is used as second-stage washing water, and the filtrate after the second-stage washing is used as first-stage washing water; evaporating and concentrating the filtrate after the first stage of washing to obtain salt, and recycling; and condensing steam generated by evaporation to obtain circulating water for the third washing stage, so that the water is recycled. The filtration adopts one of filter pressing and vacuum filtration.

Adding concentrated sulfuric acid into the filter residue, wherein the concentrated sulfuric acid can passivate metal aluminum and aluminum nitride in the filter residue, the concentrated sulfuric acid can react with impurities such as calcium fluoride in the filter residue to obtain hydrogen fluoride gas and sulfate, and removing the sulfate in the washing process to obtain the purified residue. The phases of the purification slag are metallic aluminum, aluminum oxide and aluminum nitride. The waste water generated by washing is neutralized by lime or carbide slag, water is recycled, and the filtered precipitate is used as a raw material of cement.

The physical field stirrer is provided with one of ultrasonic waves and microwaves, and both the two physical fields can generate physical action on filter residues and can promote the reaction of impurities and sulfuric acid.

Grinding media in the physical field stirrer are alumina balls and zirconia balls, the grinding media are added into the physical field stirrer, and the grinding media have a grinding effect on filter residues in the movement process, so that filter residue particles are separated favorably, the coated impurities are exposed, and the reaction with sulfuric acid is facilitated.

In the calcining process after the purified slag is formed, the residual metal aluminum is oxidized into aluminum oxide, so that the density of the product is increased, and the strength of the product is improved. The aluminum nitride has stronger heat conduction capability and is left in the high-alumina refractory material as a second phase, so that the thermal shock performance of the product is improved. In addition, the purification slag has the characteristics of small particle size, high activity and low calcination temperature of the high-alumina refractory material.

Detailed Description

The present invention will be described in further detail with reference to specific examples.

Washing aluminum ash with water to remove soluble salt, filtering, and drying to obtain filter residue; adding concentrated sulfuric acid into the filter residue, uniformly stirring in a physical field stirrer, filtering and washing to obtain purified residue; and forming and sintering the purified slag to obtain the high-alumina refractory material. The concentrated sulfuric acid concentration, physical field stirrer configuration and grinding media, sintering temperature are shown in table 1.

TABLE 1

The embodiments of the invention can be implemented and achieve the aim of the invention. The present invention is not limited to these examples.

Claims

1. The method for preparing the high-alumina refractory material by using the aluminum ash is characterized by comprising the following steps of: washing aluminum ash with water to remove soluble salt, filtering, and drying to obtain filter residue; adding concentrated sulfuric acid into the filter residue, uniformly stirring in a physical field stirrer, filtering and washing to obtain purified residue; and forming and sintering the purified slag to obtain the high-alumina refractory material.

2. The method for preparing the high-alumina refractory material from the aluminum ash as claimed in claim 1, wherein the concentration of the concentrated sulfuric acid is 70-98%.

3. The method for preparing the high-alumina refractory material from the aluminum ash according to claim 1, wherein the physical field stirrer is one of ultrasonic wave and microwave.

4. The method for preparing the high-alumina refractory material from the aluminum ash according to claim 1, wherein the physical field stirrer is further provided with a mechanical stirring device, and the grinding medium in the device is one of alumina balls and zirconia balls.

5. The method as claimed in claim 1, wherein the sintering temperature is 800-1300 ℃.