阅读说明：本技术 一种煤基球团用复合粘结剂及其使用方法 (Composite binder for coal-based pellets and use method thereof ) 是由 王赢博 王殿龙 王兴锋 崔金楠 李宗胜 常春林 陈媛媛 高源� 于 2020-12-04 设计创作，主要内容包括：本发明的目的是为了解决现有技术中作为球团粘结剂的常规膨润土和复合膨润土存在的问题,提供了一种煤基球团用复合粘结剂及其使用方法,属于冶金原料与预处理技术领域。本发明的复合粘结剂由以下组分按质量百分比组成：有机粘结剂8-12％,煤粉25-35％,除尘灰55-65％；其中有机粘结剂,由以下组分按质量百分比组成：腐殖酸钠45-65％,羧甲基纤维素钠30-40％,聚丙烯酰胺5-15％。本发明的粘结剂不含有膨润土,以替代膨润土或复合膨润土,改善球团质量,提高生球强度和爆裂温度,提高成品球抗压强度和全铁品位。产生高炉增产节焦,节能减排,降低氮氧化物,减少回转窑结圈,合理利用铁矿资源的良好效果。(The invention aims to solve the problems of conventional bentonite and composite bentonite serving as pellet binders in the prior art, provides a composite binder for coal-based pellets and a using method thereof, and belongs to the technical field of metallurgical raw materials and pretreatment. The composite binder comprises the following components in percentage by mass: 8-12% of organic binder, 25-35% of coal powder and 55-65% of dedusting ash; the organic binder comprises the following components in percentage by mass: 45-65% of sodium humate, 30-40% of sodium carboxymethylcellulose and 5-15% of polyacrylamide. The binder does not contain bentonite, replaces bentonite or composite bentonite, improves the quality of pellets, improves the green pellet strength and the bursting temperature, and improves the compressive strength and the total iron grade of finished pellets. The production of the blast furnace has the good effects of increasing the production, saving coke, saving energy, reducing emission, reducing nitrogen oxides, reducing the ring formation of the rotary kiln and reasonably utilizing iron ore resources.)

1. The composite binder for the coal-based pellets is characterized by comprising the following components in percentage by mass: 8-12% of organic binder, 25-35% of coal powder and 55-65% of dedusting ash;

the organic binder comprises the following components in percentage by mass: 45-65% of sodium humate, 30-40% of sodium carboxymethylcellulose and 5-15% of polyacrylamide.

2. The composite binder for coal-based pellets according to claim 1, wherein the specification of the pulverized coal is as follows: volatile components less than 20%, ash less than 12%, calorific value not less than 7000kcal/kg, and particle size-200 mesh accounts for 70-80%.

3. The composite binder for coal-based pellets according to claim 1, wherein the fly ash is derived from electric dust removal and cloth bag dust removal, TFe in the fly ash is 63.5-64.5%, and the fly ash contains no moisture, and the particle size of-200 meshes accounts for 90-95%.

4. The composite binder for the coal-based pellets as claimed in claim 1, wherein the viscosity of the sodium carboxymethyl cellulose is 800-1200 mpa-s, the moisture content is less than or equal to 10%, and the pH value is 6.5-9.5.

5. The preparation method of the composite binder for the coal-based pellets, which is disclosed by claim 1, is characterized in that a finished product is obtained by uniformly mixing the organic binder, the coal powder and the fly ash according to a proportion, wherein the granularity of the finished product is-200 meshes and is more than or equal to 90%.

6. The method for using the composite binder for coal-based pellets according to claim 1, wherein the binder for pellets is added to the water-containing iron ore concentrate powder to prepare green pellets when the pellets are produced; wherein, the adding amount of the composite binder is 1 to 1.2 percent of the total amount of the water-containing iron concentrate powder and the composite binder by mass percent.

Technical Field

The invention belongs to the technical field of metallurgical raw materials and pretreatment, and particularly relates to a composite binder for pellets and a use method thereof.

Background

At present, in the production of pellet ore in China, composite bentonite is always used as a binder, and the addition amount is generally about 1-1.2%. Because of the characteristics of the components, the bentonite brings certain harmful impurities, such as harmful elements of potassium, sodium and the like and SiO₂And the like, and also reduces the grade of the pellet. For iron works, theoretically, the grade of pellets is reduced by about 0.65% (the grade of fine powder is 65%) every time 1% of bentonite is added, and impurities are increased at the same time, so that the grade of iron-making raw materials entering a furnace is reduced, the fuel ratio is increased, and the cost is increased.

At present, a plurality of special pellet binders have been developed at home and abroad, and are all well applied in industry. However, the belt roasting of the pellets in foreign countries has no special requirement on the strength of the preheated pellets, and the preheated pellets bear the impact and rolling friction of the rotary kiln in the process mainly of the grate-rotary kiln in China. Otherwise, the dust in the kiln is too large to cause ring formation in the kiln, so that the normal production cannot be realized. And the domestic research mainly adopts a composite mode, namely the organic binder and the bentonite are compounded to meet the basic requirements of the rotary kiln on the pellets. However, this method does not fundamentally solve the problem of replacing bentonite.

Disclosure of Invention

The invention aims to solve the problems of conventional bentonite and composite bentonite serving as a pellet binder in the prior art, and provides a composite binder for coal-based pellets and a using method thereof. The production of the blast furnace has the good effects of increasing the production, saving coke, saving energy, reducing emission, reducing nitrogen oxides, reducing the ring formation of the rotary kiln and reasonably utilizing iron ore resources.

In order to achieve the purpose, the invention adopts the following technical scheme:

one of the technical schemes is that the composite binder for the coal-based pellets comprises the following components in percentage by mass: 8-12% of organic binder, 25-35% of coal powder and 55-65% of dedusting ash;

the organic binder comprises the following components in percentage by mass: 45-65% of sodium humate, 30-40% of sodium carboxymethylcellulose and 5-15% of polyacrylamide;

the coal powder has less than 20% of volatile components, less than 12% of ash, a calorific value of not less than 7000kcal/kg, and 70-80% of granularity-200 meshes;

the dedusting ash is derived from electric precipitation and cloth bag dedusting, the TFe in the dedusting ash is 63.5-64.5%, no water is contained, and the granularity of-200 meshes accounts for 90-95%;

the viscosity of the sodium carboxymethylcellulose is 800-1200mpa · s, the water content is less than or equal to 10 percent, and the pH value is 6.5-9.5.

The preparation method of the pellet composite binder comprises the following steps: and (3) uniformly mixing the organic binder, the coal powder and the dedusting ash according to the proportion to obtain a finished product, wherein the granularity of the finished product is-200 meshes and is more than or equal to 90%.

The second technical proposal is that the use method of the pellet composite binder comprises the following steps: when producing pellet, adding pellet binder into water-containing iron ore concentrate powder to prepare green pellets; wherein, the adding amount of the composite binder is 1 to 1.2 percent of the total amount of the water-containing iron concentrate powder and the composite binder by mass percent.

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

(1) the composite binder for the coal-based pellets can replace bentonite when producing the pellets, and meets the quality standard requirement of producing the coal-based pellets;

(2) the performance indexes of green strength, bursting temperature, finished ball compressive strength and the like of the pellets produced by adopting the composite binder meet the requirements of relevant standards;

(3) the invention can effectively improve the iron grade of the pellet, realize the yield increase and coke saving of the blast furnace, save energy, reduce emission and reasonably utilize iron ore resources, thereby improving the overall economic benefit of iron and steel enterprises.

Detailed Description

The invention will be further illustrated with reference to some specific embodiments.

In the following examples, the coal dust has less than 20% of volatile components, less than 12% of ash, a melting point of 1430 ℃ of ash, a calorific value of not less than 7000kcal/kg, and a particle size of 70-80% of-200 meshes; the dust removal ash TFe is 63.8%, and the dust removal ash TFe contains no moisture, and the granularity of-200 meshes accounts for 90-95%; the viscosity of the sodium carboxymethylcellulose is 800-1200mpa & s, the water content is less than or equal to 10 percent, and the pH value is 6.5-9.5.

Example 1

The composite binder for the coal-based pellets comprises the following components in percentage by mass: 8% of organic binder, 32% of coal powder and 60% of dedusting ash. Wherein the organic binder comprises 55% of sodium humate by mass; 35% of sodium carboxymethyl cellulose; 10% of polyacrylamide.

Example 2

The composite binder for the coal-based pellets comprises the following components in percentage by mass: 10% of organic binder, 30% of coal powder and 60% of dedusting ash. Wherein the organic binder comprises 55% of sodium humate by mass; 35% of sodium carboxymethyl cellulose; 10% of polyacrylamide.

Comparative example 1

The composite binder for the coal-based pellets comprises the following components in percentage by mass: 5% of organic binder; 30% of coal powder; 65% of dedusting ash. Wherein the organic binder comprises 55% of sodium humate by mass; 35% of sodium carboxymethyl cellulose; 10% of polyacrylamide.

Comparative example 2

The composite binder for the coal-based pellets comprises the following components in percentage by mass: 7.5% of organic binder; 30% of coal powder; and 62.5% of dedusting ash. Wherein the organic binder comprises 55% of sodium humate by mass; 35% of sodium carboxymethyl cellulose; 10% of polyacrylamide.

Comparative example 3

The composite binder for the coal-based pellets comprises the following components in percentage by mass: 12.5% of organic binder; 30% of coal powder; and 57.5% of dedusting ash. Wherein the organic binder comprises 55% of sodium humate by mass; 35% of sodium carboxymethyl cellulose; 10% of polyacrylamide.

Comparative example 4

The composite binder for the coal-based pellets comprises the following components in percentage by mass: 15.0% of organic binder; 30% of coal powder; dust removal ash 55.0%. Wherein the organic binder comprises 55% of sodium humate by mass; 35% of sodium carboxymethyl cellulose; 10% of polyacrylamide.

Comparative example 5

The composite binder for the coal-based pellets comprises the following components in percentage by mass: 10% of organic binder, 30% of coal powder and 60% of dedusting ash. Wherein the organic binder comprises 55% of sodium humate by mass; 45% of sodium carboxymethyl cellulose.

Comparative example 6

The composite binder for the coal-based pellets comprises the following components in percentage by mass: 10% of organic binder, 30% of coal powder and 60% of dedusting ash. Wherein the organic binder comprises 55% of sodium humate by mass; 45% of polyacrylamide.

Example 3

The composite binder for the coal-based pellets comprises the following components in percentage by mass: 12% of organic binder, 28% of coal powder and 60% of dedusting ash. Wherein the organic binder comprises 55% of sodium humate by mass; 35% of sodium carboxymethyl cellulose; 10% of polyacrylamide.

Example 4

The composite binder for the coal-based pellets comprises the following components in percentage by mass: 10% of organic binder, 35% of coal powder and 55% of dedusting ash. Wherein the organic binder comprises 55% of sodium humate by mass; 35% of sodium carboxymethyl cellulose; 10% of polyacrylamide.

Example 5

The composite binder for the coal-based pellets comprises the following components in percentage by mass: 10% of organic binder, 25% of coal powder and 65% of dedusting ash. Wherein the organic binder comprises 55% of sodium humate by mass; 35% of sodium carboxymethyl cellulose; 10% of polyacrylamide.

Example 6

The composite binder for the coal-based pellets comprises the following components in percentage by mass: 10% of organic binder, 30% of coal powder and 60% of dedusting ash. Wherein the organic binder comprises 45% of sodium humate by mass; sodium carboxymethylcellulose 40%; 15% of polyacrylamide.

Example 7

The composite binder for the coal-based pellets comprises the following components in percentage by mass: 10% of organic binder, 30% of coal powder and 60% of dedusting ash. Wherein the organic binder comprises 65 percent of sodium humate by mass; 30% of sodium carboxymethyl cellulose; 5% of polyacrylamide.

Application experiments

The composite binders and composite bentonite obtained in examples 1 to 7 and comparative examples 1 to 6 (control group, Jianping Huiyang chemical Co., Ltd.) were added to the water-containing iron ore concentrate powder to prepare green pellets, and the weight of the composite binder and the composite bentonite added was 1.1% of the total weight of the water-containing iron ore concentrate powder and the composite binder.

1. The resulting green pellet index is shown in table 1:

table 1, composite binders of examples 1 to 7 and comparative examples 1 to 6, and green pellet index prepared from composite bentonite

2. The green pellets are roasted to obtain finished pellets, and the compression strength of the finished pellets is compared in the following table 2 under the conditions that the preheating temperature is 950 ℃, the preheating time is 15min, the roasting temperature is 1250 ℃ and the roasting time is 30 min:

TABLE 2 compression strength comparison table for finished pellets

Group of	Compressive strength of finished ball (N/ball)
		Control group	2360
Example 1 group	2685
		Example 2 group	2591
Example 3 group	2482
		Example 4 group	2760
Example 5 group	2525
		Example 6 group	2580
Example 7 groups	2611

The technical indexes of the pellets in the laboratory require that the average falling strength of the green pellets is more than or equal to 4.5 times per pellet, and the average compressive strength of the green pellets is more than or equal to 12N. As can be seen from Table 1, the average falling strength and compressive strength of green pellets are gradually increased with the increase of the organic binder proportion in the composite binder by replacing bentonite with the composite binder for the coal-based pellets of 1.0-1.2%. The change of the proportion of the coal powder and the dedusting ash does not obviously influence the balling index; the sodium carboxymethylcellulose has a certain positive effect on the falling strength of the green pellets, and the polyacrylamide has a certain positive effect on the compressive strength of the green pellets. When the proportion of the organic binder in the composite binder is 5% and 7.5%, the falling frequency of the green pellets is respectively 3.2 and 4.3 times per green pellet, and the technical index requirements of the laboratory pellets cannot be met; when the mixture ratio is 12.5% and 15%, the bursting condition occurs. Therefore, the optimal proportioning range of the composite binder is 8-12% of organic binder, 25-35% of coal powder and 55-65% of dedusting ash, wherein the organic binder comprises the following components in percentage by weight: 45-65% of sodium humate; 30-40% of sodium carboxymethylcellulose; 5-15% of polyacrylamide. At this time, the average falling strength of the green pellets is improved by 1.7 times per pellet on average; the compressive strength is improved by 1.58N/ball. In addition, as can be seen from table 2, the compressive strength of the finished pellets after the composite binder is added is also obviously improved from 2300+ to 2700+ N/pellet, and the compressive strength of the finished pellets is the highest when the pulverized coal proportion is the most. The results show that the production of pellet ore by using the composite binder for coal-based pellets to replace bentonite or composite bentonite is completely feasible, the pellet quality is improved, and the green pellet index and the finished pellet compressive strength are improved, so that the yield of the blast furnace is increased, the coke is saved, the energy is saved, the emission is reduced, and the ring formation of the rotary kiln is reduced.

The above description is only for the purpose of illustrating the preferred embodiments of the present invention and is not to be construed as limiting the invention, and any modifications, equivalents, improvements and the like that fall within the spirit and principle of the present invention are intended to be included therein.