阅读说明：本技术 一种含镍污泥烧结预处理方法 (Sintering pretreatment method for nickel-containing sludge ) 是由 刘超 霍成立 杨文明 王荀 黄仙 王志平 庞杰 于 2021-10-20 设计创作，主要内容包括：本发明公开了一种含镍污泥烧结预处理方法,属于镍污泥预处理技术领域,包括将含镍污泥进行烘干；将烘干后的含镍污泥与烘干的含铜污泥、红土镍矿及燃料进行混合得到混合料；将混合料进行造球,得到球状混合料；将球状混合料放入烧结设备进行烧结,得到烧结块；烘干后的含镍污泥与烘干的含铜污泥、红土镍矿的质量比例为5-7份:2-4份:1-2份,且燃料质量为混合料质量的15%-18%。本发明加入烘干后的含铜污泥与红土镍矿,所得烧结块中金属铬的含量明显降低,可稳定在2.50%以下,对后续熔炼过程的不利影响显著降低。(The invention discloses a sintering pretreatment method of nickel-containing sludge, belonging to the technical field of nickel sludge pretreatment, comprising the steps of drying the nickel-containing sludge; mixing the dried nickel-containing sludge with the dried copper-containing sludge, the laterite-nickel ore and fuel to obtain a mixture; pelletizing the mixture to obtain a spherical mixture; putting the spherical mixture into sintering equipment for sintering to obtain a sintered block; the mass ratio of the dried nickel-containing sludge to the dried copper-containing sludge and the dried laterite-nickel ore is 5-7 parts to 2-4 parts to 1-2 parts, and the mass of the fuel is 15-18% of the mass of the mixture. According to the invention, the dried copper-containing sludge and the laterite-nickel ore are added, so that the content of metallic chromium in the obtained sintered block is obviously reduced and can be stabilized below 2.50%, and the adverse effect on the subsequent smelting process is obviously reduced.)

1. A sintering pretreatment method for nickel-containing sludge is characterized by comprising the following steps:

drying the nickel-containing sludge;

mixing the dried nickel-containing sludge with the dried copper-containing sludge, the laterite-nickel ore and fuel to obtain a mixture;

pelletizing the mixture to obtain a spherical mixture;

putting the spherical mixture into sintering equipment for sintering to obtain a sintered block;

wherein the mass ratio of the dried nickel-containing sludge to the dried copper-containing sludge to the laterite-nickel ore is 5-7 parts to 2-4 parts to 1-2 parts, and the mass of the fuel is 15-18% of the mass of the mixture.

2. The nickel-containing sludge sintering pretreatment method according to claim 1, wherein the moisture content of the dried nickel-containing sludge is 20% -55%.

3. The nickel-bearing sludge sintering pretreatment method of claim 1, characterized in that the SiO in the lateritic nickel ore₂The content is 20-45%.

4. The nickel-containing sludge sintering pretreatment method according to claim 1, wherein the fuel is coke powder or coal powder.

5. The nickel-containing sludge sintering pretreatment method according to claim 1, wherein the diameter of the spherical mixture is 10-20 mm.

6. The nickel-containing sludge sintering pretreatment method of claim 1, wherein the dried copper-containing sludge has an organic content of > 20%.

7. The nickel-containing sludge sintering pretreatment method according to claim 1, wherein an apparatus for pelletizing the mixture is a disk pelletizer or a drum pelletizer.

8. The nickel-containing sludge sintering pretreatment method according to claim 1, wherein the sintering equipment is a vertical sintering furnace or a horizontal sintering furnace.

Technical Field

The invention belongs to the technical field of nickel sludge pretreatment, and particularly relates to a sintering pretreatment method for nickel-containing sludge.

Background

The nickel-containing sludge is mainly derived from the wastewater treatment process in the metal surface treatment industry, and often contains various heavy metals, and has complex components and the water content of 60-70%. The hydroxides of heavy metals such as nickel, copper, chromium and the like in the nickel-containing sludge are in an unstable state, and if the hydroxides are randomly stacked, the heavy metals are likely to be dissolved out again under the rainwater leaching action, so that the soil or underground water is polluted, and the environmental ecology is damaged. Therefore, this type of sludge has been listed in the national records of hazardous waste (2021 edition), the hazardous waste category being HW17 (surface treatment waste). On the other hand, as mineral resources are gradually exhausted, the comprehensive utilization of resources and the development of circular economy become inevitable choices. The valuable metal content in the nickel-containing sludge is usually higher than the mining grade of primary mineral resources, the content of metallic nickel can reach 2.0-10.0%, the content of copper can reach 1.0-5.0%, the nickel-containing sludge is used as a high-quality nonferrous metal secondary resource, and the valuable metals in the nickel-containing sludge are enriched and recovered by using a proper process, so that the environmental hazard can be reduced, the environmental risk is reduced, the development of circular economy can be promoted, the continuous consumption of metal resources is slowed down, and the national metal resource guarantee degree is improved.

The resource utilization process of the nickel-containing sludge comprises a wet leaching process and a pyrometallurgical smelting process, and most pyrometallurgical smelting processes in the prior industry are main processesComprises a closed blast furnace smelting process and an oxygen-enriched molten pool smelting process. The nickel-containing sludge has extremely high water content and no fixed form, and needs to be pretreated before pyrometallurgical smelting, wherein the current common pretreatment mode is a drying-sintering pretreatment process. The existing water treatment process by using underground coal gasification waste heat in a high-efficiency evaporation mode is to mix dried nickel-containing sludge and fuel (usually coke powder or coal powder) for pelletizing, then feed the pellets into a sintering furnace, blow air for supporting combustion to heat the material layer for combustion, melt the low-melting-point components into a liquid phase, cool the liquid phase gradually and stick the difficult-to-melt components together to form a block material, and obtain a sintered block. The sintering process mainly has the following technical problems: the content of nickel-containing sludge organic matters produced in the surface treatment process is less than 5%, the heat value of the nickel-containing sludge organic matters is low, so that the burning speed on a sinter bed is slow, the sintering efficiency is low, the treatment capacity is small, and the fuel consumption is large; SiO exists in the nickel-containing sludge produced in the surface treatment process₂The content of the high-strength sintered brick is less than 3%, and the liquid phase generation amount is small during sintering, so that the strength of a sintered brick is low, the agglomeration rate is low, and the amount of powder is large; the dried nickel-containing sludge has poor viscosity and light specific gravity, and the specific gravity is only 1g/cm³On the left and right sides, when pelletizing, it is difficult to obtain pellets with uniform particle size, the mechanical strength of the pellets is poor due to too many small-particle pellets and fine powder, which results in poor air permeability of a material layer during sintering, slow burning speed on the material layer and uneven burning, and raw materials are mixed locally; the content of metallic chromium in the nickel-containing sludge produced in the surface treatment process is high and can reach more than 3% on average, chromium in the sinter cake can be further enriched to more than 4%, and the subsequent smelting process can be seriously influenced by the excessively high content of chromium, so that the melting point of smelting slag is increased, the fluidity is deteriorated, and the fuel consumption is increased.

Disclosure of Invention

Aiming at the problems, the invention provides a nickel-containing sludge sintering pretreatment method for solving the technical problems of low pelletizing strength, uneven granularity, slow material layer burning, low efficiency, small treatment capacity, low agglomeration rate, poor agglomeration strength, overhigh chromium content in agglomerates and the like in the conventional nickel-containing sludge sintering pretreatment process, which comprises the following steps:

drying the nickel-containing sludge;

mixing the dried nickel-containing sludge with the dried copper-containing sludge, the laterite-nickel ore and fuel to obtain a mixture;

pelletizing the mixture to obtain a spherical mixture;

putting the spherical mixture into sintering equipment for sintering to obtain a sintered block;

wherein the mass ratio of the dried nickel-containing sludge to the dried copper-containing sludge to the laterite-nickel ore is 5-7 parts to 2-4 parts to 1-2 parts, and the mass of the fuel is 15-18% of the mass of the mixture.

Preferably, the water content of the dried nickel-containing sludge is 20-55%.

Preferably, SiO in the laterite-nickel ore₂The content is 20-45%.

Preferably, the fuel is coke powder or coal powder.

Preferably, the diameter of the ball-shaped mixture is 10-20 mm.

Preferably, the dried copper-containing sludge has an organic content of > 20%.

Preferably, the equipment for pelletizing the mixture is a disc pelletizer or a roller pelletizer.

Preferably, the sintering equipment is a vertical sintering furnace or a horizontal sintering furnace.

Compared with the prior art, the invention has the beneficial effects that:

according to the invention, the copper-containing sludge and the nickel-containing sludge are mixed and sintered, so that the heat value of the mixture can be improved, the material bed combustion speed is increased, the sintering efficiency is improved, the treatment capacity is improved by 68%, and the fuel coke powder consumption is reduced by 14.3%; SiO in laterite-nickel ore₂High content, can obviously improve SiO in the sintering mixture₂The content of the nickel-containing mud increases the yield of a molten liquid phase during sintering, improves the strength of a sintered block, increases the blocking rate by 67.0%, and the laterite-nickel ore contains higher clay components, so that the pelletizing effect of the nickel-containing mud can be greatly improved, the mechanical strength of a pellet material is improved, the air permeability of a sinter bed is remarkably improved, the bed is uniformly combusted, and the phenomenon of entrainment is eliminated; the metallic chromium in the copper-containing sludge and the laterite-nickel ore is low, and the copper-containing sludge and the nickel-containing sludge are mixed and sinteredThe content of metal chromium in the obtained sintered block can be reduced to below 2.5 percent, so that the subsequent smelting process is smoother, the copper-nickel metal in each material is recovered, the waste characteristics are coupled, the treatment efficiency and the product quality are improved, the treatment cost is reduced, and the waste synergistic resource utilization is realized.

Drawings

FIG. 1 is a schematic flow chart of a synthesis method of a sintering pretreatment method for nickel-containing sludge.

Detailed Description

In order to make the objects, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are some, but not all, embodiments of the present invention. All other embodiments, which can be obtained by a person skilled in the art without any inventive step based on the embodiments of the present invention, are within the scope of the present invention.

A sintering pretreatment method for nickel-containing sludge comprises the following steps:

drying the nickel-containing sludge, wherein the water content of the dried nickel-containing sludge is 20-55%;

mixing the dried nickel-containing sludge with the dried copper-containing sludge, the laterite-nickel ore and the fuel to obtain a mixture, wherein the content of organic matters in the dried copper-containing sludge>20 percent of SiO in the laterite-nickel ore₂The content is 20% -45%, and the fuel is coke powder or coal powder;

pelletizing the mixture to obtain a spherical mixture, wherein the diameter of the spherical mixture is 10-20mm, and the equipment for pelletizing the mixture is a disc pelletizer or a roller pelletizer;

sintering the spherical mixture in a sintering device to obtain a sintered block, wherein the sintering device is a vertical sintering furnace or a horizontal sintering furnace;

wherein the mass ratio of the dried nickel-containing sludge to the dried copper-containing sludge and the laterite-nickel ore is 5-7 parts to 2-4 parts to 1-2 parts, and the mass of the fuel is 15-18% of the mass of the mixture.

Example 1

The water content of the dried nickel-containing sludge is 24 percent, the organic matter content of the dried copper-containing sludge is 33 percent, and the content of the laterite-nickel ore SiO is₂The content is 43 percent; the dried nickel-containing sludge accounts for 50 percent of the mixture, the dried copper-containing sludge accounts for 40 percent of the mixture, and the laterite-nickel ore accounts for 10 percent of the mixture. The fuel is coke powder, the fixed carbon content is 81.2 percent, and the adding weight proportion is 15.00 percent of the mass of the mixture. Preparing ball materials with the particle size of 10mm-20mm by using a disc granulator, feeding the ball materials into a horizontal sintering furnace for sintering, wherein the daily handling capacity is 126 tons, the blocking rate is 74.5 percent, and the content of metal chromium in the obtained sintered block is 2.15 percent.

Example 2

The water content of the dried nickel-containing sludge is 35 percent, the organic matter content of the dried copper-containing sludge is 31 percent, and the content of the laterite-nickel ore SiO is₂The content is 38%; the dried nickel-containing sludge accounts for 60 percent of the mixture, the dried copper-containing sludge accounts for 30 percent of the mixture, and the laterite-nickel ore accounts for 10 percent of the mixture. The fuel is coke powder, the fixed carbon content is 81.2 percent, and the adding proportion is 15.30 percent of the mass of the mixture. Preparing ball materials with the particle size of 10mm-20mm by using a disc granulator, feeding the ball materials into a horizontal sintering furnace for sintering, wherein the daily treatment capacity is 117 tons, the blocking rate is 74.2 percent, and the content of metal chromium in the obtained sintered block is 2.37 percent.

Example 3

The water content of the dried nickel-containing sludge is 41 percent, the organic matter content of the dried copper-containing sludge is 28 percent, and the content of the laterite-nickel ore SiO is₂The content was 33%. The dried nickel-containing sludge accounts for 60 percent of the mixture, the dried copper-containing sludge accounts for 25 percent of the mixture, and the laterite-nickel ore accounts for 15 percent of the mixture. The fuel is coke powder, the fixed carbon content is 81.2 percent, and the adding proportion is 15.75 percent of the mass of the mixture. Preparing ball materials with the particle size of 10mm-20mm by using a disc granulator, feeding the ball materials into a horizontal sintering furnace for sintering, wherein the daily handling capacity is 110 tons, the blocking rate is 80.2 percent, and the content of metal chromium in the obtained sintered block is 2.03 percent.

Example 4

The water content of the dried nickel-containing sludge is 48 percent, the organic matter content of the dried copper-containing sludge is 25 percent, and the content of the laterite-nickel ore SiO is₂The content was 27%. The dried nickel-containing sludge accounts for 60 percent of the mixture, the dried copper-containing sludge accounts for 20 percent of the mixture, and the laterite-nickel ore accounts for 20 percent of the mixture. The fuel being cokeThe content of fixed carbon in the powder is 81.2 percent, and the adding proportion is 16.00 percent of the mass of the mixture. Preparing ball materials with the particle size of 10mm-20mm by using a disc granulator, feeding the ball materials into a horizontal sintering furnace for sintering, wherein the daily treatment capacity is 103 tons, the blocking rate is 84.0 percent, and the content of metal chromium in the obtained sintered block is 1.93 percent.

Example 5

The water content of the dried nickel-containing sludge is 53 percent, the organic matter content of the dried copper-containing sludge is 21 percent, and the content of the laterite-nickel ore SiO is₂The content is 22%. The dried nickel-containing sludge accounts for 70 percent of the mixture, the dried copper-containing sludge accounts for 20 percent of the mixture, and the laterite-nickel ore accounts for 10 percent of the mixture. The fuel used is coke powder, the fixed carbon content is 81.2 percent, and the adding proportion is 16.25 percent of the mass of the mixture. Preparing ball materials with the particle size of 10mm-20mm by using a disc granulator, feeding the ball materials into a horizontal sintering furnace for sintering, wherein the daily handling capacity is 102 tons, the blocking rate is 71.7 percent, and the content of metal chromium in the obtained sintered block is 2.01 percent.

Comparative example 1

The water content of the dried nickel-containing sludge is 45%, and the dried copper-containing sludge and the laterite-nickel ore are not added. The fuel used is coke powder, the fixed carbon content is 81.2 percent, and the adding proportion is 17.50 percent of the mass of the mixture. Preparing ball materials with the particle size of 10mm-20mm by using a disc granulator, feeding the ball materials into a horizontal sintering furnace for sintering, wherein the daily handling capacity is 75 tons, the blocking rate is 50.3 percent, and the content of metal chromium in the obtained sintered block is 3.83 percent.

Comparative example 2

The water content of the dried nickel-containing sludge is 31 percent, and the organic matter content of the dried copper-containing sludge is 25 percent. The dried nickel-containing sludge accounts for 80% of the mixture, the dried copper-containing sludge accounts for 20%, and no laterite-nickel ore is added. The fuel used is coke powder, the fixed carbon content is 81.2 percent, and the adding proportion is 16.12 percent of the mass of the mixture. Preparing ball materials with the particle size of 10mm-20mm by using a disc granulator, feeding the ball materials into a horizontal sintering furnace for sintering, wherein the daily handling capacity is 99 tons, the blocking rate is 54.3 percent, and the content of metal chromium in the obtained sintered block is 2.98 percent.

Comparative example 3

The water content of the dried nickel-containing sludge is 42 percent, and the laterite-nickel ore SiO₂The content is 26 percent, and the mixture is driedThe content of the nickel-containing sludge is 80 percent, the content of the laterite-nickel ore is 20 percent, and the dried copper-containing sludge is not added. The fuel used is coke powder, the fixed carbon content is 81.2 percent, and the adding proportion is 17.50 percent of the mass of the mixture. Preparing ball materials with the particle size of 10mm-20mm by using a disc granulator, feeding the ball materials into a horizontal sintering furnace for sintering, wherein the daily handling capacity is 87 tons, the blocking rate is 79.6 percent, and the content of metal chromium in the obtained sintered block is 2.84 percent.

The experimental data obtained by the above examples are shown in table 1.

TABLE 1

	Example 1	Example 2	Example 3	Example 4	Example 5	Comparative example 1	Comparative example 2	Comparative example 3
									Copper-containing sludge organic matter content (%)	33	31	28	25	21	-	31	-
Content of laterite nickel ore SiO2 (%)	43	38	33	27	22	-	25	26
									Nickel-containing sludge: copper-containing sludge: mixing proportion of laterite-nickel ore	5:4:1	6:3:1	6:2.5:1.5	6:2:2	7:2:1	10:0:0	8:2:0	8:0:2
Required addition ratio of Coke powder (%)	15.00	15.30	15.75	16.00	16.25	17.50	16.12	17.50
									Daily treatment capacity (t/d)	126	117	110	103	102	75	99	87
Percentage of blocking (%)	74.5	74.2	80.2	84.0	71.7	50.3	54.3	79.6
									Metallic chromium content (%)	2.15	2.37	2.03	1.93	2.01	3.83	2.98	2.84

As can be seen from the examples and comparative examples, when the dried nickel-containing sludge was sintered alone, the required coke powder addition rate was 17.50%, the daily throughput was 75 tons, the caking rate was 50.3%, and the metallic chromium content in the sintered cake was 3.83%. With the addition of the dried copper-containing sludge, the coke powder rate required in the sintering process is obviously reducedLow amplitude of reduction can reach 14.3%. The reason is that the organic matter content in the dried copper-containing sludge is high, and the heat value of the sludge is high, so that the overall heat value of the mixed material is greatly improved, and the coke powder rate required by sintering is reduced. With the addition of the laterite-nickel ore, the agglomeration rate of the sinter cake is remarkably improved, and the amplification can reach 67%. This is because of the SiO in laterite-nickel ore₂The content is high, the liquid phase production amount in the sintering process can be greatly increased, and the agglomeration rate and the strength of the sintered agglomerates are further improved. The addition of the dried copper-containing sludge and the laterite-nickel ore can improve the burning speed on the material layer, improve the sintering efficiency and the treatment capacity, and the amplification can reach 68 percent. On the one hand, the sludge has high self heat value and is easy to burn due to the copper, and on the other hand, the mechanical strength of the ball material promoted by the clay components in the laterite-nickel ore improves the air permeability of the material layer. Due to the addition of the dried copper-containing sludge and the laterite-nickel ore, the content of metallic chromium in the obtained sintered block is obviously reduced and can be stabilized below 2.50 percent, and the adverse effect on the subsequent smelting process is obviously reduced.

The above is only a preferred embodiment of the present invention, and is not intended to limit the present invention, and various modifications and changes will occur to those skilled in the art. Any modification, equivalent replacement, or improvement made within the spirit and principle of the present invention should be included in the protection scope of the present invention.