阅读说明：本技术 一种用炼锡烟化炉处理含砷石膏渣的方法 (Method for treating arsenic-containing gypsum slag by using tin-smelting fuming furnace ) 是由 陈云 袁海滨 徐万立 刘伟雄 梁军 张志胤 李乔平 代金德 刘庆东 白家福 张瑜 于 2021-09-26 设计创作，主要内容包括：一种用炼锡烟化炉处理含砷石膏渣的方法,将锡中矿按10t/h～20t/h的加料速度连续加入炼锡烟化炉内,在1100℃～1150℃温度下进行熔炼；将含砷石膏渣与黄铁矿的混合物连续加入炼锡烟化炉内,升温至1200℃～1300℃,进行烟化挥发反应；含砷石膏渣中的CaSO-(4)·2H-(2)O在弱还原气氛下分解,产出SO-(2)气体和CaO,SO-(2)气体参与锡的硫化挥发反应；CaO参与造渣；Ca-(3)(AsO-(4))-(2)不参加反应,游离砷被氧化成为As-(2)O-(3)进入烟气；将熔渣水淬得到水淬渣；将含As-(2)O-(3)的烟气冷却后收集于烟尘中,焙烧烟尘收集得到As-(2)O-(3)。本发明有效实现了含砷石膏渣的资源化综合回收利用,方法简单,安全环保。(A method for treating arsenic-containing gypsum slag by using a tin-smelting fuming furnace comprises the steps of continuously adding tin middlings into the tin-smelting fuming furnace at a feeding speed of 10 t/h-20 t/h, and smelting at the temperature of 1100-1150 ℃; continuously adding the mixture of the arsenic-containing gypsum slag and the pyrite into a tin-smelting fuming furnace, heating to 1200-1300 ℃, and carrying out fuming volatilization reaction; CaSO in arsenic-containing gypsum slag 4 ·2H 2 O is decomposed in weak reducing atmosphere to produce SO 2 Gas and CaO, SO 2 The gas participates in the sulfuration volatilization reaction of tin; CaO participates in slagging; ca 3 (AsO 4 ) 2 Does not participate in the reaction, and the free arsenic is oxidized into As 2 O 3 Entering flue gas; water quenching the molten slag to obtain water-quenched slag; will contain As 2 O 3 Cooling the flue gas, collecting the cooled flue gas in smoke dust, roasting the smoke dust, and collecting to obtain As 2 O 3 . The method effectively realizes the comprehensive recycling of the arsenic-containing gypsum slag, and is simple, safe and environment-friendly.)

1. A method for treating arsenic-containing gypsum slag by using a tin-smelting fuming furnace is characterized by comprising the following steps:

s1: mixing the arsenic-containing gypsum slag and pyrite according to the proportion of 1: 1-5, uniformly mixing for later use;

s2: continuously adding tin middling into a tin smelting fuming furnace at a feeding speed of 10 t/h-20 t/h, and smelting at the temperature of 1100-1150 ℃;

s3: continuously adding the mixture of the arsenic-containing gypsum slag and the pyrite into a tin-smelting fuming furnace, heating to 1200-1300 ℃, and carrying out fuming volatilization reaction; CaSO in arsenic-containing gypsum slag₄·2H₂O is decomposed in weak reducing atmosphere to produce SO₂Gas and CaO, SO₂The gas participates in the sulfuration volatilization reaction of tin; CaO participates in slagging; ca in arsenic-containing gypsum slag₃(AsO₄)₂Does not participate in the reaction, and the free arsenic is oxidized into As₂O₃Entering flue gas;

s4: discharging slag from a slag hole of the tin-smelting fuming furnace, and performing water quenching on the slag to obtain water-quenched slag;

s5: will contain As₂O₃Cooling the flue gas, collecting the cooled flue gas in smoke dust, roasting the smoke dust, and collecting to obtain As₂O₃。

2. The method for treating arsenic-containing gypsum slag by using the tin-smelting fuming furnace as claimed in claim 1, wherein the arsenic-containing gypsum slag contains 50-95 wt% of calcium sulfate, 0.1-10 wt% of arsenic and 5-40 wt% of water.

3. The method for treating arsenic-containing gypsum slag in a tin-making fuming furnace as claimed in claim 1, wherein the amount of the arsenic-containing gypsum slag added is determined according to the slag type, and the silicate degree of the tin-making fuming slag is maintained at 0.8-1.2.

Technical Field

The invention relates to the technical field of non-ferrous metal smelting waste residue treatment methods, in particular to a treatment method of arsenic-containing gypsum residue.

Background

The arsenic-containing gypsum slag, also called arsenic-calcium slag, is mainly derived from products produced in the process of desulfurization of smelting flue gas and treatment of arsenic-containing waste acid by using lime and iron salt method, and mainly comprises calcium sulfate (CaSO)₄·2H₂O), and heavy metal elements such As As and Pb, wherein As is mainly calcium arsenate Ca₃(AsO₄)₂And free arsenic exists, which belongs to dangerous solid waste, and can cause secondary pollution and resource waste to the environment if the dangerous solid waste cannot be effectively treated. The treatment and disposal of arsenic-containing gypsum slag (arsenic-calcium slag) has become a problem of high social concern.

At present, the main domestic methods for treating arsenic-containing gypsum slag (arsenic-calcium slag) comprise the following steps: stockpiling, cement curing, medicament curing, high-temperature reduction decomposition and the like. The stockpiling is the most common method for most enterprises at present, but the stockpiling has extremely high requirements on stockpiled slag yards and has quite large subsequent maintenance difficulty; the cement solidification can reduce the toxicity leaching of the waste residues to the range meeting the national toxicity leaching requirement, but the volume-increasing ratio is large, and the treated residues can not realize resource utilization; the adaptability of the agent curing is poor at present, experimental work is only carried out in a laboratory aiming at partial raw materials, and industrial application cannot be realized at present; the high-temperature reduction decomposition method has poor practical operability due to the fact that calcium arsenate is relatively stable. Therefore, the development of a new process for treating arsenic-containing gypsum slag (arsenic-calcium slag) which is safe, environment-friendly, economical and practical is urgently needed.

Disclosure of Invention

The invention aims to solve the problems in the prior art and provides a safe, environment-friendly, economical and practical method for treating arsenic-containing gypsum slag by using a tin-smelting fuming furnace.

The technical scheme adopted by the invention is as follows:

a method for treating arsenic-containing gypsum slag by using a tin-smelting fuming furnace comprises the following steps:

s1: mixing the arsenic-containing gypsum slag and pyrite according to the proportion of 1: 1-5, uniformly mixing for later use;

s2: continuously adding tin middling into a tin smelting fuming furnace at a feeding speed of 10 t/h-20 t/h, and smelting at the temperature of 1100-1150 ℃;

s3: continuously adding the mixture of the arsenic-containing gypsum slag and the pyrite into a tin-smelting fuming furnace, heating to 1200-1300 ℃, and carrying out fuming volatilization reaction; CaSO in arsenic-containing gypsum slag₄·2H₂O is decomposed in weak reducing atmosphere to produce SO₂Gas and CaO, SO₂The gas participates in the sulfuration volatilization reaction of tin;CaO participates in slagging; ca in arsenic-containing gypsum slag₃(AsO₄)₂Does not participate in the reaction, and the free arsenic is oxidized into As₂O₃Entering flue gas;

s4: discharging slag from a slag hole of the tin-smelting fuming furnace, and performing water quenching on the slag to obtain water-quenched slag;

s5: will contain As₂O₃Cooling the flue gas, collecting the cooled flue gas in smoke dust, roasting the smoke dust, and collecting to obtain As₂O₃。

The arsenic-containing gypsum residue contains 50-95 wt% of calcium sulfate, 0.1-10 wt% of arsenic and 5-40 wt% of water.

The amount of the arsenic-containing gypsum slag added is determined according to the slag type, and the silicate degree of the tin-making fuming slag is maintained to be 0.8-1.2.

In the invention, arsenic-containing gypsum slag is used as a vulcanizing agent and added into a fuming furnace, and CaSO in the arsenic-containing gypsum slag₄·2H₂O is decomposed in the weak reducing atmosphere in the furnace to produce SO₂Gas and CaO, SO₂The gas directly participates in the sulfuration volatilization reaction of the tin, and the conversion and utilization of the sulfur are realized. And (3) CaO participates in slagging, water quenching is carried out after slag is discharged to obtain water-quenched slag, and the water-quenched slag can be used for manufacturing novel building materials such as cement, baking-free bricks and the like. Calcium arsenate Ca in arsenic-containing gypsum slag₃(AsO₄)₂Is very stable and does not participate in the reaction, free arsenic is oxidized into arsenic trioxide to enter the flue gas, and the arsenic trioxide is collected in the smoke dust after being cooled. The specific reaction formula is as follows:

the main component calcium sulfate of the arsenic-containing gypsum slag is reduced and decomposed into CaO and SO₂：

CaSO₄+CO＝CaO+SO₂+CO₂

Decomposition reaction and oxidation reaction of pyrite

FeS_2(S)＝(FeS)+1/2S₂

(FeS)+3/2O₂＝(FeO)+SO₂

Produced SO₂The gas participates in the sulfuration volatilization reaction of tin

Sn+SO₂+2CO＝SnS+2CO₂

SnO+SO₂+3CO＝SnS+3CO₂

SnO₂+SO₂+4CO＝SnS+4CO₂

Produced SO₂The gas participates in the sulfuration volatilization reaction of lead

Pb+SO₂+2CO＝PbS+2CO₂

PbO+SO₂+3CO＝PbS+3CO₂

Oxidation and reduction reactions occur in the pyrometallurgical process, and slagging reactions also occur:

xCaO+ySiO₂＝xCaO·ySiO₂

xFeO+ySiO₂＝xFeO·ySiO₂

CaO+Fe₂O₃＝CaO·Fe₂O₃

the main components of the slag are FeO, CaO and SiO₂All exist in the form of composite oxides, and are high-quality raw materials for producing cement.

The free arsenic reacts with oxygen at high temperature and volatilizes into flue gas, and is collected in the form of smoke dust after being cooled in a dust collector to form high-arsenic flue dust:

2As+1.5O₂＝As₂O₃

after the high-arsenic smoke dust is roasted, arsenic can be separated from fuming dust produced by the fuming furnace, and the separated arsenic is As₂O₃The form is collected and sold, and the roasted smoke dust can be returned to a tin smelting system for smelting.

The invention has the following beneficial effects:

(1) the existing equipment of a smelting plant can be fully utilized, and the investment is reduced;

(2) the arsenic-containing gypsum slag is used as a vulcanizing agent of the fuming furnace, can partially replace pyrite, and reduces the production cost;

(3) SO produced by gypsum residue decomposition₂The gas participates in the sulfuration volatilization reaction, which is beneficial to the recycling of sulfur;

(4) CaO produced by gypsum slag decomposition participates in slagging, and the slag can be used for manufacturing novel building materials such as cement, baking-free bricks and the like, and can also be used as general II-type industrial solid waste for stockpiling;

(5) the free arsenic in the gypsum slag is volatilized at high temperature to enter smoke dust, and is roasted to be As₂O₃Collecting;

(6) the sulfur-containing flue gas produced by the tin fuming furnace can be used for preparing acid by using an existing acid preparation system of a smelting plant.

The invention effectively realizes the comprehensive recycling of the arsenic-containing gypsum slag, promotes the arsenic-containing gypsum slag to be converted from hazardous waste to general II-type industrial solid waste, and simultaneously obtains a water-quenched slag product with certain economic value. The method is simple, easy to operate, safe and environment-friendly, provides an effective way for treating the arsenic-containing gypsum slag, and has wide application prospect.

Drawings

FIG. 1 is a process flow diagram of the method of the present invention.

Detailed Description

A method for treating arsenic-containing gypsum slag by using a tin-smelting fuming furnace has a process flow as shown in figure 1, and comprises the following specific steps:

s1: mixing the arsenic-containing gypsum slag and pyrite according to the proportion of 1: 1-5, and taking the mixture as a vulcanizing agent for standby.

S2: the tin middling is continuously added into a tin smelting fuming furnace according to the feeding speed of 10 t/h-20 t/h, and smelting is carried out at the temperature of 1100-1150 ℃. The tin middlings refer to tin ores containing 1-10% of tin. The tin in the tin middling is volatilized into smoke dust through fuming, and the grade of the tin is improved.

S3: in the process of smelting tin middling, continuously adding a mixture of arsenic-containing gypsum slag and pyrite into a tin-smelting fuming furnace, heating to 1200-1300 ℃, and carrying out fuming volatilization reaction; CaSO in arsenic-containing gypsum slag₄·2H₂O is decomposed in weak reducing atmosphere to produce SO₂Gas and CaO, SO₂The gas participates in the sulfuration volatilization reaction of tin; CaO participates in slagging; ca in arsenic-containing gypsum slag₃(AsO₄)₂Does not participate in the reaction, and the free arsenic is oxidized into As₂O₃Entering flue gas;

the main component of the arsenic-containing gypsum slag is sulfurCalcium carbonate (CaSO)₄·2H₂O), and heavy metal elements such As As and Pb, wherein As is mainly calcium arsenate Ca₃(AsO₄)₂And free arsenic form. The arsenic-containing gypsum slag contains 50-95 wt% of calcium sulfate, 0.1-10 wt% of arsenic and 5-40 wt% of water. The adding amount of the arsenic-containing gypsum slag is determined according to the slag type, and the silicate degree of the tin-making fuming slag is maintained to be 0.8-1.2. At this silicate, the slag has a low viscosity and good fluidity, and SnS is easily volatilized from the slag.

S4: discharging slag from a slag hole of the tin-smelting fuming furnace, and performing water quenching on the slag to obtain water-quenched slag;

s5: will contain As₂O₃Cooling the flue gas, collecting the cooled flue gas in smoke dust, roasting the smoke dust, and collecting to obtain As₂O₃。

The invention relates to a tin smelting fuming furnace, which belongs to the equipment in the prior art.

Example 1

Adding arsenic-containing gypsum slag (the components of As 5-10%, Ca 20-30% and S10-15%) into a tin-smelting fuming furnace according to the ratio of sulfur in the slag to tin in materials in the fuming furnace being 1:4, carrying out vulcanization volatilization of tin, and obtaining slag-throwing components: 0.213% of Sn, 5.41% of Ca, 0.028% of As, 32.82% of Fe and 9.89% of Si, and the produced smoke comprises the following components: sn 51.16%, As 2.86%, and flue gas containing 10000-11000 mg/m of sulfur³And sending the sulfuric acid to an acid preparation system to produce sulfuric acid. The slag is used for manufacturing cement, the smoke dust directly returns to a tin smelting system, arsenic is removed in the form of arsenic trioxide after roasting, and the roasted smoke dust is smelted to produce a tin product. The sulfur in the arsenic-containing gypsum slag participates in the volatilization reaction of tin, and the arsenic volatilizes into the tin-containing smoke dust, so that the arsenic gypsum slag is recycled.

Example 2

Adding arsenic-containing gypsum slag (the components of As 5-10%, Ca 20-25% and S10-15%) into a tin-smelting fuming furnace according to the ratio of sulfur in the slag to tin in materials in the fuming furnace of 1:3.5, and carrying out vulcanization volatilization of tin, wherein the produced slag-throwing components are As follows: 0.222% of Sn, 6.4% of Ca, 0.024% of As, 37.83% of Fe, 10.89% of Si, and the produced smoke comprises the following components: 51.22% of Sn, 2.67% of As, 10000-11000 mg/m of sulfur contained in flue gas³And sending the sulfuric acid to an acid preparation system to produce sulfuric acid. The slag is used for manufacturing cement, the smoke dust directly returns to a tin smelting system, arsenic is removed in the form of arsenic trioxide after roasting, and the roasted smoke dust is smelted to produce a tin product. The sulfur in the arsenic-containing gypsum slag participates in the volatilization reaction of tin, and the arsenic volatilizes into the tin-containing smoke dust, so that the arsenic gypsum slag is recycled.

Example 3

Mixing arsenic-containing gypsum slag (the components of As 5-10%, Ca 20-25% and S10-15%) with pyrite, adding the mixture into a tin-smelting fuming furnace according to the ratio of sulfur to tin in the fuming furnace being 1:4, carrying out vulcanization volatilization on tin, and obtaining the slag-throwing components: 0.24% of Sn, 5.16% of Ca, 0.038% of As, 35.53% of Fe, 9.51% of Si, and the produced smoke comprises the following components: 50.21% of Sn, 1.84% of As, 10000-11000 mg/m of sulfur contained in flue gas³And sending the sulfuric acid to an acid preparation system to produce sulfuric acid. The slag is used for manufacturing cement, the smoke dust directly returns to a tin smelting system, arsenic is removed in the form of arsenic trioxide after roasting, and the roasted smoke dust is smelted to produce a tin product. The sulfur in the arsenic-containing gypsum slag participates in the volatilization reaction of tin, and arsenic volatilizes into tin-containing smoke dust, so that the arsenic-containing gypsum slag is recycled.

Effect analysis

The invention mixes tin middling, pyrite and arsenic-containing gypsum slag according to a certain proportion, continuously adds the mixture into a tin-smelting fuming furnace for smelting, and controls the atmosphere in the furnace and the temperature of a molten pool by adjusting air quantity, oxygen quantity, coal feeding quantity of a spray gun pulverized coal and the like. Smelting at 1100-1150 deg.c; and continuously adding the mixture of the arsenic-containing gypsum slag and the pyrite into a fuming furnace, heating to 1200-1300 ℃, and completing the decomposition of calcium sulfate in the arsenic-containing gypsum slag and iron sulfide in the pyrite. Production of CO and SO₂Gas, tin oxide produced by melting tin middlings, CO and SO₂Performing interactive reaction, volatilizing for 1.5-2 h, discharging and throwing slag from a slag hole, recovering waste heat of high-temperature flue gas, collecting dust and other SO₂Mixing the flue gas, sending the mixture to acid making, circularly smelting, and discharging and throwing slag every 3-4 hours. Compared with the traditional treatment process, the method has the advantages of good environmental protection effect, high recovery efficiency, reduced limestone consumption in the smelting process, contribution to reduction of production cost and recoveryThe equipment adopts the original equipment to treat, does not need additional investment, efficiently treats waste residues, effectively prevents environmental pollution, saves energy, protects environment, and obtains benefits from the process of treating harmful substances.

The method has low consumption and high efficiency, realizes the recovery of arsenic, solves the problem of stockpiling of arsenic-containing gypsum slag, reduces the dosage of limestone in the smelting process, and provides a green, environment-friendly, economic and high-efficiency treatment method for harmless treatment of the arsenic-containing gypsum slag.

All percentages stated in the present invention are percentages by mass, unless otherwise stated.

Finally, the above embodiments and the accompanying drawings are only intended to illustrate the technical solution of the present invention and not to limit, and although the present invention has been described in detail by the above embodiments, it will be understood by those skilled in the art that various changes in form and detail may be made therein without departing from the scope of the present invention as defined by the claims.