CN-117718312-B - Harmless resource utilization method for suspension roasting sulfur-containing cyanidation tailings

Abstract

A harmless resource utilization method for suspension roasting sulfur-containing cyanidation tailings belongs to the field of safe disposal of hazardous wastes. The invention adopts a two-stage roasting mode, and obtains the sintered tile which accords with GB/T21149-2019 sintered tile by adjusting the reaction conditions such as roasting atmosphere, temperature, heat preservation time and the like in the suspension roasting process. The method is used for removing the highly toxic cyanide and simultaneously realizing the solidification of sulfide and heavy metal, wherein the cyanide removal rate and the heavy metal solidification rate are both over 99 percent, and the sulfur solidification rate is more than 90 percent. The method can realize the purposes of harmless treatment and recycling of cyanide tailings in one step, and has the advantages of environmental protection, economy and social benefits.

Inventors

• ZHANG YUHAI
• ZHANG FAN
• ZHANG JIANTING
• Dong Mangui

Assignees

• 上海逢石科技有限公司

Dates

Publication Date

20260508

Application Date

20231212

Claims (3)

1. 1. A harmless resource utilization method for suspension roasting sulfur-containing cyanidation tailings is characterized by comprising the following steps: Step 1, uniformly mixing sulfur-containing cyanidation tailings with lycra, performing spray drying granulation, powder preparation and compression molding to obtain a sintered blank, and feeding the sintered blank into a suspension roasting oxidation furnace system, wherein the addition amount of the lycra is less than or equal to 15% of the mass of the sulfur-containing cyanidation tailings; Step 2, setting the atmosphere, the roasting temperature, the heating rate and the heat preservation time of the suspension roasting oxidation system, and then sintering the sintered blank in a two-stage roasting mode in a suspension roasting oxidation furnace; step 3, pressing and forming the blank after suspension roasting to obtain a sintered tile; In the step 2, in the roasting process, the first-stage roasting atmosphere is the mixture of water vapor and air, the concentration ratio of the water vapor is 5-35%, the roasting temperature is 280-450 ℃, the heating rate is 3-15 ℃ per minute, the heat preservation time is 0-3 min, the second-stage roasting atmosphere is air, the roasting temperature is 1050-1180 ℃, the heating rate is 8-15 ℃ per minute, the roasting atmosphere is air, and the heat preservation time is 1-60 min; The sulfur solidification rate of the cyanide tailings after roasting is more than 90%, the cyanide removal rate is more than 99%, and the heavy metal solidification rate of the cyanide tailings after roasting is more than 99%; The water absorption rate of the sintered tile is 2-5%, and the flexural strength is 28-58 MPa; in the step 1, the sulfur-containing cyanide tailings comprise one or more of gold concentrate cyanide tailings generated in gold smelting production, pretreated cyanide tailings, full-mud cyanide tailings and high-silicon tailings after gold concentrate cyanide tailings flotation, wherein the main elements comprise Si, S, fe, pb, zn, cu, K, na, ca, al, mg, mn, ti, as, cd, ni, C and N; cyanide-containing materials in the sulfur cyanide-containing tailings include free cyanide, thiocyanate, iron cyanide complex, copper cyanide complex, zinc cyanide complex and lead cyanide complex; in the step 1, the sulfur content in the sulfur-containing cyanidation tailings accounts for 0.1-25% of the mass of the cyanidation tailings, the total cyanide content is 80-5000 mg/kg, and the total metal content is 5-30 g/kg; the water content of the sulfur-containing cyanidation tailings is less than or equal to 17 percent, the grain diameter is less than or equal to 250 mu m.
2. 2. The harmless recycling method for the suspension roasting sulfur-containing cyanidation tailings, which is disclosed in claim 1, is characterized in that in the step 3, the pressure is 3-18 mpa in the compression molding process.
3. 3. The harmless recycling method for the suspended roasting sulfur-containing cyanide tailings, which is characterized in that in the suspended roasting process of the cyanide tailings, degradation products of cyanide comprise NO x 、CO x and H 2 , and the total cyanide content after roasting is less than or equal to 0.5 mg/kg.

Description

Harmless resource utilization method for suspension roasting sulfur-containing cyanidation tailings Technical Field The invention belongs to the field of safe disposal of hazardous waste, and particularly relates to a harmless resource utilization method of suspension roasting sulfur-containing cyanidation tailings. Background The cyanide slag is solid waste after gold extraction, and the yield of the cyanide slag is 100% because the grade of gold is only g/t grade. Cyanide slag contains toxic and harmful substances including cyanide such as cyanide, thiocyanate, copper cyanide complex, iron cyanide complex, zinc cyanide complex and heavy metal elements, and is therefore classified as dangerous waste in the year of 2016, 8 and 1. Meanwhile, under the pressure of continuous enhancement of global environmental awareness and resource shortage, research on recycling of cyanide slag is an urgent need for sustainable development. From the existing literature, the present secondary recycling utilization of cyanide tailings mainly focuses on secondary extraction of gold and silver in the tailings, flotation recovery of sulfide, degradation of cyanide and the like, but secondary tailings and pollution are generated generally, and direct harmless resource disposal of the cyanide tailings cannot be realized. The cyanated slag sintered tile is a potential resource utilization way. Cyanide in the cyanide slag can be decomposed at high temperature during the roasting process, thereby reducing environmental risks. In addition, in the preparation process of the sintered tile, the metal elements in the cyanation slag can be solidified in the tile body, so that the recycling of metal resources is realized. However, this method still needs to overcome technical difficulties in tile strength, cyanide and sulfide emissions, and feasibility validation in industrial applications. The patent CN112608133A provides a harmless resource utilization method of cyanidation gold extraction tailings, which comprises the steps of mixing gold tailing slag, lycra, refractory clay, calcined talcum, calcite, dolomite, flint clay, alumina, diopside and potash feldspar according to a proportion to form a batch, adding the batch, sodium tripolyphosphate with the mass of 0.25-0.35% and water with the mass of 0.8-1 times of the batch into a ball mill, grinding until the 250 mesh residue of slurry is within 0.5%, spray drying, granulating, pulverizing, pressing and forming to obtain a green brick, and firing the green brick for 90-105min at 1100-1120 ℃. The method does not consider secondary pollution caused by SO 2 in the roasting process of the sulfur-containing cyanidation tailings. Patent CN116371890A provides a recycling and harmless treatment method of gold cyanide tailings, which comprises the steps of feeding the dewatered cyanide tailings into a suspension furnace for preheating, dewatering and oxidizing roasting to obtain decyanated tailings, cooling the decyanated tailings, and smelting the decyanated tailings into water slag and pig iron in an electric furnace. The method only realizes the removal of cyanide and the pretreatment of cyanide slag, needs to bake or smelt the product for the second time, has high cost and larger tailings amount, and does not realize the purpose of recycling the cyanide tailings. Disclosure of Invention The invention aims to solve the problems of secondary pollution and insufficient recycling in the treatment process of cyanide tailings, and provides a harmless recycling method for suspension roasting sulfur-containing cyanide tailings. The cyanide is degraded by two-stage roasting, the generation of SO 2 is inhibited, and meanwhile, the qualified sintered tile conforming to GB/T21149-2019 sintered tile is prepared, SO that the harmless recycling of cyanide tailings is realized. In order to achieve the above purpose, the present invention adopts the following technical scheme: a harmless resource utilization method for suspension roasting sulfur-containing cyanidation tailings comprises the following steps: 1. Uniformly mixing the sulfur-containing cyanidation tailings with the lycra, performing spray drying granulation, powder preparation and compression molding to obtain a sintered blank, and feeding the sintered blank into a suspension roasting oxidation furnace system, wherein the addition amount of the lycra is less than or equal to 15% of the mass of the sulfur-containing cyanidation tailings. 2. Setting the atmosphere, the roasting temperature, the heating rate and the heat preservation time of a suspension roasting oxidation system, and then sintering the sintered blank in a suspension roasting oxidation furnace in a two-stage roasting mode, wherein the system atmosphere is one or mixed gas of water vapor and air, the roasting temperature is 280-1180 ℃, the heating rate is 3-15 ℃ per minute, and the heat preservation time is 0-60min. 3. And (3) pressing and forming the blank after suspension roasting t