CN113185265B

CN113185265B - Cyanide sludge sintering cyanogen removal process, cyanide-free brick, cyanide sludge sintering cyanogen removal system and application

Info

Publication number: CN113185265B
Application number: CN202110741209.3A
Authority: CN
Inventors: 杨航; 李勇; 李伟光; 赵庆朝; 朱阳戈
Original assignee: Beijing General Research Institute of Mining and Metallurgy
Current assignee: Beijing General Research Institute of Mining and Metallurgy
Priority date: 2021-07-01
Filing date: 2021-07-01
Publication date: 2021-11-05
Anticipated expiration: 2041-07-01
Also published as: CN113185265A

Abstract

The invention provides a cyanide sludge sintering cyanogen removal process, a cyanide-free brick, a cyanide sludge sintering cyanogen removal system and application, and particularly relates to the technical field of cyanide sludge disposal and utilization. The cyanide sludge sintering and cyanogen removing process is to mix and form cyanide sludge and combustible materials and then sinter and remove cyanogen to obtain the cyanide-free brick. The cyanide sludge and the combustible are preferably mixed according to the mass ratio of 70-95: 5-30, the oxygen concentration during sintering and cyanogen removal is more than 10%, the temperature for sintering and cyanogen removal is 950-1100 ℃, the pressure is-100-0 Pa, and the time is 24-36 h. According to the cyanide sludge sintering cyanide removal process provided by the invention, the cyanide removal rate reaches more than 99.9%, the waste heat of a sintering kiln is secondarily utilized in the process, and the comprehensive energy consumption and the disposal cost are low; the mechanical automation degree is high in the process, the final product is harmless to the environment, and the cyanogen-free brick with economic value is obtained and is suitable for large-scale use in the field of cyaniding tailing treatment in industries such as gold and the like.

Description

Cyanide sludge sintering cyanogen removal process, cyanide-free brick, cyanide sludge sintering cyanogen removal system and application

Technical Field

The invention relates to the technical field of cyanide sludge treatment and utilization, in particular to a cyanide sludge sintering decyanation process, a cyanide-free brick, a cyanide sludge sintering decyanation system and application.

Background

Most finished gold production enterprises adopt cyanidation gold extraction processes, so that a large amount of cyanogen slag is generated every year, and the cyanidation tailing yield of the gold industry in China is about 1 hundred million tons per year. The existing cyanogen slag decyanation treatment method comprises an ozone oxidation method, a solid-liquid separation washing method, an inconel method, a natural degradation method, a high-temperature hydrolysis method and the like, and the methods mainly have the following defects:

the process flow is complex;

the investment and operation cost is high;

the requirement of manual operation is strict;

cyanide removal is not complete.

In view of the above, the present invention is particularly proposed.

Disclosure of Invention

One of the purposes of the invention is to provide a cyanide sludge sintering cyanide removal process to relieve the technical problems of complex process flow, high investment and operation cost, strict requirement on manual operation and incomplete cyanide removal in the prior art.

The invention also aims to provide the cyanide-free brick which has the characteristics of high compressive strength, good weather resistance, water resistance, fire resistance and heat preservation.

The invention also aims to provide a cyanide sludge sintering cyanide removal system, which has continuous treatment process and can obtain cyanide-free brick products without cyanide escaping.

The fourth purpose of the invention is to provide the application of the cyanide sludge sintering cyanide removal process and system, so as to solve the problem of treatment of cyanide tailings in the gold industry at present.

In order to solve the technical problems, the invention adopts the following technical scheme:

the invention provides a cyanide sludge sintering and cyanogen removing process, which comprises the steps of mixing and molding cyanide sludge and combustible materials, sintering and removing cyanogen to obtain a cyanide-free brick.

Further, the oxygen concentration is more than 10% during the sintering decyanation;

preferably, the oxygen concentration is greater than 20%.

Further, the temperature for removing cyanogen by sintering is 950-1100 ℃;

preferably, the pressure for removing cyanogen by sintering is-100-0 Pa;

preferably, the sintering time for removing cyanogen is 24-36 h.

Further, the water content of the cyanided sludge is 15-50%, and the cyanide content is 5-60 mg/kg;

preferably, the cyanided sludge and combustible are uniformly mixed and formed into a wet blank and then sintered;

preferably, the combustible comprises at least one of coal gangue, coal dust, gasified slag or slag;

preferably, the forming manner includes compression forming or extrusion forming.

Further, the mass ratio of the cyanided sludge to the combustible in the wet blank is 70-95: 5-30;

preferably, the molding pressure is 1-4 MPa.

Further, drying and dehydrating the wet blank;

preferably, the temperature of drying and dehydrating is 120-400 ℃;

preferably, the pressure of drying and dewatering is-90-0 Pa;

preferably, drying and dehydrating to obtain a pre-sintered blank, wherein the water content of the pre-sintered blank is less than or equal to 6%.

The invention provides a cyanide-free brick, which is prepared by the cyanide sludge sintering cyanide removal process provided by the first aspect.

The third aspect of the invention provides a cyanide sludge sintering decyanation system, which comprises a mixing and forming device, a closed drying kiln and a closed sintering kiln which are sequentially connected;

preferably, the device also comprises a tail gas collecting device;

preferably, the mixed forming device, the closed drying kiln and the closed sintering kiln are communicated with a tail gas collecting device;

preferably, the tail gas collecting device comprises an alkali liquor absorption tank;

preferably, the lye of the lye absorption tank comprises a sodium hydroxide solution;

preferably, the concentration of the sodium hydroxide solution is 5-10 g/L;

preferably, the closed sintering kiln is communicated with the closed drying kiln and is used for returning waste heat discharged by the closed sintering kiln to the closed drying kiln.

Further, the alkali liquor absorption tank is connected with the mixing and forming device so as to convey the alkali liquor in the alkali liquor absorption tank to the mixing and forming device.

Furthermore, the tail gas which is not absorbed by the alkali liquor absorption tank enters the atmosphere after dust removal, desulfurization and denitrification.

The fourth aspect of the invention provides the application of the cyanide sludge sintering cyanide removal process of the first aspect or the cyanide sludge sintering cyanide removal system of the third aspect in cyanide sludge treatment.

The cyanide sludge sintering decyanation process provided by the invention mixes and shapes cyanide sludge and combustible, and the combustible forms a gas channel and a decyanation site in the cyanide sludge after being combusted, so that cyanide in the cyanide sludge reacts with oxygen, and the cyanide is converted into harmless nitrogen oxide to achieve the purpose of decyanation. The sintering process directly uses oxygen in the air, does not need to use a cyanide breaking reagent with high cost, has the cyanide removal rate of over 99.9 percent, low comprehensive energy consumption and disposal cost, and has no harm to the environment of the final product.

The cyanide-free brick provided by the invention is obtained by sintering through a sintering process, has high compressive strength, good weather resistance and durability, and has the characteristics of water resistance, fire resistance, stability and heat preservation.

The cyanide sludge sintering and cyanogen removing system provided by the invention has low comprehensive energy consumption and disposal cost. The tail gas collecting device is arranged in the system, so that the escape of cyanide is avoided in the process, and the safety of the whole system is guaranteed.

The application of the cyanide sludge sintering and cyanogen removal process or system provided by the invention in treatment of cyanide sludge solves or partially solves the problem of treatment of cyanide pollutants in the gold industry, reduces the pollution of cyanide to the environment, can convert cyanide sludge into products, and has certain environmental and economic benefits.

Drawings

In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the embodiments or the prior art will be briefly described below, and it is obvious that the drawings in the following description are some embodiments of the present invention, and other drawings can be obtained by those skilled in the art without creative efforts.

Figure 1 is a process scheme for example 1.

Detailed Description

In order to make the objects, technical solutions and advantages 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 embodiments of the present invention. The components of embodiments of the present invention may be arranged and designed in a wide variety of different configurations.

More than 85% of finished gold production enterprises in China adopt cyanidation gold extraction technology, and the amount of cyanidation tailings is about 1 hundred million tons every year. The problem of cyanidation tailing disposal is a difficult problem which puzzles gold production enterprises for a long time. In 2016, 8 months and 1 day, the new national records of dangerous wastes determine cyanided tailings generated in the gold dressing process by using cyanides as dangerous wastes.

Technically, the existing cyanogen removal from cyanogen slag comprises an ozone oxidation method, a solid-liquid separation and washing method, an indigenous method, a natural degradation method, a high-temperature hydrolysis method and the like. When the cyanide tailings are treated by chemical methods such as the traditional OOT two-stage method (ozone oxidation method), the causal method (sulfur dioxide-air method) and the like, the problems of complex process flow, high investment and operation cost, strict requirement on manual operation, incomplete cyanide removal and the like exist. In some researches, a washing filter press is adopted, and the filter cake is washed and filtered on line by 0.7 time of water, so that the water content of the filter cake is 11%, and the total cyanogen content in the toxic leaching of the tailings is obviously reduced. However, cyanide is a highly toxic substance, and this operation mode is concerned about the thoroughness of the harmless disposal of cyanide. In view of the above, the invention provides a method for realizing thorough harmless treatment of cyanidation tailings, and simultaneously converts the cyanidation tailings into products, thereby having great environmental and economic benefits.

According to the cyanide sludge sintering cyanogen removal process provided by the first aspect of the invention, cyanide sludge and combustible are mixed and formed and then sintered to remove cyanogen, and a cyanide-free brick is obtained.

The cyanide sludge sintering decyanation process provided by the invention mixes and shapes cyanide sludge and combustible, and the combustible forms a gas channel and a decyanation site in the cyanide sludge after being combusted, so that cyanide in the cyanide sludge reacts with oxygen, and the cyanide is converted into harmless nitrogen oxide to achieve the purpose of decyanation. The sintering process directly uses oxygen in the air, does not need to use a cyanide breaking reagent with high cost, has the cyanide removal rate of over 99.9 percent, low comprehensive energy consumption and treatment cost, has no harm to the environment of a final product, and relieves the technical problems of complex process flow, high investment and operation cost, strict requirement on manual operation and incomplete cyanide removal in the prior art.

Further, the oxygen concentration during sintering cyanogen removal is more than 10%.

During sintering, cyanide and oxygen in the cyanide sludge react as follows:

2CN^-+O₂=2CNO^-

reaction formula (1)

CNO^-+2H₂O=2HCO₃ ^-+NH₃

Reaction type (2)

The oxygen concentration is important for decomposing cyanide, and when the oxygen concentration is more than 10%, the oxygen enters the formed blank body through a channel formed by combustion of combustible materials and reacts with the cyanide. The higher the oxygen concentration, the more thorough the decomposition of cyanide and the lower the cyanogen content in the non-cyanide bricks obtained by sintering.

In some embodiments of the invention, the oxygen concentration during sintering for cyanogen removal is typically, but not limited to, 20%, 30%, 40%, 50%, 60%, 70%, 80%, 90% or 100%.

Preferably, the oxygen concentration is greater than 20%.

In some preferred embodiments of the invention, the oxygen concentration during sintering for cyanogen removal is typically, but not limited to, 30%, 40%, 50%, 60%, 70%, 80%, 90% or 100%.

Further, the temperature for removing cyanogen by sintering is 950-1100 ℃.

In some embodiments of the invention, the temperature at which sintering removes cyanogen is typically, but not limited to, 950 ℃, 1000 ℃, 1050 ℃, or 1100 ℃.

Preferably, the pressure for removing cyanogen by sintering is-100-0 Pa.

In some embodiments of the invention, the pressure at which the sintering removes cyanogen is typically, but not limited to, 0Pa, -10Pa, -20Pa, -30Pa, -40Pa, -50Pa, -60Pa, -70Pa, -80Pa, -90Pa or-100 Pa.

Preferably, the sintering time for removing cyanogen is 24-36 h.

In some embodiments of the invention, the time for sintering to remove cyanogen is typically, but not limited to, 24h, 25h, 26h, 27h, 28h, 29h, 30h, 31h, 32h, 33h, 34h, 35h or 36 h.

Furthermore, the water content of the cyanided sludge is 15-50%, and the cyanide content is 5-60 mg/kg.

In some embodiments of the invention, the water content of the cyanidation sludge is typically, but not limited to, 15%, 20%, 30%, 40% or 50%. When the water content of the cyanide sludge is lower than 15% or higher than 50%, the cyanide sludge cannot be molded by mixing with combustible. When the water content in the cyanide sludge is higher than 50%, water is drained in a filter pressing dry draining mode, and the water content is controlled to be 15-50% for reuse.

In some embodiments of the invention, cyanide content is typically, but not limited to, 5mg/kg, 10 mg/kg, 15 mg/kg, 20 mg/kg, 30 mg/kg, 40 mg/kg, 50 mg/kg or 60 mg/kg.

Preferably, the cyanide sludge and the combustible are uniformly mixed and formed into a wet blank, and then sintering is carried out.

The cyanide sludge and the combustible are stirred and mixed uniformly by a mixing and forming device, and are sintered after being made into a wet blank.

Preferably, the combustible comprises at least one of coal gangue, coal fines, gasified slag or slag.

In a preferred embodiment of the invention, the combustible is a solid, i.e. a solid substance. Because the solid combustible substance is helpful for the molding of the cyanide sludge, the later sintering is convenient. The combustible is preferably selected from coal gangue, coal powder, gasified slag or furnace slag, and the thermal value waste materials of the coal gangue, the coal powder, the gasified slag or the furnace slag can not only comprehensively utilize resources and protect the environment, but also can obtain better economic benefit.

Preferably, the mixed combustion heat quantity of the combustible is 260-280 kcal/kg.

The mixed combustion heat refers to the heat which can be provided by mixing combustible materials and cyanide sludge.

The blending combustion heat of the combustible is not in the range of 260-280 kcal/kg, which can cause the temperature to be suddenly high or low in the sintering process, and the cyanogen removing effect and the quality of the non-cyanogen brick finished product are seriously influenced. In one embodiment of the invention, the amount of heat of combustion of the combustible is typically, but not limited to, 260kcal/kg, 270kcal/kg or 280 kcal/kg.

Preferably, the particle size of the combustible is less than or equal to 2 mm.

When the grain diameter of the combustible substance is larger than 2mm, the compactness is influenced in the wet blank forming process, and the cyanide-free brick obtained by sintering has large cavities, so that the compressive strength of the sintered brick is reduced.

After the combustible material and the cyanide sludge are uniformly mixed, air can be discharged to the maximum extent in the forming process, so that the wet blank has high compactness, and the strength of the cyanide-free brick after sintering is higher. In some embodiments of the invention, the forming means is typically, but not limited to, compression forming or extrusion forming.

Further, the mass ratio of the cyanide sludge to the combustible in the wet blank is 70-95: 5-30.

In some embodiments of the invention, the mass ratio of cyanided sludge to combustible in the wet blank is typically, but not limited to, 70:30, 75:25, 80:20, 85:15 or 95: 5.

Preferably, the molding pressure is 1-4 MPa.

In some embodiments of the invention, the molding pressure is typically, but not limited to, 1MPa, 2MPa, 3MPa or 4 MPa.

Further, the drying and dehydration of the wet blank are also included.

And (4) stacking the formed wet blank by a robot, and drying and dehydrating. The dried and dehydrated wet blank is a pre-sintered blank.

Preferably, the temperature of drying and dehydrating is 120-400 ℃.

The wet blank has high water content, low strength and low temperature, and when the drying and dewatering temperature is lower than 120 ℃, the wet blank is easy to be condensed to soften the blank and is not beneficial to roasting. In some preferred embodiments of the invention, the temperature for dry dewatering is typically, but not limited to, 120 ℃, 150 ℃, 200 ℃, 250 ℃, 300 ℃, 350 ℃ or 400 ℃.

Preferably, the pressure of drying and dewatering is-90-0 Pa.

In some embodiments of the invention, the pressure for dry dewatering is typically, but not limited to, 0Pa, -10Pa, -20Pa, -30Pa, -40Pa, -50Pa, -60Pa, -70Pa, -80Pa or-90 Pa.

If the moisture content of the pre-sintered blank is high, the strength of the blank is too low to bear the weight of the blank stack, and the moisture generated by sintering can cause the blank to be condensed and become soft and collapse. Therefore, the water content of the pre-sintered compact should be 6% or less.

According to a second aspect of the invention, the cyanide-free brick is prepared by the cyanide sludge sintering cyanogen removal process provided by the first aspect.

According to the third aspect of the invention, the cyanide sludge sintering cyanogen removal system comprises a mixing forming device, a closed drying kiln and a closed sintering kiln which are sequentially connected.

The cyanide sludge sintering and cyanogen removing system provided by the invention has low comprehensive energy consumption and disposal cost. The tail gas collecting device is arranged in the system, so that the escape of cyanide is avoided in the process, the safety of the whole system is guaranteed, cyanide-free brick products can be obtained, and the system has good environmental benefit and economic benefit.

The sintering process completely depends on the heat released by the self combustion of the combustible to ensure the baking of the green brick.

Preferably, the tail gas collecting device is further included.

Preferably, the mixed forming device, the closed drying kiln and the closed sintering kiln are communicated with a tail gas collecting device.

Waste gas or evaporated water vapor generated in the cyanide sludge sintering and cyanogen removing system is connected with the tail gas collecting device, so that escape of cyanide is avoided in the process, and the safety of an operator is ensured.

The mixed forming device is a negative pressure device, and evaporated water vapor is introduced into the tail gas collecting device.

The negative pressure as used herein means a state lower than atmospheric pressure.

Preferably, the tail gas collecting device comprises an alkali liquor absorption tank.

The toxic substance cyanide generates the highly toxic gas hydrogen cyanide when meeting acid, and the cyanide is easily dissolved in water and can stably exist in an alkaline environment, so that the generation of the highly toxic gas hydrogen cyanide can be avoided by adopting alkali liquor protection.

Preferably, the lye of the lye absorption tank comprises a sodium hydroxide solution.

Preferably, the concentration of the sodium hydroxide solution is 5-10 g/L.

In some embodiments of the invention, the concentration of the sodium hydroxide solution is typically, but not limited to, 5g/L, 6g/L, 7g/L, 8g/L, 9g/L, or 10 g/L.

In some embodiments of the invention, the closed drying kiln and the closed sintering kiln are connected into a whole, hot air is extracted from a cooling zone of the closed sintering kiln to dry wet blanks in the closed drying kiln, and the waste heat of the closed sintering kiln is fed back to the closed drying kiln for secondary utilization, so that the waste caused by energy discharge is avoided.

In a preferred embodiment of the invention, the cyanogen-containing alkali liquor in the alkali liquor absorption tank is returned to the mixing and forming device, mixed with cyanided sludge and combustible materials, prepared into a blank and sintered to remove cyanides. Or the cyanogen-containing alkali liquor is recycled and added with oxidant to remove cyanogen, and the alkali liquor after cyanogen removal is recycled.

The cyanide sludge sintering cyanide removal process or the cyanide sludge sintering cyanide removal system provided by the fourth aspect of the invention is applied to treatment of cyanide sludge.

Some embodiments of the present invention will be described in detail below with reference to examples. The embodiments described below and the features of the embodiments can be combined with each other without conflict.

Example 1

The embodiment provides a cyanide-free brick sintered by cyanide sludge, and the technical process is shown in figure 1 and comprises the following specific processes:

(1) the coal gangue and the coal powder are crushed to be less than 2mm and are uniformly mixed to obtain the combustible. And taking newly discharged cyanide sludge for later use, wherein the water content of the cyanide sludge is 25 percent, and the cyanide content is 22.1 mg/kg.

(2) And extruding and molding the cyanide sludge and the combustible material by a mixed extrusion molding machine according to the mass ratio of 70:30 to obtain a wet blank, wherein the extrusion molding pressure is 3 MPa.

(3) The wet blanks are alternately stacked on a kiln car through a robot, and are conveyed to a closed drying kiln through a rail for drying and dehydration. The temperature of the closed drying kiln is 250 ℃, the drying and dehydrating pressure is-80 Pa, and when the moisture content in the wet blank is reduced to below 6 percent, a pre-sintered blank is obtained.

(4) And conveying the pre-sintered blank into a closed sintering kiln through a rail, wherein the oxygen content in the kiln is 20%, the sintering temperature is 1050 ℃, the sintering time is 26h, and the pressure during sintering is-100 Pa, and sintering to obtain the cyanide-free brick.

(5) In the process, the mixing and extrusion molding machine, the closed drying kiln and the closed sintering kiln are connected with an alkali liquor absorption tank, 8g/L of sodium hydroxide solution is filled in the alkali liquor absorption tank, and the sodium hydroxide solution containing cyanide returns to the mixing and extrusion molding machine for batching.

Example 2

The embodiment provides a cyanide-free brick sintered by cyanide sludge, which is different from the embodiment 1 in that the oxygen content in a closed sintering kiln is 10%, and other steps and process conditions are the same as those in the embodiment 1 and are not described again.

Example 3

The embodiment provides a cyanide-free brick sintered by cyanide sludge, which is different from the embodiment 1 in that the oxygen content in a closed sintering kiln is 5%, and other steps and process conditions are the same as those in the embodiment 1 and are not described again.

Example 4

The embodiment provides a cyanide-free brick sintered by cyanide sludge, which is different from the brick in the embodiment 1 in that the content of cyanide in cyanide sludge is 30.5mg/kg, the mass ratio of cyanide sludge to combustible is 85:15, the sintering temperature is 950 ℃, the sintering time is 24h, other steps and process conditions are the same as those in the embodiment 1, and further description is omitted.

Example 5

The embodiment provides a cyanide-free brick sintered by cyanide sludge, which is different from the embodiment 1 in that the water content of the cyanide sludge is 20%, the cyanide content is 37.2mg/kg, the mass ratio of the cyanide sludge to combustible is 75:25, the temperature of a closed drying kiln is 150 ℃, the sintering temperature is 950 ℃, the sintering time is 20 hours, the pressure during sintering is-90 Pa, and other steps and process conditions are the same as those in the embodiment 1 and are not repeated herein.

Example 6

The present example provides a cyanide-free brick sintered by cyanide sludge, which is different from example 1 in that the mass ratio of cyanide sludge to combustible is 50:50, and other steps and process conditions are the same as those in example 1, and are not described herein again.

Example 7

The present example provides a cyanide-free brick sintered by cyanide sludge, which is different from example 1 in that the mass ratio of cyanide sludge to combustible is 95:5, and other steps and process conditions are the same as those in example 1, and are not described herein again.

Example 8

The present embodiment provides a cyanide-free brick sintered by cyanide sludge, which is different from embodiment 1 in that the water content of cyanide sludge is 15%, the cyanide content is 60mg/kg, and other steps and process conditions are the same as those in embodiment 1, and are not described herein again.

Example 9

The present embodiment provides a cyanide-free brick sintered by cyanide sludge, which is different from embodiment 1 in that the water content of cyanide sludge is 50%, the cyanide content is 60mg/kg, and other steps and process conditions are the same as those in embodiment 1, and are not described herein again.

Example 10

The present embodiment provides a cyanide-free brick sintered by cyanide sludge, which is different from embodiment 1 in that the sintering temperature is 600 ℃, the sintering time is 40 hours, and other steps and process conditions are the same as those in embodiment 1, and are not described herein again.

Example 11

The present embodiment provides a cyanide-free brick sintered by cyanide sludge, which is different from embodiment 1 in that the sintering temperature is 1300 ℃, the sintering time is 15 hours, and other steps and process conditions are the same as those in embodiment 1, and are not described herein again.

Test example 1

The cyanide content, compressive strength and water absorption of the cyanide-free bricks obtained in examples 1 to 11 were measured by the following methods:

determination of cyanide content: measured according to "measurement spectrophotometry for soil cyanide and Total cyanide" of HJ 745-2015, the cyanide original content M₀Final content of cyanide M₁The cyanide decomposition rate was calculated by the formula (1).

Formula (1)

And (3) testing the compressive strength: the non-cyanide brick is sawed into two half bricks, and the length of the half bricks is not less than l00 mm. And (3) putting the disconnected half-brick on a test piece preparation platform into clean water at room temperature, soaking for 10-20min, taking out, stacking in the direction opposite to the section, smearing No. 325 ordinary portland cement paste with the thickness not more than 5mm between the half-brick and the test piece preparation platform, plastering the upper surface and the lower surface with the same kind of cement paste with the thickness not more than 3mm, and maintaining for three days at room temperature. And recording the maximum failure load P of the pressure tester to be accurate to 0.1 MPa.

The tester is NYL-300 type pressure tester with a pressurizing rate of 5 multiplied by 10³N/s. The formula of the compressive strength is as follows:

formula (2)

In formula (2):

f is compressive strength (MPa); p is the breaking load (KN); a is the area (mm) under pressure²)。

Water absorption test: weighing the cyanide-free brick m₀Then immersing the sintered brick into water with the water temperature of 10-30 ℃, taking out the sintered brick after 24 hours to wipe off the surface moisture, and immediately weighing m₂₄. The water absorption was calculated by the formula (3).

Formula (3)

TABLE 1 cyanide-free brick Performance data sheet

Numbering	Original content of cyanide (mg/kg)	Final cyanide content (mg/kg)	Cyanide decomposition rate (%)	Compressive strength (MPa)	Water absorption (%)
						Example 1	22.1	0.0021	99.99	7.89	15.2
Example 2	22.1	0.0033	99.99	7.21	16.1
						Example 3	22.1	0.0081	99.96	6.98	16.9
Example 4	37.2	0.0053	99.97	7.33	15.9
						Example 5	30.5	0.0033	99.98	7.57	15.0
Example 6	22.1	0.0022	99.99	2.97	34.6
						Example 7	22.1	0.0012	99.96	7.71	14.9
Example 8	60	0.0101	99.98	7.84	15.7
						Example 9	60	0.0092	99.98	7.88	15.5
Example 10	22.1	0.0092	99.96	3.27	26.1
						Example 11	22.1	0.0009	99.99	8.09	14.3

According to the embodiment and the data in the table 1, the cyanide removal rate of the cyanide sludge sintering cyanide removal process provided by the invention reaches more than 99.96%, industrial waste with a calorific value is used for completing sintering in the process, the waste heat of a sintering kiln can be recycled, and the comprehensive energy consumption and the disposal cost are low; the process has high degree of mechanization and low labor cost, the final product is harmless to the environment, the cyanogen-free brick with economic value is obtained, the defects in the prior art are alleviated, and the method is suitable for large-scale application in the field of metal tailing treatment.

Finally, it should be noted that: the above embodiments are only used to illustrate the technical solution of the present invention, and not to limit the same; while the invention has been described in detail and with reference to the foregoing embodiments, it will be understood by those skilled in the art that: the technical solutions described in the foregoing embodiments may still be modified, or some or all of the technical features may be equivalently replaced; and the modifications or the substitutions do not make the essence of the corresponding technical solutions depart from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A cyanide sludge sintering decyanation process is characterized in that cyanide sludge and combustible are uniformly mixed and formed into wet blanks, the wet blanks are dried and dehydrated to obtain pre-sintered blanks, and then sintering decyanation is carried out to obtain non-cyanide bricks;

wherein the water content in the cyanided sludge is 15-50%;

the cyanide content in the cyanided sludge is 5-60 mg/kg;

the mass ratio of the cyanide sludge to the combustible in the wet blank is 70-95: 5-30;

the combustible comprises at least one of coal gangue, coal powder, gasified slag or furnace slag;

the mixed combustion heat quantity of the combustible is 260-280 kcal/kg;

the oxygen concentration is more than 10% during the sintering decyanation;

the drying and dehydrating temperature is 120-400 ℃;

the water content of the pre-sintered compact is less than or equal to 6 percent.

2. The cyanide sludge sintering cyanogen removal process according to claim 1, wherein the temperature of the sintering cyanogen removal is 950 to 1100 ℃.

3. A cyanide-free brick, characterized in that it is prepared by the cyanide sludge sintering cyanide removal process according to claim 1 or 2.

4. The cyanide sludge sintering cyanogen removal system using the process of claim 1, which is characterized by comprising a mixing and forming device, a closed drying kiln and a closed sintering kiln which are connected in sequence.

5. The cyanide sludge sintering decyanation system of claim 4, wherein a lye absorption tank is connected to the mixing and shaping device to transport lye in the lye absorption tank to the mixing and shaping device.

6. Use of the cyanide sludge sintering decyanation process of claim 1 or 2 or the cyanide sludge sintering decyanation system of claim 4 or 5 in the treatment of cyanide sludge.