WO2019210534A1

WO2019210534A1 - Method for preparing sulphoaluminate cement by using cyanide tailings

Info

Publication number: WO2019210534A1
Application number: PCT/CN2018/087139
Authority: WO
Inventors: 董凯伟; 谢锋; 王伟; 路殿坤; 王剑; 符岩; 畅永锋
Original assignee: 东北大学
Priority date: 2018-05-02
Filing date: 2018-05-16
Publication date: 2019-11-07
Also published as: CN108275896A; CN108275896B

Abstract

A method for preparing aluminosulfate cement using cyanide tailings, comprising the following steps: (1) preparing cyanide tailings, lime and an aluminum material as raw materials, and adding or not adding a mineralizer to prepare a mixed material; (2) performing high-temperature sintering by means of a high-temperature kiln to obtain sintered clinker; and (3) cooling the same to room temperature by means of a cooling kiln, and performing cement powder grinding treatment to prepare aluminosulfate cement. The method has a good cyanide removal effect and has a cyanide removal rate of 99% or more. The high-temperature sintered aluminosulfate cement is a high-strength and fast-hardening cement, and can fully meet the required cement amount for capital construction and backfilling of gold ore enterprises.

Description

Method for preparing sulphoaluminate cement by using cyanide tailings

Technical field

The invention relates to the field of non-ferrous metallurgy technology and environmental protection technology, in particular to a method for preparing sulphoaluminate cement by using cyanide tailings.

Background technique

Because gold mines use cyanide gold extraction technology in the production process, a large amount of cyanide tailings are produced. These cyanide tailings contain a large amount of pollutants such as sulfur, copper, arsenic, mercury and highly toxic cyanide. . In addition to the small amount of cyanide tailings that can be utilized, a considerable amount of cyanide tailings is only stored and disposed of, not only occupying a large amount of land resources, but also has hidden dangers of polluting surface water, groundwater and soil, and generating extremes to the surrounding environment. Large safety hazards and environmental hazards; at present, cyanide tailings have been listed as HW33 hazardous wastes in the National Hazardous Waste List by the state. The pollution characteristics are obvious and the pollution is serious. The environmental pressures of the state and enterprises have increased sharply and urgently need to be taken. Practical control techniques to eliminate the environmental hazards of such hazardous waste.

At present, the technology for treating cyanide tailings is mainly flotation, supplemented by autoclaving, chlorination roasting, molten salt roasting, reduction roasting, oxidation, solidification, preparation of Portland cement, preparation of bricks and blocks, etc., flotation (CN201410228170.5, CN201410099597.X, CN201510055236.X) multi carried out under weakly acidic conditions, under these conditions, CN ^- unstable, resulting in poor working conditions, and subject to multiple floating Selective treatment; autoclave method (CN201510023812.2) is mainly carried out in autoclave or autoclave, it takes a long time to maintain pressure at high temperature, and needs to deal with secondary pollution caused by autoclaving; chlorination roasting method (CN201410317041.3, CN201410757942.4) is mainly a method of mixing chlorinating agent and the cyanide tailings with high-temperature roasting, which has high requirements on equipment anti-corrosion ability and high energy consumption; molten salt roasting method (CN201410317042.8, CN201611121854.0) adopts melting The salt or molten pool is calcined with cyanide residue, the calcination temperature is higher and the time is longer; the reduction roasting method (CN201610825331.8, CN201610846576.9) adopts a reducing agent to reduce at a high temperature, and the reduction time is longer; the oxidation method (CN201711048319. 1) Adopt ozone, double Water, sodium hypochlorite and other oxidants oxidize cyanide tailings, the operating cost is higher; curing method (CN201710628397.2) uses a curing agent to solidify cyanide slag, but can not fundamentally solve the possible environmental pollution caused by cyanide tailings; preparation Portland cement (CN201210002870.3, Kong Yapeng-Cyanide tailings comprehensive utilization of valuable elements [D]. Northeastern University, 2014), using ordinary cyanide tailings with high aluminum and silicon content to prepare ordinary Portland cement Preparation of bricks (CN201110116703.7, Zhu Mincong, etc., using gold mine tailings to make building materials autoclaved bricks process research [J]. Mineral comprehensive utilization, 2008 (1): 43-46, CN200410036554.3) using cyanidation The preparation of autoclaved bricks, permeable bricks and concrete blocks by tailings, active agents and additives requires high temperature and long-term autoclaving or incomplete cyanide destruction.

The existing methods or energy consumption are high or accompanied by secondary pollution or incomplete cyanide production or complex process, high operating costs; therefore, for cyanide tailings, there is currently a lack of local conditions for this type of hazardous waste. Reasonable and effective treatment.

Summary of the invention

In view of the above-mentioned deficiencies in the current cyanide tailings technology, the present invention provides a method for preparing sulphoaluminate cement by using cyanide tailings, which is processed by high-temperature sintering with aluminum material and lime, and is processed based on local materials. The effect is stable, the product is self-use, and easy to promote.

The method of the invention comprises the following steps:

(1) Preparing cyanide tailings, lime and aluminum materials as raw materials, mixing all the raw materials uniformly, adding or not adding mineralizer to make a mixture; in all the raw materials, cyanide tailings 4~ by mass parts 5 parts, 10 to 25 parts of lime, 8 to 30 parts of aluminum material; the amount of mineralizer added is 0 to 5% of the total mass of all raw materials; the mineralizer is selected from fluorite or B ₂ O ₃ The aluminum material used is bauxite or fly ash;

(2) The mixture material is sintered at a high temperature in a high temperature furnace, the sintering temperature is 1200 to 1500 ° C, and the time is 10 to 180 minutes to obtain a sintered clinker; the atmosphere is an oxidizing atmosphere at a high temperature sintering;

(3) The sintered clinker is cooled to a normal temperature by a cooling kiln, and then subjected to cement grinding treatment to prepare a sulphoaluminate cement.

The solid content of the above cyanide tailings contains Fe 10 to 45%, S 11 to 51%, SiO ₂ 4 to 55%, Al ₂ O ₃ 1 to 10%, CaO 0.4 to 5%, and CN ^— by mass percentage ^. The content is 50 to 2500 mg/kg.

In the above method, in step (1), before cyanide tailings, lime and aluminum materials are mixed, they are respectively crushed to a particle diameter of 2 to 5 mm, and then respectively ground to a particle diameter of -0.074 mm, which accounts for 85% of the total weight. the above.

In the above method, the high temperature furnace is selected from a rotary kiln or a vertical kiln.

In the above method, the oxidizing atmosphere is selected from an air atmosphere.

In the above method, the step (3) is controlled by the cooling kiln to control the average cooling rate to be 15 to 40 ° C / min.

The invention has the beneficial effects that: the cyanidation tailings are cleaned and transformed by the high temperature weak oxidizing atmosphere sintering, the cyanide removal efficiency is good, and the cyanide breaking rate is over 99%; the mineralizer is used to reduce the clinker sintering temperature and increase the clinker Easy to burn performance; lime can fix part of cyanide in cyanide tailings and SO ₂ after sulfide oxidation to avoid environmental pollution during sintering; high temperature sintering cyanogen is independent of initial concentration of cyanide, related to time and temperature, The sulphoaluminate cement after high-temperature sintering is high-strength and fast-hardening cement, which can fully meet the cement construction amount and backfilling amount of gold ore enterprises.

DRAWINGS

1 is a schematic flow chart of a process for preparing sulphoaluminate cement by using cyanide tailings according to the present invention.

detailed description

The cyanidation tailings in the embodiment of the invention are all mud cyanidation tailings or direct gold cyanide slag in the cyanidation gold extraction process.

The whole mud cyanide tailings or gold concentrate direct cyanide slag in the embodiment of the invention is an aqueous cyanide tailings formed by pressure filtration to a water content of <30%, and the hydration time is continued at any time, and the water gradually decreases. The aqueous cyanide tailings are dried to remove moisture before use.

The fluorite, B ₂ O ₃ , bauxite and fly ash used in the examples of the present invention are commercially available industrial grade products.

The fluorite and B ₂ O ₃ used in the examples of the present invention are first broken to a particle diameter of 2 to 5 mm, and further ground to a particle diameter of -0.074 mm, which accounts for more than 85% of the total mass.

The bauxite used in the embodiment of the present invention contains Al ₂ O ₃ 62.36%, SiO ₂ 11.64%, Fe ₂ O ₃ 5.77%, TiO ₂ 2.50%, CaO 0.42% by mass percentage; fly ash contains Al by mass percentage. ₂ O ₃ 48.62%, SiO ₂ 38.26%, Fe ₂ O ₃ 1.82%, TiO ₂ 1.55%, CaO 1.87%.

In the embodiment of the invention, the cyanide removal rate is ≥99%.

In the embodiment of the present invention, the temperature increase rate is controlled to be 5 to 15 ° C/min when the temperature is raised by high temperature sintering.

In the method of the invention, the tail gas generated by sintering is discharged after being subjected to dust removal, desulfurization and denitration treatment to meet the national standard.

In the embodiment of the present invention, the cement grinding treatment is carried out by using a pre-grinding system-finish grinding system.

The technical solutions of the present invention are further described in the following with reference to the preferred embodiments. The following examples are intended to illustrate the invention and are not intended to limit the scope of the invention.

Example 1

The cyanide tailings are cyanide tailings produced by a company in Shandong. After drying, the content includes Fe 41.41%, S 48.40%, SiO ₂ 5.72%, Al ₂ O ₃ 1.48%, CaO 0.47%, CN ^- content. 340mg/kg;

The cyanide tailings, lime and aluminum materials are respectively crushed to a particle size of 2 to 5 mm, and then respectively ground to a particle diameter of -0.074 mm, which accounts for more than 85% of the total weight;

Prepare cyanide tailings, lime and aluminum materials as raw materials, and mix all the raw materials uniformly; 4 parts of cyanidation tailings, 18 parts of lime and 20 parts of aluminum materials in all the raw materials; The material is bauxite;

The mixture material is sintered at a high temperature in a high temperature furnace, the high temperature furnace is a rotary kiln, the sintering temperature is 1300 ° C, the time is 60 min, and the sintered clinker is obtained; the atmosphere is an air atmosphere during high temperature sintering;

The sintered clinker is cooled to a normal temperature by a cooling kiln, and the average cooling rate is controlled to be 15 ° C / min, and then subjected to cement grinding treatment to prepare a sulphoaluminate cement;

After testing found not detected in the sintered clinker CN ^-, cyano break rate (to CN ^- basis) more than 99%; S loss before and after sintering of <5%, the main phase was sintered sulphoaluminate clinker The cement phase; the prepared sulphoaluminate cement is made into concrete according to the standard GB/T 17671, and is cured for 28 days, and the strength fully meets the cement requirement of No. 425.

Example 2

The method is the same as that in Embodiment 1, except that:

(1) Cyanide after drying mass percent slag containing Fe 29.92%, S 33.30%, SiO 2 24.95%, Al 2 O 3 5.25%, CaO 1.15%, CN - content of 500mg / kg;

(2) Among all the raw materials, 5 parts of cyanide tailings by mass fraction, 17 parts of lime and 30 parts of aluminum material; the aluminum material is fly ash;

(3) The high temperature furnace is a vertical kiln, the sintering temperature is 1300 ° C, the time is 60 min; the controlled average cooling rate is 20 ° C / min.

Example 3

The method is the same as that in Embodiment 1, except that:

(1) Cyanide after drying mass percent slag containing Fe 16.37%, S 16.50%, SiO 2 41.96%, Al 2 O 3 9.71%, CaO 2.10%, CN - content of 1200mg / kg;

(2) Among all the raw materials, 5 parts of cyanide tailings by mass fraction, 11 parts of lime and 8 parts of aluminum material;

(3) Sintering temperature 1300 ° C, time 60 min; controlled average cooling rate was 25 ° C / min.

Example 4

The method is the same as that in Embodiment 1, except that:

(1) Mix all the raw materials and add mineralizer; in all the raw materials, 4.5 parts of cyanide tailings by mass, 25 parts of lime, and 16 parts of aluminum material; the amount of mineralizer added accounts for the total mass of all raw materials. 3%; the mineralizer is fluorite;

(2) The high temperature furnace is a vertical kiln, the sintering temperature is 1200 ° C, the time is 180 min; the control average cooling rate is 30 ° C / min.

Example 5

The method is the same as that of Embodiment 2, and the difference lies in:

(1) Mix all the raw materials and add mineralizer; in all the raw materials, 4.5 parts of cyanide tailings by mass, 10 parts of lime, and 27 parts of aluminum material; the amount of mineralizer added accounts for the total mass of all raw materials. 5%; the mineralizer is B ₂ O ₃ , and the aluminum material is fly ash;

(2) Sintering temperature 1500 ° C, time 10 min; controlled average cooling rate was 40 ° C / min.

Claims

A method for preparing sulphoaluminate cement by using cyanide tailings, characterized by comprising the following steps:

(1) Preparing cyanide tailings, lime and aluminum materials as raw materials, mixing all the raw materials uniformly, adding or not adding mineralizer to make a mixture; in all the raw materials, cyanide tailings 4~ by mass parts 5 parts, 10 to 25 parts of lime, 8 to 30 parts of aluminum material; the amount of mineralizer added is 0 to 5% of the total mass of all raw materials; the mineralizer is selected from fluorite or B 2 O 3 The aluminum material used is bauxite or fly ash;

(2) The mixture material is sintered at a high temperature in a high temperature furnace, the sintering temperature is 1200 to 1500 ° C, and the time is 10 to 180 minutes to obtain a sintered clinker; the atmosphere is an oxidizing atmosphere at a high temperature sintering;

(3) The sintered clinker is cooled to a normal temperature by a cooling kiln, and then subjected to cement grinding treatment to prepare a sulphoaluminate cement.
The method for preparing sulphoaluminate cement by using cyanide tailings according to claim 1, wherein the cyanide tailings contain 10 to 45% by mass of Fe, and 11 to 51% by mass. SiO 2 4 ~ 55%, Al 2 O 3 1 ~ 10%, CaO0.4 ~ 5%, and CN - content of 50 ~ 2500mg / kg.
The method for preparing sulphoaluminate cement by using cyanide tailings according to claim 1, wherein in the step (1), the cyanide tailings, the lime and the aluminum material are separately crushed to the granules before being mixed. The diameter is 2 to 5 mm, and the portions which are respectively ground to a particle diameter of -0.074 mm account for 85% or more of the total weight.
The method for preparing sulphoaluminate cement by using cyanide tailings according to claim 1, wherein the high temperature furnace is selected from a rotary kiln or a vertical kiln.
A method for preparing sulphoaluminate cement using cyanide tailings according to claim 1, wherein said oxidizing atmosphere is selected from an air atmosphere.
A method for preparing sulphoaluminate cement using cyanide tailings according to claim 1, characterized in that in the step (3), the cooling rate is controlled by a cooling kiln to be 15 to 40 ° C / min.