阅读说明：本技术 一种高砷金精矿脱硫、脱砷回收金、银的工艺方法 (Process method for recovering gold and silver by desulfurization and dearsenification of high-arsenic gold concentrate ) 是由 王志强 杜子益 丁重云 于 2021-07-30 设计创作，主要内容包括：本发明公开了一种高砷金精矿脱硫、脱砷回收金、银的工艺方法,涉及湿法冶金领域。本发明本发明是利用原两段焙烧系统进行技术改造,既利用了原有设备,又降低了资金投入；原200t/d的焙烧系统投矿量约为180t/d,改造后投矿量可达到240-250t/d；焙烧渣直接进入火法冶炼金的综合回收率可达到95%以上,经济效益可观,扩大了原料采购方面的竞争优势,此过程不再有废水和危险废物产生,满足国家环保要求。(The invention discloses a process method for recovering gold and silver by high-arsenic gold concentrate desulfurization and dearsenification, and relates to the field of hydrometallurgy. The invention carries out technical transformation by utilizing the original two-section roasting system, not only utilizes the original equipment, but also reduces the capital investment; the ore feeding amount of the original roasting system of 200t/d is about 180t/d, and the ore feeding amount after modification can reach 240t/d and 250 t/d; the comprehensive recovery rate of the roasting slag directly entering the pyrometallurgical metallurgy can reach more than 95 percent, the economic benefit is considerable, the competitive advantage in the aspect of raw material purchasing is enlarged, no wastewater and hazardous waste are generated in the process, and the national environmental protection requirement is met.)

1. A process method for recovering gold and silver by high-arsenic gold concentrate desulfurization and dearsenification is characterized by comprising the following steps:

(1) connecting two sections of furnaces of the original two-section roasting in parallel and simultaneously feeding, and carrying out weak-oxygen rapid roasting on the ore pulp to remove arsenic;

(2) when the temperature of the tail gas generated in the step (1) is controlled to be 500 ℃, supplementing air for secondary combustion, and oxidizing arsenic sulfide;

(3) dedusting and purifying the flue gas generated in the step (2), and then converting the flue gas and entering a dry absorption section for acid making;

(4) cooling the tailings obtained in the step (1) through water extraction, and dehydrating through a filter press to obtain roasted gold concentrate;

(5) the roasted gold concentrate is smelted by a pyrometallurgical process, and precious metals such as gold and silver are recovered.

2. The process method for recovering gold and silver by desulfurization and dearsenification of high-arsenic gold concentrate according to claim 1, which is characterized in that: the furnace temperature of the two furnaces for weak oxygen fast roasting arsenic removal in the step (1) is controlled at 620 +/-10 ℃.

3. The process method for recovering gold and silver by desulfurization and dearsenification of high-arsenic gold concentrate according to claim 1, which is characterized in that: and (3) in the step (2), the secondary combustion chamber is arranged, and a proper amount of air is supplemented into the secondary combustion chamber, so that the arsenic sulfide is arsenic oxide and sulfur dioxide.

4. The process method for recovering gold and silver by desulfurization and dearsenification of high-arsenic gold concentrate according to claim 1, which is characterized in that: when the dry absorption section is used for preparing acid, the surface cooler is used for cooling the flue gas in advance, and the temperature of acid absorption is reduced.

5. The process method for recovering gold and silver by desulfurization and dearsenification of high-arsenic gold concentrate according to claim 1, which is characterized in that: the dry absorption section uses the production water to cool the softened water of the closed cycle, and the softened water of the closed cycle carries out heat exchange cooling on the sulfuric acid.

6. The process method for recovering gold and silver by desulfurization and dearsenification of high-arsenic gold concentrate according to claim 1, which is characterized in that: the roasting yield of the weak oxygen rapid roasting step is 70-75%.

Technical Field

The invention relates to the field of wet metallurgy, in particular to a process method for recovering gold and silver by desulfurizing and dearsenifying high-arsenic gold concentrate.

Background

The existing treatment method of high-arsenic gold concentrate is mainly a BASF two-stage method, namely a method commonly called two-stage roasting cyaniding gold and silver recovery method), the recovery rate of gold is generally 75% -85%, the recovery rate is not very high, along with the competition of the market, the ore purchasing cost is higher and higher, the enterprise benefit is lower and lower, most two-stage roasting enterprises stop production or are transformed at present, the cyanided tailings belong to hazardous waste HW33, the environmental protection pressure is very high at present, the national management on the hazardous waste is very strict, the disposal and transfer of the hazardous waste need to invest very large funds, and the high-arsenic ore cannot directly enter pyrometallurgical smelting due to the high arsenic content.

Disclosure of Invention

The invention aims to provide a process method for recovering gold and silver by desulfurizing and dearsenifying high-arsenic gold concentrate, which utilizes the original two-section roasting system to upgrade and reform, improves the original productivity, improves the recovery rate of gold and silver, and solves the problem of cyaniding tailings of hazardous wastes at the same time

In order to realize the effect, the invention discloses a process method for recovering gold and silver by high-arsenic gold concentrate desulfurization and dearsenification, which comprises the following steps:

(1) connecting two sections of furnaces of the original two-section roasting in parallel and simultaneously feeding, and carrying out weak-oxygen rapid roasting on the ore pulp to remove arsenic;

(2) when the temperature of the tail gas generated in the step (1) is controlled to be 500 ℃, supplementing air for secondary combustion, and oxidizing arsenic sulfide;

(3) dedusting and purifying the flue gas generated in the step (2), and then converting the flue gas and entering a dry absorption section for acid making;

(4) cooling the tailings obtained in the step (1) through water extraction, and dehydrating through a filter press to obtain roasted gold concentrate;

(5) the roasted gold concentrate is smelted by a pyrometallurgical process, and precious metals such as gold and silver are recovered.

Further, the furnace temperature of the two furnaces for removing arsenic by weak-oxygen rapid roasting in the step (1) is controlled at 620 ℃ +/-10 ℃. Two furnaces which are originally connected in series are changed into parallel connection, the two furnaces feed from the top of the furnace at the same time, and the ore charging amount, the air volume and the ore discharging speed of the two furnaces are controlled, so that the temperature and the bottom pressure of the two furnaces are controlled, wherein the bottom pressure of the No. 1 furnace is controlled to 20000-;

furthermore, in the step (2), a secondary combustion chamber is arranged, and a proper amount of air is supplemented into the secondary combustion chamber, so that the arsenic sulfide is arsenic oxide and sulfur dioxide.

Furthermore, when the dry absorption section is used for preparing acid, the surface cooler is used for cooling the flue gas in advance, and the temperature of acid absorption is reduced.

Furthermore, the dry absorption section uses the production water to cool the softened water of the closed cycle, and the softened water of the closed cycle carries out heat exchange and cooling on the sulfuric acid.

Further, the roasting yield of the weak oxygen rapid roasting step is 70-75%.

The invention has the beneficial effects that:

(1) the invention carries out technical transformation by utilizing the original two-section roasting system, not only utilizes the original equipment, but also reduces the capital investment;

(2) the ore feeding amount of the original roasting system of 200t/d is about 180t/d, and the ore feeding amount after modification can reach 240t/d and 250 t/d;

(3) the comprehensive recovery rate of the roasting slag directly entering the pyrometallurgical metallurgy can reach more than 95 percent, the economic benefit is considerable, the competitive advantage in the aspect of raw material purchasing is enlarged, no wastewater and hazardous waste are generated in the process, and the national environmental protection requirement is met.

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 embodiments. It is to be understood that the embodiments described are only a few embodiments of the present invention, and not all embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

A process method for recovering gold and silver by high-arsenic gold concentrate desulfurization and dearsenification comprises the following steps:

(1) connecting two sections of furnaces of the original two-section roasting in parallel and simultaneously feeding, and carrying out weak-oxygen rapid roasting on the ore pulp to remove arsenic;

(2) when the temperature of the tail gas generated in the step (1) is controlled to be 500 ℃, supplementing air for secondary combustion, and oxidizing arsenic sulfide;

(3) dedusting and purifying the flue gas generated in the step (2), and then converting the flue gas and entering a dry absorption section for acid making;

(4) cooling the tailings obtained in the step (1) through water extraction, and dehydrating through a filter press to obtain roasted gold concentrate;

(5) the roasted gold concentrate is smelted by a pyrometallurgical process, and precious metals such as gold and silver are recovered.

A specific embodiment:

(1) the raw materials are mixed into ore pulp with the concentration of about 70 percent, the ore pulp is sent to two furnaces through a pump, and the materials are fed in a furnace top feeding mode;

(2) controlling the ore feeding amount, the air quantity and the ore discharge speed, wherein the 1# ore feeding amount is about 7.5t/h, the average furnace temperature is 613 ℃, the furnace bottom pressure is 22400Pa, the 2# furnace ore feeding amount is about 2.5t/h, the average temperature is 622 ℃, the furnace bottom pressure is 13600Pa, and the total ore feeding amount is about 240 t/d;

(3) the temperature of the sulfuric acid passing through the plate heat exchanger was as follows:

the temperature of the drying plate for exchanging the inlet acid is 63 ℃, the temperature of the plate for exchanging the outlet acid is 45 DEG C

The temperature of acid exchange of one suction plate into the plate is 75 ℃, the temperature of acid exchange of the plate out of the plate is 62 DEG C

The acid inlet temperature of the two suction plates is 82 ℃, the acid outlet temperature of the two suction plates is 65 DEG C

Ensuring that qualified sulfuric acid products are produced, and the yield of the sulfuric acid is about 150t/d

(4) Water quenching the roasting slag, rapidly cooling, and dehydrating by a filter press;

(5) the roasting slag enters a pyrometallurgical system, and the pyrometallurgical recovery rate is stable and can reach more than 95%.

Analysis of composition

TABLE 1 analysis of raw ore composition

Note: au, Ag content unit is g/t, and the content units of the other elements are%

TABLE 2 analysis of the composition of the roasting slag

No loss of noble metal occurs during the firing process.

The above-mentioned embodiments are merely illustrative of the preferred embodiments of the present invention, and do not limit the scope of the present invention, and various modifications and improvements of the technical solution of the present invention by those skilled in the art without departing from the spirit of the present invention should fall within the protection scope defined by the claims of the present invention.