[ni-Co-Li Summit] A brief discussion on the Solutions to the problems related to Valve Control in Industry production

From May 20 to 21, the 2021 (sixth) China International Nickel, Cobalt and Lithium Summit Forum, held by Shanghai Nonferrous Network Information Technology Co., Ltd., was held at Xinhua Lianlijing Hotel, Tongguanyao, Changsha, Hunan Province. Today, about 1000 elites of the nickel-cobalt-lithium industry, celebrities from all walks of life, and industry scholars meet again in 2021 (the sixth) China International Nickel-Cobalt-Lithium Summit Forum. On May 21, the meeting entered the China International Nickel Industry chain Summit Forum, at which Jiang Yong, South China Regional Manager / sales Minister of Viduli Valve Co., Ltd., introduced the solutions to the problems related to valve control in the production of the industry.

Development and performance introduction of flash control valve

Summary of flash control valve: aiming at the flash control valve and assembly of horizontal autoclave discharge pipe in oxygen pressure leaching hydrometallurgy, its acidic and alkaline pulp materials in the over-flow medium have the characteristics of strong abrasion, strong corrosion, easy crystallization, high solid content and harsh medium flushing working conditions, in order to meet the long-term safe and stable operation of process pipeline equipment, our company has compared and studied a large number of similar products abroad. Combined with their own long-term practical experience, fully absorb their respective advantages of the formation of a series of flash control valves with independent intellectual property rights.

Research and development of flash control valve:

The importance of flash control valve: flash control valve is used in the discharge pipe between autoclave and flash tank in oxygen pressure leaching workshop, it is the most critical flow control valve, the use of which directly affects the operation and stability of the device.

The difficulty of the flash control valve: the reaction kettle comes out of the high-temperature acid pulp under the action of high pressure difference to produce flash, the valve is very easy to be scoured and cavitation and scrapped!

Use of traditional valves:

The first kind: v-shaped ball valve

Problems: v-shaped ports and valve body passages are easily scoured and damaged.

Reason analysis: the medium directly impacts the sphere, and the material passes through the V-shaped; when the mouth is compressed, it is enhanced to scour; the service life: no more than one week.

The second kind: ceramic ball valve

Problem: ceramic seat, ball brittle

Reason analysis: ceramics withstand the vibration of non-liao pipe and the impact of slurry medium.

Service life: 2 hours

The third kind: ordinary angle valve

The fourth kind: angle valve with elbow

Common problems: 1. The spool and seat are seriously scoured and worn. 2. The inner cavity of the valve body is seriously eroded.

Cause analysis: the internal valve cavity has a right-angle structure, the straight face erosion is large, and the STL, hardness of spool and seat 904L surfacing can not meet the requirements of working conditions.

Service life: about 15 days

The key problems that can not be solved by traditional valves: strong corrosion, strong erosion, strong cavitation.

New flash control valve: more reasonable structure and breakthrough in material selection

Structural design of Viduli flash valve:

First, the valve cavity structure has a cushioning structure design: when the pulp passes through the spool, the decompression must be beneficial to the cushioning effect, and the pressure of the medium in the inner cavity will be reduced instantly, so that the slurry will not overweight erosion and wear on the valve body. (the design of the valve cavity of the flash valve is different according to the properties of the material pulp, pressure difference, temperature, solid content and other conditions in the working conditions.)

Second, the turning position design is a non-dead angle design of the throwing arc: it can keep the fluid passing smoothly and will not cause positive erosion to the shell wall and internals because of the sharp turn.

Third, guide the flow direction of the media: the cavitation caused by the high-speed flow medium is placed on the spool and the valve sleeve, because the spool seat is made of high hardness and wear-resistant materials.

Fourth, the structural design of the guide sleeve: the center of the valve stem protected by the isolation medium does not shift. Multiple spacer rings, so that the spool will not produce too much vibration, will not let the vibration affect the instrument on the device, and reduce noise. Fifth, spool and seat replaceable design: the cost of replacing spool seat is low, and the replacement is more convenient. 6. Extended seat flash control valve: the lengthened seat is mainly to protect the flash tank, so that the material can rush straight to the center of the reaction tank in one direction, so as to prevent the material from eroding the tube mouth and tank wall of the flash tank.

Innovative breakthroughs in spool and seat selection: high hardness metal hardening film treatment materials; excellent mechanical properties, high mass density, hardness between HV1300~ 1500, non-chemical reaction with sulfuric acid, very stable, erosion resistance, wear resistance and other advantages.

Summary

After years of research and development, use and transformation, the Viduli flash control system fully meets the application conditions of hydrometallurgical projects at different temperatures and pressures. at present, our company's flash control system has been used in oxygen pressure leaching workshops of 26 smelters in China. and all the indexes can meet the stringent requirements of wet smelting, and now we have fully mastered the technology of oxygen pressure leaching flash control system, so as to break the foreign monopoly of the system. Through localization can promote the upgrading of wet smelting technology!

Hard sealing ball valve and plug valve for pulp material pipeline

The main difficulties of slurry material pipeline are slurry particles, strong acid corrosion, strong erosion, easy blockage and static corrosion.

Introduction of hard seal ball valve:

First, the clearance between the valve body and the sphere is less than 0.7mm, and the inner cavity of the valve body is smooth and smooth; avoid the problem that the traditional ball valve is blocked by the medium

Second, the valve seat dustproof design: there is a dustproof device before and after the valve seat spring to prevent the spring from being blocked and invalidated.

Third, the design of the cleaning scraper of the valve seat: it can clean the crystalline particles on the surface of the sphere.

Fourth, to prevent the valve from expanding to death at high temperature: the selection of high-temperature-resistant flexible graphite imported from the United States and the use of butterfly spring structure can effectively compensate and prevent the ball valve from inflating to death.

Ball erosion resistance: square notch design: aiming at the working conditions of granular medium, high pressure and high erosion, our company has developed a unique spherical square notch structure, which increases the over-current area at the moment of opening the valve, which is 4 times larger than that of the traditional ball valve. as a result, the flow rate of the medium is reduced and the erosion of the medium to the sphere and valve seat is greatly reduced.

The ball and seat adopt the most advanced hardening technology: the ball and seat adopt the state-of-the-art supersonic flame spraying (HVOF) technology, so that the ball and seat have the advantages of high hardness, wear resistance, corrosion resistance, erosion resistance and coating does not fall off.

CNC machine plus ball grinding technology: our company's high-precision CNC ball mill rotates and grinds the ball and valve seat to achieve extremely high roundness and finish, which can not only ensure the sealing performance of the valve, but also greatly prolong the service life.

Unique sealing structure of plug valve:

1. The valve cavity adopts multi-groove flange structure, which is helpful to fix the sealing bushing and avoid valve failure caused by the displacement of valve seat driven by cock rotation.

two。 The sealing bushing is close to the valve body and cock, and there is no gap in the valve cavity: the slurry medium can not enter the valve cavity, which is not clogged and does not damage the seal.

3. Valve cavity 360 degree sealing flange: when switching, the lip edge of the flange can clean the crystal to avoid damage to the sealing bushing;

4. Three-way seal structure design: three-way seal can effectively prevent the leakage of the valve stem.

5. Bolt on-line adjustment structure: the upper seal can be directly adjusted on-line, and the compression amount of the cock can be adjusted to keep the seal in the best condition for a long time.

6. Cone design of cock: the slope is changed from 4 °to 6 °, which can effectively prolong the service life.

Special valve for oxygen pipeline

In the process of compressed transportation of oxygen in the oxygen pipeline, if there are grease, iron oxide shavings or small combustibles, a large amount of friction heat will be produced with the friction and collision between the air flow and the valve cavity, resulting in combustion and explosion. Therefore, the oxygen valve must carry out rigorous derusting, purging, degreasing and other treatment.

When the concentration of oxygen medium in the pipeline exceeds 23.5%, it can be judged as oxygen condition.

Production points of oxygen special valve:

1. The inner cavity of the oxygen valve should be smooth and smooth, and there should be no residual solid impurities.

2. The inner cavity and parts of the valve body have no edges, no sharp corners, no burrs, and all are arc transitions.

3. The valve must be strictly cleaned, degreased and tested by ultraviolet ray before assembly.

4. The high pressure gas is used to test the sealing performance of the oxygen valve.

5. After the valve inspection is qualified, the passage should be blocked, and then fully sealed packaging should be carried out to prevent oil and impurities from entering the valve cavity.