Liu Liwei: Zinc-rich VS Zinc, there is no need to waste zinc powder resources!

Liu Liwei Chairman 

Suzhou Greeful Nano Technology Co.

❖Media interview

E Zhongmin "Coating and Protection"

Biography

Liu Liwei, researcher and doctoral supervisor of the Suzhou Institute of Nanotechnology and Nanobionics, Chinese Academy of Sciences; Chairman of Suzhou Greifen Nanotechnology Co.

"Coating and Protection": History, technical development, and current market development status of epoxy zinc-rich coatings?

Epoxy zinc-rich coatings have been put into use in Europe in the 1940s.

In traditional epoxy zinc-rich coatings, in order to achieve good metal anti-corrosion performance, a large amount of zinc powder is required to form an electrochemical conductive path, and the amount of metal zinc in the non-volatile content is required to be as high as 60% to 80% (HG/T3668-2009).

However, the massive use of zinc powder resources is only a technical limitation and not necessary

For more than 80 years, traditional epoxy zinc-rich coatings have hardly made major technological breakthroughs, and technological stagnation has also led to serious product homogeneity competition.

With the emergence of new innovative graphene zinc powder coating products with excellent performance, high cost performance, low carbon and resource saving social value, driven by innovative companies, they will gradually penetrate the epoxy zinc-rich market and achieve Substitution and upgrading of products and markets

"Coating and Protection": The resources and use of zinc are worrying.
What impact will it have on the zinc-rich coating and galvanizing industry?

Zinc reserves are limited on the earth, which is a depleted resource, and half of the total consumption is used for metal anticorrosion
.
According to the United States Geological Survey (USGS) in 2021, the world’s proven zinc reserves are 250 million tons, Australia accounted for 27% of the total, and China accounted for 17%
.
In 2020, the global zinc mine output will be 12 million tons
.

In 2020, China's zinc production will be 4.
2 million tons, accounting for more than 34% of the world's total, and the proportion of production will be higher than that of reserves, making China the world's largest zinc consumer
.
While China’s zinc mine reserves are 44 million tons, China’s static mining life (current reserves/current production) does not exceed 10 years
.

Metal zinc reserves are limited.
If it cannot be effectively controlled and used excessively, it will affect the life cycle of all anti-corrosion coatings that use zinc powder, such as hot-dip galvanizing, epoxy zinc-rich, inorganic zinc-rich, cold-coated zinc, and even heavy-duty anti-corrosion coatings.
Sustainable development of the industry
.

"Coating and Protection": Under the framework of the goal of "carbon peak and carbon neutrality", what is the production status and market trend of zinc?

According to preliminary statistics, in 2020, China's total non-ferrous metal carbon dioxide emissions will be about 650 million tons, accounting for 6.
5% of the country's total emissions
.
Zinc ranks third in carbon emissions per ton of metal production, with aluminum>nickel>zinc
.

80% of the primary zinc ingots are produced by wet smelting.
The smelting production of zinc consumes up to 4000 kWh per ton of zinc, and the carbon emissions are about 5.
19 tons
.
The production of fine zinc powder for coating applications needs to be heated to a high temperature of about thousands of degrees.
To produce 1 ton of zinc powder, the electricity consumption is about 1000 degrees (kW/h)
.
Metal zinc smelting and zinc powder production are both energy-intensive, and both face the pressure of dual control of energy consumption and dual carbon targets
.

Recently, the price of zinc has broken through the rise.
In the short term, domestic and foreign energy and power supply are tight, and the long-term bullish trend is due to limited zinc powder resources and pressure to reduce carbon emissions
.
As the "Lead and Zinc Industry Specification Conditions (2020 Edition)" tightens the industry's environmental protection, energy consumption, and technical requirements, as well as regulates disorderly mining, the degree of external dependence increases, and the production cost of metallic zinc will maintain an upward trend
.

"Coating and Protection": The resource problem of zinc has become increasingly prominent, and the coating industry is also committed to the technological innovation of graphene low-zinc coatings.
What are the results in recent years?

Nowadays, China's leading graphene zinc powder coating technology and industry standard (HG/T 5573-2019), through the integration of graphene innovative technology, graphene replaces a large amount of zinc powder to form a conductive path, and provides good shielding for zinc powder and metal Protection
.
Among them, the amount of dry film metal zinc can be reduced to 30%
.

The optimized formulation of graphene zinc powder coating uses a small amount of high-quality thin-layer graphene, only 30% of the non-volatile content of metallic zinc, and the resistance to neutral salt spray can be as high as 3000~6000 h (single coating, scratch Marks, within 90 μm film thickness), the salt spray resistance time exceeds 3 times the C5 environmental requirement defined by ISO12944, and exceeds the "graphene zinc powder coating" (HG/T 5573-2019), "zinc-rich primer" (HG/ T 3668-2009) more than 3 times the standard
.

In addition to improving the salt spray resistance, it also improves the convenience of construction.
The reasonable use of high-quality graphene also has very good thick film resistance to cracking, increasing the toughness of the paint film, and improving the adhesion of the paint film to the substrate substrate.

.

The innovative technology of new graphene materials will have a profound impact on the coatings industry.
High-quality graphene zinc powder coatings.
In order to save zinc, reduce carbon and reduce costs, the development of graphene zinc powder coatings is the realization of the sustainable development of the zinc coating industry.
Important safeguards
.

In the traditional concept of zinc powder dosage, "zinc-rich" means good anti-corrosion performance, and "low zinc" means "cut corners".
With the advent of graphene zinc-containing coatings, these understandings can be changed
.
Graphene and a small amount of zinc powder are used to achieve excellent anti-corrosion performance.
The anti-corrosion performance is not proportional to the amount of zinc powder
.
There is no need to waste zinc powder in the future .

"Coating and Protection": From the perspective of saving zinc powder resources and material costs, what is the prospect of graphene innovation in the market for the replacement and upgrading of zinc-rich anticorrosive coatings?

High-performance graphene zinc powder coatings.
Under the guidance of policies and standards, with the participation and promotion of many research institutes and innovative companies in the industry, a new graphene zinc powder coating track has been formed and has begun to gradually develop vigorously.
The promotion of industry standards has gradually begun to promote enterprises and markets
.

By saving zinc powder resources, reducing the cost of epoxy zinc powder coatings, and reducing the zinc powder by more than half, it is equivalent to saving about 25% of material costs.
The use of high-quality graphene innovative technology can greatly increase the added value of products
.

In addition, the high-performance graphene zinc powder coating can reduce maintenance, extend the service life, and save resources and costs
.
In particular, the protection period of the main body coating of the bridge in the newly revised version of JT/T 722 has been increased to 30 years (except for the attached steel structure)
.

At present, the application of graphene anticorrosive coatings in bridges, petrochemicals, energy, wind power, marine engineering, construction steel structures and other markets is gradually expanding, and it has become an inevitable trend to replace traditional epoxy zinc-rich products that are in the decline of product life
.

From the perspective of technological development, upgrading and substitution, cost performance, energy saving and carbon reduction, and resource saving, there is no need to waste zinc powder resources
.

Graphene innovative technology saves zinc powder resources, reduces energy consumption and carbon emissions, conforms to the national "dual carbon" goal and related industrial policies, and also conforms to the development trend of the coating industry toward green and resource conservation.
At the same time, it improves protection performance and extends Protection time, reduce material costs and maintenance costs
.
New technologies will change the market structure of industrial anti-corrosion coatings in the future and help the industry to develop with high quality
.