Is the "slag hill" beside the Yangtze River solid waste or raw jade
——Investigation of phosphogypsum storage pollution and comprehensive utilization
Our reporter Li Jing, China Building Materials News reporter Liu Fangfang
With the rapid increase in my country's phosphate fertilizer production, the by-product phosphogypsum stockpiles continue to expand.
If long-term stockpile management is not in place, these "slag hills" will become pollution sources.
On the one hand, there is the production of phosphate fertilizer and the continuous mass production of phosphogypsum, which affects food security, on the other, the pollution caused by irregular stockpiling and the ever-decreasing stockpiled land. How can this contradiction be broken?
The reporter found in the investigation and interview that people in the industry generally believe that it is still necessary to work hard to solve the problem.
In recent years, a large-scale remediation operation is being carried out in the Yangtze River Basin, and the focus of the remediation is the phosphogypsum storage (storage yard) on the edge of the Yangtze River.
In Jingmen, Hubei, the reporter saw that the once gray "slag mountain" was re-covered in green after "seepage prevention, flood interception, pollution interception, prevention of scattering, and groundwater monitoring"; in Hongdaluo, Shifang, Sichuan After the hydrophosphogypsum storage yard has undergone measures such as reinforcement, seepage prevention and greening, the black-gray “hills” that used to be several kilometers long and ten meters high have now become lush mountain views in front of reporters.
What is a phosphogypsum bank?
Why is the renovation of the phosphogypsum reservoirs in the Yangtze River Basin a priority for many provinces and cities?
What harm does the long-term storage and management of the phosphogypsum reservoir have to the ecological environment?
Can all these phosphogypsum "mountains" be removed?
Many environmental pollution problems
"The phosphogypsum storehouse refers to a place where dams are built or where various terrains are used to store phosphogypsum, and phosphogypsum is an industrial by-product produced during the preparation of phosphate fertilizers." Ye Xuedong, a senior engineer from China Phosphate Compound Fertilizer Industry Association, told reporters.
Specifically, phosphogypsum is a by-product in the process of decomposing phosphate rock and extracting phosphoric acid by sulfuric acid, and phosphoric acid is the main raw material for preparing phosphate fertilizer.
In 2005, my country's phosphate fertilizer output surpassed the United States to rank first in the world, ending the long history of importing phosphate fertilizers, and increasing crop production is guaranteed.
However, with the rapid increase in phosphate fertilizer production, a large amount of phosphogypsum has been produced.
At that time, the path for bulk use of phosphogypsum had not yet been formed, and it could only be stored or landfilled.
"The production of 1 ton of phosphoric acid produces about 5 tons of phosphogypsum. At present, the stock of phosphogypsum in my country exceeds 600 million tons, and the annual output is 75 million tons." said Zou Jiefu, chief engineer of China Energy Conservation and Environmental Protection Group.
Because most of my country's phosphate fertilizer companies are concentrated in the Yangtze River Basin, the problem of phosphogypsum storage, which is one of the pollution problems of the Yangtze River "three phosphorus" (phosphate rock, phosphorus chemical industry, and phosphogypsum reservoir), has emerged.
According to data released by the Ministry of Ecology and Environment, there are a total of 97 phosphogypsum reservoirs in 7 provinces and cities in the Yangtze River Basin, of which 53.61% of the phosphogypsum reservoirs have caused environmental problems due to poor management and irregular storage.
"Although phosphorus plays an indispensable role in the growth of plants, phosphogypsum contains a large amount of phosphorus and fluorine impurities. If the phosphogypsum is not properly filled, it will cause serious pollution." Secretary of the China Building Materials Federation Gypsum Building Materials Branch Chang Yang Zaiyin told the Economic Daily reporter that in the first half of 2018, statistics showed that in the nationally controlled sections of the Yangtze River Economic Belt, 56% of the sections with excessive total phosphorus indicators accounted for 56% of all sections, and total phosphorus has become the primary pollutant of the Yangtze River.
It is worth noting that the phosphogypsum landfill problem not only occurs in the Yangtze River basin, but also exists in southwestern provinces such as Yunnan and Guizhou.
For example, Yunnan Province has formulated a timetable for the renovation of 8 phosphogypsum reservoirs in the region, requiring that the leachate of the phosphogypsum reservoirs be effectively collected and treated by the end of this year, and none of them will be discharged.
What are the consequences of phosphogypsum pollution?
Yang Zaiyin pointed to a bag of phosphogypsum samples and told reporters: “Generally speaking, the main impurity elements in phosphogypsum are phosphorus and fluorine. Especially in closed or semi-enclosed lakes and river bays, soaring phosphorus content will cause water bodies. Eutrophication has led to rapid growth of algae plants, a sharp decline in the oxygen content of the water body, and the death of fish and shellfish and other aquatic animals due to hypoxia." If the storage is not properly managed, the soluble fluorine in the phosphogypsum will flow into the water and the soil. Excessive intake of food and drinking water can seriously affect your health.
"In fact, reasonable and standardized storage will not cause excessive pollution. The key is whether it meets the storage specifications." Ye Xuedong told reporters that the engineering construction management of the phosphogypsum storage yard is very strict, and the related engineering construction and design must comply with the ten Several standards and regulations.
But in the eyes of industry enterprises, even standardizing stockpiling is only a "stoppable measure."
"Heap, can't solve the fundamental problem." A person in charge of a phosphate fertilizer company told reporters that the phosphogypsum library has a service life of about 10 years in accordance with the design standards and regulations.
Calculated by time, there will be phosphogypsum reservoirs in the Yangtze River Basin that have reached their useful life in the past year and must be "closed". At the same time, the "fixed production with slag" and tightening land policies in some areas are reducing the accumulation of phosphogypsum. Save space.
On the one hand, there is the production of phosphate fertilizer and the continuous mass production of phosphogypsum, which affects food security, on the other, the pollution caused by irregular stockpiling and the ever-decreasing stockpiled land. How can this contradiction be broken?
In addition to regulating storage, is there a better way out for phosphogypsum?
The answer of many people in the industry is "Yes."
Phosphogypsum is regarded as a solid waste and pollution source in the eyes of ordinary people, but in the eyes of professionals, it is "unprecious jade".
Initial results of comprehensive utilization
"In terms of industry classification, phosphogypsum belongs to industrial by-product gypsum. At present, 80% of the raw materials used in gypsum building materials come from industrial by-product gypsum." Yang Zaiyin told reporters that phosphogypsum can become a high-quality gypsum cementing material through purification and washing. The raw materials have the characteristics of heat insulation and sound insulation, high construction efficiency, environmental protection and health, etc., and can be widely used in many fields such as building materials, chemicals, molds, etc.
In the construction and decoration market, gypsum board, gypsum mortar, blocks, slats and gypsum mold boxes produced with phosphogypsum as raw materials have become competitive building materials products.
"In the statistics of 2019, cement retarders, gypsum board, plastering plaster, mold gypsum, etc. have become the key areas for phosphogypsum consumption." Yang Zaiyin opened the computer and pointed to the consumption of phosphogypsum in 2019. Statistics told reporters: "In 2019, cement retarders will absorb about 10.5 million tons of phosphogypsum, and paper-faced gypsum boards will absorb about 3.5 million tons of phosphogypsum. The building materials industry is the largest export of phosphogypsum."
Enterprises act early.
In April 2014, Taishan Gypsum (Xiangyang) Co., Ltd., a subsidiary of China National Building Materials Group, was inaugurated in Baokang Industrial Park, Yujiahu, Xiangyang, Hubei.
The person in charge of the company told reporters that, as an industrial by-product gypsum comprehensive utilization enterprise, 70% of the raw materials used in the company's products are phosphogypsum.
The gypsum board produced through a series of technological processes has strong market competitiveness and can consume nearly 300,000 tons of phosphogypsum every year.
In Guizhou, Guizhou Phosphate (Group) Co., Ltd. uses a new gypsum green building material production, supply and marketing system to absorb phosphogypsum. In 2019, it achieved more than 6.5 million tons of phosphogypsum. Paper-faced gypsum board, gypsum mortar, block, The comprehensive utilization capacity of phosphogypsum, such as slats and gypsum mold boxes, to meet market demand can handle more than 3 million tons of phosphogypsum. The company also uses phosphogypsum in large quantities in cement retarders and other fields.
Industry enterprises are working hard, and policy promotion is also essential.
As early as 2011, the Ministry of Industry and Information Technology issued the "Guiding Opinions on the Comprehensive Utilization of Industrial By-product Gypsum", which pointed out the development direction of resource utilization and comprehensive utilization of industrial by-product gypsum including phosphogypsum.
In 2015, the "Guiding Opinions on Promoting the Transformation and Development of the Chemical Fertilizer Industry" issued by the Ministry of Industry and Information Technology proposed to vigorously develop new fertilizers and improve the development and utilization of phosphogypsum.
Not only that, in 2015, the "Resource Comprehensive Utilization Products and Labor Services VAT Preferential Catalogue" issued by the Ministry of Finance and the State Administration of Taxation gave a 70% VAT refund policy to taxpayers and enterprises selling products using waste residues such as phosphogypsum as raw materials.
On October 24, 2019, the Ministry of Finance and the State Administration of Taxation jointly issued the "Announcement on the Value-Added Tax Policy for the Comprehensive Utilization of Resources", combining cement additives, construction gypsum, α-type high-strength gypsum, type II anhydrous gypsum and other phosphogypsum comprehensive utilization products Included in the category of preferential policies that enjoy 70% VAT refund upon collection.
With the continuous exploration of enterprises and the active promotion of policies, the comprehensive utilization of phosphogypsum in my country has achieved initial results.
According to data from the Gypsum Building Materials Branch of the China Building Materials Federation, as of 2019, the comprehensive utilization rate of phosphogypsum in my country has increased by about 20% compared with 2009, and the comprehensive utilization rate has increased to 40%.
However, in the face of 600 million tons of stockpiles and 75 million tons of annual production, the annual use of phosphogypsum is currently only 31 million tons.
The speed of comprehensive utilization still "cannot catch up" with output.
The "stuck neck" problem remains to be solved
It has to be said that phosphogypsum is a very high-quality resource, and some industry experts believe that phosphogypsum is a strategic resource.
But even with many comprehensive utilization methods such as cement retarder, gypsum board and gypsum mortar, the comprehensive utilization of phosphogypsum still faces the problem of "stuck neck".
"The application of phosphogypsum is currently in a vicious circle." Tang Shaolin, chairman of Jiangsu Yifu Technology Co., Ltd., told reporters that the main problems are focused on the two ports of technology and market.
The comprehensive utilization of phosphogypsum is difficult, and the pretreatment is difficult.
Phosphogypsum has high impurity content and diversification, the pretreatment process is extremely complicated, and the cost is relatively high.
If handled with high standards, it will lead to high prices of finished products and weak market competitiveness; but if handled well, inferior products will damage the image of the industry.
"The market acceptance is not high, and companies are unwilling to continue to invest. Over time, comprehensive utilization will become nameless."
The reporter's research in some cities in the southwest confirmed Tang Shaolin's views.
In some places in Guizhou, "talk about phosphorous discoloration".
Because some manufacturers use phosphogypsum with high impurity content to produce building materials, and do not do moisture-proof treatment on the products, it causes quality problems in later use.
A sales person in charge of a building materials market in Guizhou told reporters that local consumers used phosphogypsum materials to decorate their houses, and the damp parts had mildew within two years.
"Consumers dare not use such building materials, and we dare not buy them again."
In addition to the cost problems caused by technical difficulties, logistics costs are also a bottleneck facing the development of enterprises.
The original Guizhou Kailin Group, which was incorporated into Guizhou Phosphate (Group) Co., Ltd. (hereinafter referred to as "Guizhou Phosphate Group") in 2019, encountered such a setback.
"In addition to underground filling in the original Kailin Group's treatment of phosphogypsum, the cement retarder is also the main digestion point for phosphogypsum. However, this road will soon fail." Guizhou Kailin Construction Group Co., Ltd., a subsidiary of Guizhou Phosphate Group People told reporters that phosphorous chemical companies are far away from cement bases. To continue to supply phosphogypsum to cement bases, it is necessary to subsidize transportation costs. Long-term subsidies make companies "unbearable", and the company also gave up phosphogypsum to prepare cement retarders. The comprehensive utilization of agents.
Xu Luoyi, chairman of the Gypsum Building Materials Branch of the China Building Materials Federation and director of the Institute of Building Materials Industry Technology Information, told reporters: "The phosphogypsum production areas are mainly distributed in Hubei, Yunnan, and Guizhou. The production areas are scattered and far away from the consumer market, and the transportation radius is long. A strange phenomenon was formed that the areas that are urgently needed cannot be bought, and the areas that are stockpiled cannot be used."
In addition, how to implement policies more effectively is also a problem encountered by many companies in the building materials industry.
Yang Zaiyin believes that the inconsistent understanding of the "Announcement on the Value-Added Tax Policy on Comprehensive Utilization of Resources" by the local tax authorities has had a considerable impact on the enthusiasm of building materials companies to promote the comprehensive utilization of phosphogypsum.
The "Announcement on the Value-Added Tax Policy for Comprehensive Utilization of Resources" proposes that "taxpayers sell self-produced phosphogypsum resource comprehensive utilization products". During the implementation, some local tax authorities understood "self-produced" as "only phosphate fertilizer that produces phosphogypsum" Only enterprises can enjoy the VAT refund policy, while other non-phosphate fertilizer companies, namely non-phosphogypsum emission companies, process phosphogypsum into the announcement's construction gypsum, α-type high-strength gypsum, type II anhydrous gypsum, and wallboard No products such as mortar and mortar can enjoy the 70% VAT refund policy."
Xu Luoyi believes that there are also policy imbalances between regions. In some regions, specific support projects and special subsidies are in place, and some local policies have not been implemented.
The lack of talents is also the main shortcoming restricting the comprehensive utilization of phosphogypsum.
Zheng Jianguo, deputy chief engineer of Henan Building Materials Research and Design Institute, told reporters that colleges and universities have integrated materials majors into "big materials" majors. As one of the cementing materials, gypsum does not have a corresponding gypsum major. There is usually only one chapter in college courses. , The knowledge learned is far from enough.
The key to removing the "Slag Mountain" is "use"
The industry has racked their brains for the comprehensive utilization of phosphogypsum, and the masses are most concerned about when the phosphogypsum "mountain" in the Yangtze River can be completely removed.
"The problem of the Yangtze River phosphogypsum reservoir must be divided into two." Yang Zaiyin said that in the short term, standardized storage and management can remedy the currently polluted phosphogypsum reservoir, but the complete removal of the phosphogypsum reservoir on the bank of the Yangtze River still requires Work hard on the word "use".
"The effective treatment of phosphogypsum is a worldwide problem. At present, it is faced with the problems of lack of talents, narrow channels, serious homogeneity, and high value-added utilization channels have not yet formed, but these problems are also the potential of phosphogypsum." Wuhan University of Technology Professor Yang Xinya said.
The data investigated by the reporter also corroborated Yang Xinya's views.
According to statistics, in 2019, the building area of construction enterprises nationwide was 4.024 billion square meters. The theoretical demand for gypsum series products using industrial by-product gypsum such as phosphogypsum as the cementing material is about 350 million tons, but the actual usage is less than 35 million tons. , Less than 10% of the overall demand, the market space has yet to be developed, the development potential is huge, the key is to solve the problem of market promotion and application.
"To solve the problem of market promotion, it is necessary to promote demonstration projects." Xu Luoyi believes that "In the process of promoting comprehensive utilization projects, the production of raw materials is often discussed, and there are fewer application problems." Xu Luoyi suggested that the project approval department should lead the relevant applicable projects to set an example.
In this regard, Tang Shaolin believes that phosphogypsum is not a single resource, product or industry, and involves a wide range of areas.
The comprehensive utilization of phosphogypsum must be promoted. On the one hand, it must be publicized and popularized so that consumers can understand this by-product gypsum product; on the other hand, it is necessary to increase investment from the source of phosphogypsum emissions to effectively eliminate the harmful substances of phosphogypsum. The "down-to-earth" industry model.
What Jiangsu Yifu has explored is "a laboratory economy model with the goal of digesting and utilizing industrial by-product gypsum, scientific research and development as the core, and a full range of professional technical services as the main body".
In this mode, a new phosphogypsum application technology was also born.
In the R&D center of YIFU company, R&D personnel showed reporters the high-temperature calcination technology of phosphogypsum.
"This can completely decompose the organic matter in phosphogypsum, and at the same time make phosphorus and other impurities generate insoluble inert substances. The produced type II anhydrous gypsum can replace cement for wall plastering and floor leveling." Jiangsu Yifu Technology Tang Yongbo, director of the R&D Center of the Co., Ltd., told reporters that Yifu has also developed a complete set of technology and equipment for the large-scale comprehensive utilization of industries such as the free water-to-crystal method for large-scale production of α-type high-strength gypsum production lines.
Tang Shaolin also has new ideas for solving the problem of talent shortage.
"We have established the National Engineering Technology Center for the Resource Utilization of Gypsum by-products of Environmental Protection Industry. The next step will be to rely on this center to unite industry-related universities and combine production, study, research and use to accelerate the training of talents in the gypsum field, and strive to explore a new technology. Cooperation, talent training model." Tang Shaolin said.
In Tang Shaolin's view, to make phosphogypsum "usable and easy to use", it is not only necessary to ensure the normal operation of the enterprise, but also to make the enterprise profitable and effective, so as to truly stimulate the vitality of the comprehensive utilization of phosphogypsum.