Previously, we discussed some issues and the basic situation of the calcium carbonate industry. Now, in response to the problems of extensive utilization, low-quality usage, and the shortage of the industrial chain in the domestic calcium carbonate resource utilization, we propose some development strategies and suggestions. The basic approach includes five aspects: mine integration, green mining, the principle of tiered utilization, optimized allocation, and coordinated development of industrial parks. This provides a systematic and detailed description of the methods and principles for the tiered high-value and efficient utilization of the calcium carbonate industry, offering important support for the establishment of targeted specific principles and policies for the high-quality and efficient utilization of mineral resources in our country.

1. Promote the regional integration of limestone mines.

Integrating mineral resources is an important means to concentrate on solving the unreasonable layout of mine development, achieving large-scale and intensive development of resources. It is a fundamental task to effectively govern the chaotic order of the mining industry from the source, and an effective way to adjust the mining structure and promote the transformation of the mining economic growth model. It has significant implications for building a resource-saving and environmentally friendly society and pursuing a new type of industrialization. To achieve high-value and efficient healthy development of the calcium carbonate industry, it is essential to first integrate limestone mines, unify management, unify mining, optimize allocation, and prevent the low utilization of high-quality minerals, which leads to the waste of high-quality limestone resources. Based on the author's years of experience in planning the calcium carbonate industry, the following three points should be addressed to achieve regional integration of mines.

(1) Promote geological exploration to increase and clarify the reserves and grade distribution of limestone resources. Due to historical reasons, most of the limestone resources in our country lack detailed data on the distribution of reserves, varieties, grades, occurrence, fractures, and the development of ore bodies. The true reserves, varieties, grades, and internal structures of the ore bodies are not fully understood, making it impossible to formulate scientific and accurate mining plans, which greatly restricts the unified intelligent green mining, optimized allocation, and tiered high-value and efficient development and utilization of limestone resources. Therefore, comprehensive geological exploration of mineral resources should be carried out within the regional scope to grasp detailed information on limestone resource reserves, grades, and distribution, providing sufficient resource reserves for the subsequent development of the calcium carbonate industry. Under the guidance of relevant national, provincial, and municipal policies, efforts should be made to actively seek national, provincial, and municipal funding for mineral resource surveys, comprehensively carry out surveys and exploration of mineral resources at the county level, and encourage public mineral resource surveys and exploration.

(2) Establish a state-owned holding mineral investment company to carry out unified mining, unified optimized allocation, and unified management of mineral resources. This platform should attract large high-end mineral mining enterprises, legally integrate mining rights within the mining area for compensation, and increase resource reserves, especially for high-quality limestone resources with large reserves and high grades. Eliminate small quarries that do not meet environmental protection, mining scale, mining technology, processes, and equipment standards.

(3) Deepen the integration of limestone mineral resources and the construction of green mining demonstration zones. To promote the high-quality and healthy development of the calcium carbonate industry and achieve unified management, unified mining, and optimized allocation of calcium carbonate resources, it is necessary to deepen the integration of limestone mineral resources and the construction of green mining demonstration zones. The integration process requires the following points:

① Establish a system for the cancellation or recovery compensation of mining rights. Efficiently integrate all limestone resources within the mining area, unify management, and for enterprises that already have mining rights within the mining area, the government should lead negotiations for compensation with the rights holders or cancel the mining rights of relevant enterprises, reclaim the mining rights while retaining the corresponding rights of the original rights holders, ensuring the integrity of mining rights within the mining area.

② Formulate principles for tiered optimized allocation of limestone resources based on demand. The mining work of limestone resources within the mining area should follow the principles of unified management, unified mining, and demand-based optimized allocation. The mining party should optimize allocation based on resource grades and the scale and product structure of calcium carbonate deep processing enterprises within the county, giving priority to production enterprises related to economic structural transformation or high-quality product development in the region. At the same time, retain part of the resource reserves to meet the needs of subsequent new industrial construction, maximizing the service of resources to enterprises and economic development.

③ Establish land compensation standards for mining areas. Government functional departments are responsible for communicating and negotiating with the public, adjusting the land nature within the mining area, and compensating for the relocation of existing buildings according to national and local government regulations, ensuring that there are no residents or farmland within the mining area.

2. Improve green mining of limestone mines.

Limestone mining enterprises must establish a scientific development concept, implementing green mining throughout the entire mining production process, from exploration, planning, construction, mining, processing, to mine closure, land reclamation, and ecological restoration. They should adopt advanced technology and equipment, implement strict intelligent scientific management, achieve fully rational development and utilization of resources, protect the environment, ensure safe production, and promote sustainable development of the mining economy, transforming the enterprise into a modern enterprise that faithfully fulfills social responsibilities.

(1) Standardized mining.

According to DZ/T0318-2018 "Standards for the Construction of Green Mines for Cement Limestone" and GB16423-2006 "Safety Regulations for Metal and Non-metal Mines", follow the principles of green mining and implement the policy of "simultaneous mining and stripping, stripping first, and mixed mining of rich and poor" to design a green mining plan for limestone mines.

① Limestone mining should strictly follow the development and utilization plan and design for mining, using a combination of top-down horizontal step mining and layered mining methods, controlling the height of mining steps and layers to not exceed 15m, and mining should strictly follow the requirements of "mining while managing".

② When mining reaches the final slope, controlled blasting measures such as pre-splitting or smooth blasting must be used to ensure the stability and integrity of the final slope, laying a good foundation for the subsequent "mining while managing and greening".

③ By improving blasting technology, adjusting the advancement direction of the working face, and avoiding corner ore loss, ensure that the mining recovery rate is not less than 96.5%.

(2) Advanced mining technology and equipment.

In terms of mining technology and equipment, enterprises constructing green mines should prioritize the use of efficient mining technologies and equipment that generate minimal waste and have a low impact on the ecological environment of the mining area. It is required to adopt internationally advanced drilling-blasting-loading-transportation mining technology, introduce currently advanced high-pressure integrated down-the-hole drilling rigs to replace ordinary down-the-hole drilling rigs, and use standardized mining-specific dump trucks to improve mining production efficiency, utilizing both domestic and foreign advanced equipment.

3. Establish principles for tiered high-value and efficient utilization of limestone resources.

Establish and improve the principles for tiered high-value and efficient utilization of limestone resources. The core is to closely follow the national opinions on the conservation and efficient utilization of mineral resources, adhere to existing national/industry standards and specifications for limestone resource utilization, and further establish and improve the standard specification system for high-value and efficient utilization of limestone resources based on the specific situation of current industrial development.

For the mining and utilization of limestone resources, the existing standards mainly refer to the DZ/T 0213-2002 "Geological Exploration Specifications for Metallurgical and Chemical Limestone and Dolomite, Cement Raw Material Mines" issued by the Ministry of Land and Resources, which stipulates the requirements for limestone used in industries such as cement, black metallurgy flux limestone, and non-ferrous metallurgy solvent limestone.

When the CaO% in limestone is ≥48% and MgO% <3%, it can meet the requirements for Grade I cement-grade limestone raw materials. When the CaO% in limestone ore is <45% and MgO% <3.5%, it can meet the requirements for Grade II cement-grade limestone raw materials. When the industrial grade limestone has CaO% ≥50% and boundary grade CaO% ≥48%, it can meet the requirements for black metallurgy solvent limestone; when the industrial grade limestone has CaO% ≥53% and boundary grade CaO% ≥50%, it can meet the requirements for non-ferrous metallurgy solvent limestone. At the same time, based on the experience of experts and relevant enterprises, the production of light (nano) calcium carbonate requires limestone resources as shown in Table 4, which requires that the limestone ore raw material has CaO% ≥54% and MgO% ≤0.7%.

However, the above standards only specify the minimum requirements for the grade of limestone used in various industries and related products, without specific requirements for the upper limit of grade, which greatly hinders the promotion of high-value and efficient utilization of limestone resources. Currently, in the context of mining development in China, once mining rights are granted, enterprises have legal rights to the mining, utilization, benefits, and management of mineral resources during the mining activities. However, enterprises generally produce a single product, and various grades of limestone resources are used for the production of one or two products, leading to a large amount of high-quality limestone resources being used for the production of low-value products with high market demand and low process and investment thresholds, especially in the construction sand and cement industries. Construction sand and gravel mostly focus on their mechanical properties, neglecting the ore grade requirements, and due to their small investment, large demand, and quick returns, a large amount of high-quality limestone can be processed into sand and gravel aggregates through simple processes such as crushing, shaping, and screening, which is one of the main ways limestone resources are consumed. According to data from the National Bureau of Statistics, in 2019, China's cement production exceeded 2.3 billion tons, with annual limestone consumption exceeding 2.8 billion tons. Currently, over 80% of the cement industry is controlled by central/state-owned enterprises and large private enterprises, which control over 90% of the mining rights to limestone resources, resulting in over 90% of limestone resources potentially being used for the production of low-value cement.

In response to the current situation of limestone resource mining and utilization in China, to achieve the tiered high-value and efficient utilization of limestone resources, it is necessary to realize the integration of mines and green mining. Based on existing national/industry standards and specifications for limestone resource utilization, combined with the specific situation of current industrial development and product technology processes, further establish and subdivide the upper limits of limestone grades required for each product, maximizing the value of high-grade limestone resources. The author, based on years of experience in the development and industrialization of calcium carbonate technology, processes, and equipment, has formulated a gradient change in CaO content in limestone, using high-quality limestone with a content greater than 54% to produce high-value-added light calcium carbonate and nano calcium carbonate products, mainly applied in high-end plastics, papermaking, coatings, pharmaceuticals, electronics, food, and other industries; using intermediate quality limestone with a content between 49% and 53% to produce active calcium oxide and the resulting calcium hydroxide, mainly applied in metallurgy solvents, chemical and food deep processing industries; and using low-quality limestone with a content less than 48% for the cement and construction industries. Based on the different CaO content in limestone resources, the limestone raw materials are tiered and allocated to relevant industries to ensure optimal resource utilization, maximizing value and environmental effects in a fully closed industrial chain.

4. Establishing an optimized allocation system for limestone resources

The optimized allocation system for limestone resources is a strong guarantee to prevent the low utilization of high-quality ores to the greatest extent, improve the utilization value of high-quality limestone resources, and accelerate the development of the calcium carbonate industry towards high quality. The optimized allocation of limestone resources must adhere to the following principles:

(1) Principle of product market demand. Based on the market demand for calcium carbonate products, reasonably set the production scale of enterprises and allocate calcium carbonate resource reserves.

(2) Principle of raw material grade supply based on product demand. Under the premise of meeting the raw material grade requirements and economic production of calcium carbonate products, delineate the corresponding grade range of calcium carbonate raw materials for the products to maximize the use of high-quality resources.

(3) Principle of product output allocation. Allocate the calcium carbonate resources needed for the production of products according to the output of the products produced by enterprises, avoiding a large amount of calcium carbonate resources being sold at low prices or used for the production of other low-end calcium carbonate products.

(4) Principle of regional economic allocation. Conduct regional economic allocation of calcium carbonate resources while fully considering factors such as regional mining and transportation costs.

5. Planning and development principles for calcium carbonate industrial parks

A reasonable layout of the calcium carbonate industrial park's industrial chain is especially important for the high-quality and healthy development of the calcium carbonate industry. Currently, calcium carbonate industrial parks in China generally face issues such as small enterprise scale, low-end products, low added value, outdated production processes and equipment, severe homogenization competition, and incomplete distribution and industrial chains, making it impossible to create calcium carbonate products with significant brand benefits. In response to the above issues in the development of calcium carbonate parks, the author believes that the "four development" principles must be adhered to.

(1) Chain development principle. Adhere to cultivating and improving the advantageous industrial chain as an important way for the development of calcium carbonate parks, build a mechanism for deepening the integrated development of the calcium carbonate industrial chain, and promote the establishment of mutual support and mutual promotion development patterns among enterprises and projects.

(2) Intensive development principle. Through concentrated layout of the calcium carbonate industry, promote the development of advantageous industries as the main focus, auxiliary industries supporting, and the closed-loop development of waste gas, waste residue, and wastewater disposal, effectively protect the environment, achieve resource conservation, comprehensive utilization, and recycling of calcium carbonate resources, and promote the transformation of the development model of the calcium carbonate industry.

(3) Cluster development principle. Focus on the main body of the calcium carbonate industry, support and establish leading enterprises that are the "core" of the advantageous industrial chain, promote the formation of a competitive yet cooperative development trend in the calcium carbonate industry, enhance the ability to absorb, gather, and radiate industries outside the industrial park, and establish a development model that radiates the surrounding areas from a "point".

(4) Cooperative development principle. Insist on treating calcium carbonate industrial parks as platforms for cooperation and openness, actively undertake the transfer of high-quality related industries in key areas. Based on regional industrial and economic cooperation within the province, support the establishment of related industrial parks across regions, and explore new models and operational management mechanisms for the construction of calcium carbonate industrial parks.

Summary:

With the proposal of high-quality and healthy development of our country's economy, the demand for high-end calcium carbonate products in industries such as plastics, rubber, coatings, and papermaking will increase sharply. For a long time to come, the calcium carbonate industry has a strong development prospect. However, since 2019, the global economy has shown a slowdown in growth, and the homogenization of global technology and products has led to intense competition in the global market. The core technology and equipment of the high-end calcium carbonate industry are subject to stricter foreign restrictions, which poses new challenges for enterprises that require high-end calcium carbonate products. However, this also provides opportunities for our country's high-end calcium carbonate product industry. The development of domestic high-grade nano calcium carbonate, ultrafine calcium carbonate, medical-grade, and food-grade calcium carbonate products will surely accelerate; at the same time, functional and specialized calcium carbonate products will also be the direction of future development. Additionally, the development of new surfactants to improve the properties of calcium carbonate powders is also a pressing issue that the calcium carbonate industry needs to tackle.

While grasping the main development directions of the calcium carbonate industry mentioned above, it is also important to pay attention to the harmonious scientific unity of the natural, social, and environmental attributes of calcium carbonate industry resources. We must treat resources well from the beginning of the calcium carbonate industry chain, adhere to green mining, intensive utilization, optimized allocation, and tiered utilization; the production processes and equipment of calcium carbonate products in the chain should be green, intelligent, and large-scale; and the end of the chain should focus on refinement, specialization, functionalization, and serialization. At the same time, we should increase government guidance and support, strengthen the strong alliances between enterprises and between enterprises and research institutions, fully leverage advantages, and believe that the future development of our country's calcium carbonate industry is promising.