Low-grade vanadium-titanium magnetite develops circular economy

Sichuan Yiyi County Anning Iron and Titanium Co., Ltd. is an integrated private enterprise that comprehensively utilizes the Pangxi Panjiatian vanadium- titanium magnetite resources. The existing assets are 260 million yuan, and an annual output of 1 million tons of iron concentrate has been formed. The production scale of titanium concentrate of 200,000 tons, the current generation of solid waste - about 1.5 million tons of tailings. In recent years, in order to alleviate the contradiction of resource constraints, the company has invested more than 250 million yuan to carry out technical transformation of the entire production process, so that the raw ore selected grade will be reduced from TFe32% to TFe18%-20%, and the production wastewater will be recycled after treatment and disposed of properly. The tailings pond realized zero emissions, and initially formed a new industrialization pattern characterized by resource conservation and clean production. The company has entered the “Top 50 Enterprises in Panzhihua City” for three consecutive years and won the honors of “Advanced Unit of Environmental Protection in Panzhihua City” and “Little Giant Enterprise in Sichuan Province”.

Different from many large enterprises such as Panzhihua Iron & Steel Co., Ltd., the company originally used low-grade vanadium-titanium magnetite resources. The comprehensive geological grade of mine ore is only TFe24%, and the grade is 18%~24% of TFe. Off-balance-sheet super-poor resources are widely distributed and have a large number, accounting for about 50% of the total reserves. The comprehensive utilization of this part of the ultra-poor low-grade vanadium-titanium magnetite is not only critical to the company's sustainable development, but also to the comprehensive utilization of the Titan resources in the Panxi mining area, especially the Hongge mining area. It also plays an important role in promoting and promoting. In the comprehensive utilization of low-grade vanadium-titanium magnetite in Miyi County, after years of production practice and exploration, a unique process has been gradually formed: the original ore is pre-discarded, and the poor ore resources are comprehensively utilized; The factory takes the water mountain from Anning River, rough processing the original ore, and the pipeline is transported from a long distance to the mountain; the third stage is selected by iron; the two sections are combined with dry magnetic separation to select titanium; the strong magnetic flotation is used to recover the titanium in the tailings. Zero tailings discharge, comprehensive dust control, recycled water recycling; iron concentrate, titanium concentrate product quality has great advantages.

First, reduce the grade of raw ore selected, improve the comprehensive utilization of resources

The initial production scale of the company is 100,000 t/year for iron concentrate and less than 20,000 t/year for titanium concentrate. The mining and ore dressing process is relatively backward. It can only be produced by using TFE32% of ore tissue, while TFe is 18% to 24% of ore. Basically, it is stripped with the soil and becomes an abandoned ore-bearing surrounding rock, which causes a large waste of resources and at the same time increases the pressure on the mine dump. In order to change the waste of serious resources such as “taking rich and abandoning poverty, mining and abandoning difficulties”, and realizing the recycling of waste, the original ore of about 20% of TFE, which was originally stripped with soil, was used. The company hired many experts in geology, blasting and mining. And repeated research and experiments with some domestic scientific research institutions, developed a medium-hole surface network blasting and step-by-step mining plan from top to bottom; newly purchased multiple large excavators and loaders, replacing manual mining with mechanical operations, achieving scale The purpose of mining. At the same time, the magnetic separation drum machine is used in the mine to dispose of the low-grade ore, so that the waste ore with too low TFe ≤ 10% in the ore does not enter the ball milling system, successfully solving the negative impact of magnetic agglomeration on grinding and grading. To achieve the comprehensive utilization of the original ore of about 20% of TFe, and to avoid the influence of ballast surrounding rock in the low-grade ore to affect the efficiency of the ball mill . The success of this process transformation has a decisive role in achieving good economic and technical indicators for low-grade ore processing.

Second, reform the production process, implement process reengineering, reduce energy consumption

Comprehensive utilization of low-grade vanadium-titanium magnetite has increased the company's raw ore processing capacity from 500,000 t/year to 4 million t/year. If the car is used to transport the ore from the mine to the mountain, it is vulnerable to mining roads. Factors such as capacity, car, rainy season, solid waste, etc., also consume a lot of energy. In order to achieve large-scale production and save energy, it was decided to grind the front section of the step grinding process, and set it at a distance of 2km from the mine to rough the ore. Two new pipelines will be built, one will take the water mountain from Anning River to meet the production needs; the other will transport the original slurry down the mountain to replace the automobile transportation.

The height difference between the company's mine and Anning River is 760m, and the distance from the plant is 15km. The slope of the mine road is more curved and the terrain is complex. If the river is successfully transported to the mine, the ore will be transported down the mountain smoothly. This is a weak technical force at that time. For private enterprises, the difficulty can be imagined. However, the company did not retreat in the face of difficulties. Under the leadership of the general manager of the company, the company organized relevant experts and management personnel to design the production process and process, the selection of equipment and materials, the arrangement and orientation of the pipeline, the selection of slope and camber, and the flow rate. , flow rate, concentration and particle size control, lift, pressure considerations and many other technical links, repeated repeated argumentation studies, decided to use the three-stage pressure method to transport the Anning River water to the high-level pool of the 760m high mine selection plant, and Reasonably use the height difference to arrange 12km steel-rubber composite pipeline along the highway, so that the original slurry will flow down the mountain. The way the more traditional way of ore cars to save energy standard coal of about 6700t / year.

Third, optimize the step-by-step selection process to improve the efficiency of iron selection

For the beneficiation operation of vanadium-titanium magnetite, the domestic two-stage grinding step selection process is basically adopted. The advantage of this process is that the iron selection effect is good, but due to the coarse grain size of the iron ore tailings, it is not conducive to re-election of titanium. Lead to low recovery of titanium.

How to efficiently select iron and efficiently select titanium and reduce the content of titanium resources in tailings? The company's original three-stage grinding order selection mode has solved this problem well. A section of grinding, grading and magnetic separation concentrate is used as raw material to enter the second-stage grinding; the second-stage grinding, grading and magnetic separation concentrates are used as raw materials to enter the third-stage grinding; the third-stage grinding is closed-circuit screening, Grinding, magnetic separation, magnetic dehydration to obtain high-quality iron concentrate products; the first, second and third stage after the magnetic separation of the tailings, all concentrated into the titanium selection process. The production process is the first in China. After years of practice, it has been proved that the comprehensive effect of iron and titanium recovery is good, the iron recovery rate is high (the recovery rate of iron ore to the original ore TFE is above 55%), the product quality is stable, and the economic and technical indicators good.

Fourth, the combination of spiral and dry magnetic separation to improve the recovery rate of titanium

Domestic vanadium-titanium magnet ore dressing enterprises use the shaker to select titanium or strong magnetic flotation method for the recovery of TiO ₂ from iron ore tailings. The disadvantage of this method is that the water consumption is large, the recovery rate of TiO _{2 is} low, and the cost is too high.

In order to improve the recovery rate of titanium and reduce the cost of mineral processing, the company explored a unique sorting process for re-elizing titanium from iron ore tailings through years of exploration and practice, that is, the iron tailings were concentrated by a swirler. The second selection of spiral chute produces titanium semi-finished ore and tailings. After removing iron from titanium semi-finished ore, it enters dry magnetic separation by drying, cooling, sand blasting and dry selection to produce qualified titanium concentrate, spiral tailings and low grade. Dry-selected tailings all enter the flotation system. The production practice proves that the quality of the process is stable and the recovery rate of titanium is high (the recovery rate of titanium concentrate to TiO ₂ of iron ore tailings is above 25%), and the production cost is low.

Fifth, increase the strong magnetic flotation, tailings re-selection of titanium recovery

How to minimize the titanium in the tailings and further recover the titanium has always been an important topic in the research of titanium and titanium magnets.

In order to maximize the potential of titanium, the company took the lead in the use of high-gradient magnetic separators for the strong magnetic recovery flotation of titanium. The first phase of the project has been completed and put into operation. The annual increase of titanium concentrate is 1.5 to 2 million tons. The iron grade in the final tailings is reduced from 14.5% to 13.5%, and the grade of titanium is reduced from 8% to 7%. The second phase of the project is scheduled to be completed in 2008. The final tailings iron grade will fall below 13%, the titanium grade will fall below 5%, and the titanium concentrate production will increase by 50,000 t/year.

Sixth, energy saving and emission reduction have achieved results and achieved “zero emissions”

The company self-financing 33.7 million yuan, were 9.13 million m ³ of tailings library off-site expansion. The construction of the tailings pond not only makes the solid waste-tailing piles piled up in an orderly manner, but also makes the production wastewater settle in the high-level pool of the company after it has been cleared in the warehouse, and re-enters the production process for recycling, which can save every year. Take 3.3 million tons of water. Now the company has successively invested funds, completed the pollution source control of the railway station yard, the dust control of the titanium-selecting workshop, technically reformed the tail water storage pipeline and the production workshop wastewater, and recovered the tail water to 800m ³ /h, saving 6.33 million water. m ³ / year, reached the company's energy-saving emission reduction targets, and basically achieved "clean production, zero emissions."

7. The circular economy is well built and the quality of the products is on the rise.

After the implementation of the technical transformation, the iron concentrate and titanium concentrate not only have a large increase in production capacity, but also a qualitative leap in product quality. Iron concentrate products have the unique advantages of low iron and high titanium, TFe 55% ~ 60%, TiO ₂ <10%, S, P double zero, -200 mesh particle size ≥ 60%, praised by major steel mills. Titanium concentrate products have the characteristics of stable quality TiO ₂ =47%±0.5%, high iron content low Fe ₂ O ₃ ≤7.0%, S and P double zero, which are very popular among users. Due to the high quality of the products, iron concentrate sales have reached a long-term strategic partnership with Pangang Group, and titanium concentrates are also in short supply. Now the company uses its own high-quality titanium concentrate as raw material to start the construction of the first phase of the 80,000 t/year sulfuric acid rutile titanium dioxide project, extending the titanium industry chain and further developing the circular economy.

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