Test and application of various joint processes in Baotou Steel Concentrator

Baotou Steel beneficiation plant is one of the largest iron ore processing plant China, the Bayan Obo iron ore processing. Baiyunebo ore is iron, rare earth, niobium, fluorine-based, and phosphorus, manganese, potassium and other metal deposits symbiosis. The ore is divided into rich oxidized ore according to the grade of iron grade and oxidation degree; the middle and the poor oxidized ore and magnetite mine are classified and sorted. Therefore, various types of sorting processes have been formed in the design and production of the plant.
The original design of the plant is 8 series, the first, second and third series adopt the flotation method to treat the rich oxidized ore; the fourth and fifth series use the magnetic separation method to treat the magnetite; the sixth, seventh and eighth series adopt the roasting magnetic separation method. Treatment of medium and poor oxidized ore.
Since the original design did not consider the comprehensive recovery of valuable metals such as rare earths, and the mining and sorting operations encountered many problems in actual production, many modifications were made to the original design process. Among the 7 series that have been built, only the 1 and 2 series are constructed according to the original design process, and other series of process plans have undergone major changes.
The process transformation is carried out on the basis of the test results of the sorting process and the sorting equipment in each period. Mainly to solve three problems: First, to achieve comprehensive recovery of rare earth metals; second, to improve the selection of iron minerals; third, to adapt to the ore structure changes directly into the furnace after the rich ore. Of the seven beneficiation series that have been built so far, there are five types of process types.
The practice of trial and production and remodeling of the factory over the years has shown that in order to comprehensively recover the useful minerals in the Bayan Obo ore, a joint process involving multiple beneficiation processes must be used.
A Experimental Study on Selective Flocculation and Desliming Selective flocculation is a new mineral processing process that has made significant breakthroughs in the treatment of fine-grained iron minerals in the 1970s. The Beijing Research Institute of Mining and Metallurgy carried out a lot of experimental research work on the separation of fine-grained hematite and iron-containing silicates in the study of the beneficiation method of Baotou Bayebo iron ore. Finally, the separation method of selective flocculation with water glass or water glass and sodium hydroxide was studied, and a flotation-selective flocculation process was proposed. The test indicators obtained by the semi-industrial test are: concentrate grade iron content 62.83%, fluorine content 0.2%, phosphorus content 0.1%, iron recovery rate 82.4%. On the basis of semi-industrial trials, the No. 2 series is based on this in 1981. The process was modified and an industrial test was carried out in 1984. The process structure is shown in Figure 1.

The design indicators of the process are: original ore grade 29.90%, iron concentrate grade 60%, iron recovery rate 78.04%. The main features of the process are: firstly mill the ore to -200 mesh account for more than 95%, concentrate and dehydrate, use hydrogen A combination of sodium oxide, water glass, and oxidized wax soap, in an alkaline slurry having a pH of 9, one rough selection, one sweep, two selective flotation processes, and barite , fluorite , The easy-floating minerals such as rare earths are selected. The products in the tank are iron and iron-containing coarse concentrate containing iron silicate minerals. Thus, the minerals are divided into two groups and treated separately.
Under the condition of adding sodium hydroxide and water glass, the iron-containing coarse concentrate is ground to -400 mesh to occupy 97.43% (or -325 mesh 98.6%), and the first stage is selectively flocculated and deslimed. Sodium hydroxide and water glass are added, and the second, third and fourth stage closed-circuit selective flocculation and de-sludge are carried out after the slurry is adjusted. The sedimentation of the fourth-stage de-slipping bucket is a high-quality iron concentrate with low fluorine and low phosphorus.
The first industrial test was carried out from April to December 1984. The result was 32.90% of the original ore grade, 63.30% of the iron concentrate grade, and 84.30% of the iron recovery rate. The index obtained by the process is advanced, and the mineralization of the fine-grained ore is opened. A way. [next]
B weak magnetic-strong magnetic-flotation comprehensive recovery
The process of iron, tantalum and rare earth process is proposed by Changsha Research Institute of Mining and Metallurgy on the basis of a large number of experimental research work. It is characterized by weak magnetic separation when the grinding grain size reaches -200 mesh and accounts for 95-96%. The magnetic iron mineral is recovered, the iron-containing silicate is discarded by strong magnetic separation, and the rare earth mineral and the strontium mineral are preliminarily enriched in the strong magnetic ore, and the strontium mineral is recovered by flotation method from the strong magnetic medium ore. Rare earth minerals achieve the purpose of comprehensive recovery of iron, antimony and rare earth. According to the test, the obtained indicators are: the ore has an iron grade of 30.50%, the iron concentrate grade is 65.29, and the iron recovery rate is 77.13%. The rare earth and antimony concentrates are also very good. At present, verification of industrial tests has been obtained.
C. Foreign recommendation process for processing its ore.
This process is provided by the German company Khod (KHD), the principle process is shown in Figure 2.

The characteristics of the process are: the whole process adopts the priority joint beneficiation process, the stage grinding, and the stage selection. According to the optional characteristics of useful minerals, magnetite, fluorite, hematite, rare earth minerals and antimony minerals are selected in turn, and the tailings are finally discarded. Magnetic iron is recovered by weak magnetic separation; fluorite is recovered by positive flotation, hematite is recovered by strong magnetic-positive flotation process; rare earth mineral is recovered by positive flotation-re-election method; The small test indicators are: the ore grade of iron ore is 30.87%, the grade of iron concentrate is 65.90%, and the iron recovery rate is 74.10%. The valuable elements such as rare earth, antimony and fluorine are all fully recovered. main problem:
(1) The final grinding particle size is too fine, and the content of -20 μm is increased. Generally, it is 33 to 42% in the concentrate, and the individual is as high as 85% or more. The grinding operation and the concentrate filtration operation are difficult.
(2) In the test, the company used the self-made Jones-type strong magnetic separator, the operation enrichment ratio was large, and the grade of the strong magnetic concentrate was increased by 33 to 43%, and the various types used in the production and test of Baotou Steel Plant. Strong magnetic machine, concentrate grade can only be increased by 12 to 15%. Therefore, the performance of the Jones-type strong magnetic separator for industrial production in the future should be verified.
(3) Some of the agents used in the test are not available in China. How to obtain the equivalent agents in the future, as well as the source and cost of these agents, should also be considered. In order to finalize the practical value of this process and the reality and possibilities of transition to large-scale industrial production.

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