Central Primary School or village primary school

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2. We are all made of bones. We can control it freely. 40 is not much. Let's do it manually

3.

Australia and some African countries continue to explore and develop heavy mineral placers such as titanium and zirconium

The xolobeni project on the coast of eastern South Africa (Eastern Cape) has identified and estimated resources of 313 million tons, with a total heavy mineral grade of 5.4% and ilmenite grade of 2.9%. The deposit is about 200 km south of deban

The heavy mineral placer along the coast 100 km north of Dakar, Senegal, was explored by an American company from 1990 to 1993. It contains 723 million tons of resources and 2.66% of heavy minerals

The rutile placer mine in Sierra Leone started proction in 1979 and stopped proction in 1995 e to civil war. Now WGI heavy minerals is working. The proven and probable reserves of the deposit are 278 million tons and 1.43% of rutile can be recovered; In addition, 185 million tons of resources can be recovered and 1.2% of rutile can be recovered

Rio Tinto is promoting the development of heavy mineral Placer in southern Madagascar, with high-grade ilmenite reserves of 75 million tons (60% TiO < sub > 2 < / sub >), which is expected to be put into proction in the third quarter of 2008

the feasibility study on the heavy mineral placer of the so-called "corridor zone" along the coast of Mozambique was completed in 2002. The No.1 deposit has 2.7 billion tons of confirmed and inferred resources, which is composed of two blocks, one is 1.765 billion tons, and contains 4.14% ilmenite; The other is 908 million tons, containing 3.8% ilmenite. The proved and estimated reserves are 807 million tons, containing 4.65% ilmenite, 0.17% zircon and 0.02% rutile, which are deposited in ancient aeolian nes

There are 144 million tons of proven reserves in the poncarie project of bemax company in Murray basin, Australia, containing 3.2% of heavy minerals (53.09% of which are ilmenite, 16.75% of which are anatase, 9.72% of which are rutile and 9.40% of which are zircon); The estimated reserves are 57 million tons, containing 2.2% heavy minerals (69.85% ilmenite, 8.09% ilmenite, 1.10% rutile and 11.15% zircon). The ginkgo deposit has proved and estimated reserves of 186 million tons, containing 2.9% heavy minerals (46.1% ilmenite, 19.71% rutile, 12.1% zircon). The company recently discovered a heavy placer deposit in the central part of the basin (part of New South Wales), 9 km × The estimated resource is 110.6 million tons, containing 4.26% heavy minerals, 12% rutile, 62% ilmenite and 18% zircon. The Murray basin in southern Australia (across NSW, Victoria and South Australia) has a total of about 40 million tons of heavy mineral resources by the beginning of 2002. The large-scale ginkgo deposit (located in South Australia) has identified and inferred 205 million tons of resources, containing 3.2% of heavy minerals; Snapper (located in South Australia, 10km away from ginkgo, discovered in 2000) has 109 million tons of mineral resources and 4.8% of heavy minerals (rutile accounts for 9% - 21% and zircon 7% - 16%); The estimated resources of Gallipoli deposit are 461 million tons, containing 2% of heavy minerals; The estimated resources of yabbie deposit are 302 million tons, containing 1.9% heavy minerals; The estimated resource of shamrock deposit is 129 million tons, containing 2.3% heavy minerals; The estimated resources of crayfish deposit are 144 million tons, containing 1.5% heavy minerals; The laburnum deposit is estimated to have 70 million tons of resources and 2.9% of heavy minerals; Winchester deposit is estimated to have 103 million tons of resources and 4.1% of heavy minerals. Mindarie heavy mineral placer project in South Australia is drilled with 6702 holes and 103600 meters, with a total resource of 262 million tons, containing 2.33% heavy minerals, of which nearly 18% are rutile and perovskite, 49% are ilmenite, and more than 25% are zircon. In the Eucla basin of South Australia, the jacinth deposit discovered recently is estimated to have 108 million tons of resources, containing 6% of heavy minerals, 55% of which are zircon, 7% rutile and 22% ilmenite. Ambrosia deposit was discovered two kilometers north of it. It is estimated that the resource is 54 million tons, containing 3% heavy minerals, 55% zircon, 7% rutile and 14% ilmenite. In the Coburn project in Western Australia (in the south of Carnarvon), most of the resources are in the Amy zone, with an estimated resource of 250 million tons and a heavy mineral content of 1.4%; The estimated resource is 460 million tons, containing 1.4% heavy minerals. The resource of Dongara heavy mineral project, 35 km north of the important Eneabba heavy mineral deposit in Western Australia, has increased to 181.6 million tons, containing 5% of heavy minerals

4. There are two main beneficiation processes for ilmenite, i.e. "gravity separation high intensity magnetic separation flotation" and "gravity separation high intensity magnetic separation electric separation (sulfur removal before separation)". In the beneficiation process, the ilmenite should be selected strictly according to the particle size, and different technological processes should be adopted. The beneficiation process of ilmenite varies greatly according to different deposit types. In primary ilmenite, most ilmenite exists in the form of vanadium titanomagnetite. Most of the titanium in this kind of ore exists in the form of independent ilmenite. A small amount of ilmenite coexists with magnetite, which is difficult to separate. In addition, it contains other titanium minerals such as rutile. Generally speaking, the grade of primary ilmenite concentrate is difficult to exceed 48%, while the grade of ilmenite concentrate with more than 50% can be selected from placer type, especially from sea sand ilmenite weathered by pegmatite.

5. 1、 Conventional flotation
the most commonly used collectors are oleic acid, oxidized paraffin soap, tar oil and some new collectors. One of the most commonly used is oleic acid and its soap. The application technology of this kind of collector is very mature and more reliable. However, it also has one of the most significant shortcomings, that is, the amount of material is too large. Oxidized paraffin soap is a kind of material obtained from the saponification of paraffin after oxidation. This collector has a wider source, and is more inexpensive. To some extent, it can replace oleic acid and its soap. However, the beneficiation efficiency of this collector is relatively poor, and the grade of the concentrate is not stable enough. Tar oil is the acidification proct of Tar Soap. Compared with oxidized paraffin soap, the ore grade selected by this collector is more stable. However, emulsification is also needed to ensure its collection effect before flotation. Compared with the above conventional collectors, the new collectors have better selectivity, generally do not need emulsification, and have better separation effect for some minerals which are difficult to separate. For example, in mineral processing, the floatability of ilmenite and augite is close, so it is difficult to separate them by flotation. After the use of some new collectors, they can be better separated and the ore grade can be greatly improved< Second, flocculation flotation can be subdivided into selective flocculation and hydrophobic flocculation. Among them, selective flocculation means that in the mixture composed of two or more minerals, a single mineral is agglomerated first and then separated step by step. Hydrophobic flocculation is a method of using the hydrophobic interaction between hydrophobic particles suspended in water to make them attract each other and coagulate into clusters, and then separate them. This method can improve the grade of raw ore from less than 10% to 40% to 50%, and greatly increase the efficiency of recycling, making it reach or even exceed 50%< The agglomerate flotation method is used for the agglomerate flotation of ilmenite, which means that the collector adsorbed on the surface of ilmenite makes the ilmenite hydrophobic, and then the particles are agglomerated by the capillary force of the bridge liquid, and the separation is carried out after it floats up. It should be noted that in the process of mineral processing by agglomeration flotation, the intensity and strength of stirring must be ensured at all times, so as to make the ore particles more easily agglomerate and achieve the effect of cleaning. When using agglomeration flotation to recover ilmenite, sodium oleate 3.5kg/t is recommended as collector and oxalic acid 1.5kg/t as inhibitor. After agglomeration flotation, the concentrate grade can reach more than 45%, and the recovery rate can reach or even exceed 75%. However, if the stirring intensity is not enough, the recovery rate may drop by 4% to 5% or even more. In addition, the impeller diameter and its position in the cell will also affect the flotation index. When the impeller diameter reaches about 50% of the stirred cell diameter and the impeller is about one meter away from the bottom of the cell, the agglomeration flotation method will have the best effect.

6. I think if your children are studious, they should be sent to the Central Primary School. After all, the conditions there are better. But if your children are playful, it's better to stay in the village, because once they are far away, their growth direction is difficult to control!

7. < UL >

the key lies in the graation of primary school. If the junior middle schools corresponding to the two primary schools are the same, it is recommended to go to the village, which is close to home, and there is no need for primary schools to compete too hard

if the primary school is different from the primary school, it is suggested to choose the primary school with relatively good policy

ecation has to start with dolls

8. In terms of school running conditions, the Central Primary School in the town is better than that in the village
as far as indivials are concerned, what suits them is good.

9. After the founding of the people's Republic of China, a central primary school was set up at the township (people's commune) level, and a village primary school was set up in each village (proction brigade). With the acceleration of aging, the proportion of young children is declining, the number of primary school students is decreasing, and all villages and small schools begin to merge. Many places only retain boarding central primary schools
the primary school system in New China abolished the distinction between junior primary school and senior primary school in the period of the Republic of China, and implemented the consistent system of primary school, which has five-year system and six-year system. Due to the implementation of nine-year compulsory ecation, the examination system is no longer implemented for primary school to junior high school
the development of schools is restricted by the local economy and the real society, which is e to the conditions. But as the internal atmosphere of the school, it is basically an independent and closed small society. The labor of leaders and teachers is both indivial labor and collective labor.