CN102382920B - Method for decreasing phosphorus of high-phosphorus iron ore by adopting microwave reduction-magnetic separation - Google Patents

Abstract

The invention discloses a method for decreasing phosphorus of high-phosphorus iron ore by adopting microwave reduction-magnetic separation, solving the problems that the dephosphorizing speed of the high-phosphorus iron ore is low, and the iron recovery rate and the dephosphorizing rate are low. The method is characterized by comprising the following steps: material smashing, blending, microwave reduction, sponge iron smashing, magnetic separation and post-treatment. Compared with the existing dephosphorizing method for the high-phosphorus iron ore, the method in the invention has the following benefits: high-phosphorus iron ore carbon heat reduction reaction is conducted faster and more thoroughly, the embedded structure of apatite is damaged, and the dephosphorizing rate and the iron recovery rate are improved by magnetic separation. By magnetic separation, low-phosphorus iron powder containing 0.2-0.3 percent of phosphorus can be obtained, and the dephosphorizing rate and the iron recovery rate can be more than 85 percent; and the carbon heat reduction time is short, the reduction temperature is lower than that in normal heating, the energy is saved, and the pollution is less.

Description

The method of decreasing phosphorus of high-phosphorus iron ore by adopting microwave reduction-magnetic separation

Technical field

The present invention relates to the method that high-phosphorus iron ore reduces, falls phosphorus, particularly the method for phosphorus falls in a kind of high-phosphorus iron ore microwave-magnetic choosing.

Background technology

Solve the iron ore resource shortage problem, must be conceived to the utilization of low-grade, compound mineral intergrowth resource, this also is to solve the fundamental way that the iron ore resource safety and stability is supplied with.Important Iron Ore Types such as " Ningxiang's formula " high-phosphor oolitic hematite, but because the phosphorus in the iron ore mainly exists with collophanite, phosphatic rock or francolite form, contaminate the edge in iron oxide particle, embedding is distributed in quartz or the carbonate minerals, and a small amount of the tax is stored in the lattice of iron mineral.And phosphorite crystal mainly is column, needle-like, collection crystalline substance or the embedding of shot shape and is distributed in iron mineral and the gangue mineral, and granularity is less, is difficult to select smelting, thereby substantially is not utilized effectively.

The existing dephosphorizing method of high-phosphorus iron ore has beneficiating method dephosphorization, chemical method dephosphorization, microbial method dephosphorization and smelts the dephosphorization method.It is limited that the phosphorus amplitude falls in the high-phosphorus iron ore beneficiating method, and the fine fraction iron mineral reclaims the problem such as difficulty, the easy obstruction of the lower and strong magnetic machine of receipts iron rate.Chinese patent open (bulletin) number: CN94111376.0, a kind of " high-phosphorus iron ore microbial-chemical dephosphorization method " disclosed, although phosphorus falls in Microorganism Leaching the little advantage of environmental pollution is arranged, soak the required bacterium in ore deposit and need to gather, separate, cultivate and tame.For autotrophic bacteria, there is the slow shortcoming of the speed of growth, heterotrophic bacterium then needs to have increased the manufacture cost for it provides organotrophy, and is relatively more difficult in actual applications.The chemical process dephosphorization, the large cost of acid consumption is high, and easily causes soluble iron mineral dissolution in the ore to cause the loss of iron; The ore dressing waste liquid is difficult to process, and easily causes the pollution of environment.Chinese patent open (bulletin) number: CN101487081 discloses " a kind of dephosphorization method for oolitic high phosphorus iron ore ", produces low-phosphorous molten iron with high-phosphorous reduced iron, and the method energy consumption is too high and dephosphorizing capacity is limited.

Summary of the invention

The invention provides a kind of high-phosphorus iron ore microwave-magnetic choosing and fall the method for phosphorus, solve high-phosphorus iron ore dephosphorization speed slow, receive iron rate and the low problem of dephosphorization rate.

The present invention will smelt the method dephosphorization and the beneficiating method dephosphorization combines, its gordian technique be the heat effect of utilizing the efficient all even selectivity heating of microwave with and non-thermal effect, the iron carbon mixture is carried out rapidly and thoroughly carbothermic reduction, destroy the embedding cloth structure of phosphatic rock, rhombohedral iron ore with weak magnetic in the iron ore converts ferromagnetic mineral to simultaneously, carries the iron dephosphorization for follow-up magnetic separation and prepares.

The method that phosphorus falls in high-phosphorus iron ore microwave-magnetic choosing provided by the invention may further comprise the steps:

A. material crushing, getting phosphorous massfraction is 0.6%～1%, and full weight of iron percentage composition is crushed to 90 orders～3mm greater than 40% high-phosphorus iron ore, and choosing fixed carbon quality percentage composition is reductive agent greater than 80% hard coal, is crushed to 200 orders～1mm;

B. prepare burden, high-phosphorus iron ore accounts for 75%～82% of compound gross weight, and coal dust accounts for 14%～21% of compound gross weight, and it is 1.1～1.4 that white lime is adjusted basicity, in this ratio compound is sent in the mixer and is evenly mixed;

C. microwave reduction, the compound for preparing is transported in the industrial microwave oven by belt conveyor, carry out carbothermic reduction reaction, temperature element adopts the nickel chromium-nickel silicon thermocouple with bell housing, reduction temperature is 950 ℃～1050 ℃, and microwave action power is 5KW～10KW, and be 18～30min action time, logical nitrogen protection cool to room temperature obtains sponge iron;

D. sponge iron is broken, and the sponge iron that reduction is obtained is transported in the vibrating pulverizer broken, delivers in the ball mill through two sections ball mill pulverizings again, reaches-200 orders and accounts for 6080% magnetic separation granularity;

E. magnetic separation is sent the powder after pulverizing into two stages of magnetic separation in the magnetic separator, obtains fine iron breeze and the high phosphorus slag of mine tailing of low-phosphorous rich iron after the magnetic separation;

F. subsequent disposal is sent into the fine iron breeze of the low-phosphorous rich iron that obtains in the electric furnace and to be made steel; High phosphorus slag is sent to production phosphate fertilizer.

The present invention compares its significant beneficial effect with existing high-phosphorus iron ore dephosphorizing method:

1. what the high-phosphorus iron ore carbothermic reduction reaction carried out is thorough relatively rapidly, and the embedding cloth structure of phosphatic rock is destroyed, and is improved by magnetic separation dephosphorization rate and receipts iron rate.Can obtain the low-phosphorous iron powder of phosphorus content 0.2%～0.3% through magnetic separation, dephosphorization rate and receipts iron rate can reach more than 85%.

The carbothermic reduction time short, reduction temperature is low during than conventional heating, saves the energy and pollutes little.

Embodiment

The below specifically describes the present invention take laboratory small-scale test as example.

Get high-phosphorus iron ore powder and slaked lime, high-phosphorus iron ore, slaked lime chemical composition such as table 1; Selecting reductive agent is coal dust, and coal dust forms such as table 2; The reduction microwave oven adopts the KH-6HMOA industrial microwave oven.

Table 1 high-phosphorus iron ore and slaked lime chemical composition (%)

Table 2 coal dust forms technical analysis (%)

Implementation step:

(1) with ball mill coal dust, the fine grinding of high-phosphorus iron ore powder are become 90 orders～1mm.

(2) take by weighing above-mentioned high-phosphorus iron ore powder 82.5g, coal dust 15.2g, white lime 2.28g and mixing, topmost one deck spreads coal dust, sample oxidation when preventing from taking out crucible.

(3) close KH-6HMOA industrial microwave oven power supply, the crucible that configures raw material is put into microwave oven.

(4) the heating terminal temperature of setting industrial microwave oven is 1000 ℃, and microwave action power is 5KW～10KW, heats, and be 22min heat-up time.

(5) after heating finishes, close the power switch of industrial microwave oven.

(6) open nitrogengas cylinder and in microwave oven, pass into nitrogen, when treating that micro-wave temperature is down to room temperature, from the microwave oven reactor, take out the sponge iron that reaction obtains.

(7) sponge iron that reduction is obtained is transported in the vibrating pulverizer broken, delivers in the ball mill through two sections ball mill pulverizings again, reaches-200 orders and accounts for 70% magnetic separation granularity.

(8) powder after will pulverizing is sent into two stages of magnetic separation in the magnetic separator, obtains fine iron breeze and the high phosphorus slag of mine tailing of low-phosphorous rich iron after the magnetic separation.The low-phosphorous iron powder that the obtains mark of packing in the sample sack is good, chemically examines.

Phosphorous 0.98% high-phosphorus iron ore can obtain the low-phosphorous iron powder of phosphorus content 0.21% behind above-mentioned flow process dephosphorization, receiving the iron rate can reach more than 85%.

Claims (1)

1. a high-phosphorus iron ore microwave-magnetic selects the method for falling phosphorus, it is characterized in that the method may further comprise the steps:

A. material crushing, getting phosphorous massfraction is 0.6%～1%, and full weight of iron percentage composition is crushed to 90 orders～3mm greater than 40% high-phosphorus iron ore, and choosing fixed carbon quality percentage composition is reductive agent greater than 80% hard coal, is crushed to 200 orders～1mm;

B. prepare burden, high-phosphorus iron ore accounts for 75%～82% of compound gross weight, and coal dust accounts for 14%～21% of compound gross weight, and it is 1.1～1.4 that white lime is adjusted basicity, in this ratio compound is sent in the mixer and is evenly mixed;

C. microwave reduction, the compound for preparing is transported in the industrial microwave oven by belt conveyor, carry out carbothermic reduction reaction, temperature element adopts the nickel chromium-nickel silicon thermocouple with bell housing, reduction temperature is 950 ℃～1050 ℃, and microwave action power is 5KW～10KW, and be 18～30min action time, logical nitrogen protection cool to room temperature obtains sponge iron;

D. sponge iron is broken, and the sponge iron that reduction is obtained is transported in the vibrating pulverizer broken, delivers in the ball mill through two sections ball mill pulverizings again, reaches the magnetic separation granularity that-200 orders account for 60-80%;

E. magnetic separation is sent the powder after pulverizing into two stages of magnetic separation in the magnetic separator, obtains fine iron breeze and the high phosphorus slag of mine tailing of low-phosphorous rich iron after the magnetic separation;

F. subsequent disposal is sent into the fine iron breeze of the low-phosphorous rich iron that obtains in the electric furnace and to be made steel; High phosphorus slag is sent to production phosphate fertilizer.