JPS6060957A - Use of waste matter and heat from lime stone baking facilities - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed description of the invention] The present invention applies when limestone is fired in a vertical furnace.

Conventionally, rough stones were first washed with water to remove fine particles and powder that adhered to the rough stones, and then returned to waste. This will increase the usage rate.

Limestone 8 When firing limestone, if the limestone in the form of lumps or granules is crushed and sized to the desired size and the rough stone is directly put into the vertical furnace, the fine particles and powder attached to the rough stone will stick to the inner walls of the furnace, etc. However, it has the disadvantage that it causes uneven flow in the gas flow in the furnace, the flow of raw stone, etc., causing uneven firing of 1 limestone, and deteriorating the quality of 1M products.

For this reason, conventionally, before charging sized limestone into a furnace, the raw stone was washed with water to remove 1 Mu grains and fine powder, and then the sized raw stone was charged into a vertical furnace and fired.

By the way, as shown in Table 1, about 90% of the fine particles and powder that are removed by washing the raw stone with water have a particle size of less than 1. ,
Even after dehydration and recovery, it remains in the form of mud containing about 15 to 20 grams of water, and conventionally it has been disposed of as waste. The composition is mainly calcium carbonate as shown in Table 2, and the particle size is usually 1.
? It has the same ingredients and the same particle size as the calcium carbonate produced in 1-200 mesh pass 85 inch.

Table 2 Therefore, 1. The present invention provides fine particles of limestone, which were conventionally disposed of,
The powder is dried using waste heat from the kiln and commercialized as calcium carbonate, making effective use of materials.

Things that can increase the utilization rate of equipment are as follows.

The method and embodiment according to the present invention are as shown in FIG.
The raw stone is fed into a container, cut out in a fixed amount by a cutting feeder 22, and guided to a separate drum washer on a conveyor. Circulating water 16 and appropriate clean water 15 are injected into the separate drum washer to wash the rough stone and adhere to the rough stone. fine grains.

Wash away fine powder.

The washed rough stone is conveyed by a conveyor to a vibrating sieve, where it is sieved and fine powder 12a is removed.

After the rough stones of appropriate size on the vibrating sieve are stored in the rough stone intermediate tank n, an appropriate amount is lifted to the top of the furnace by a skip hoist path and fed into the firing furnace 31, where it is fed into a 1M product discharge feeder (,
The product is stored in a product tank 35 via a container 34.

On the other hand, the water used to wash the raw stone separately from the drum washer is led to the tartarsifier 41, where coarse and fine particles 12 are removed.
It is led to a sedimentation tank 42, also called a sikuna. The sedimentation tank 4
At step 2, the fine particles and powder contained in the water settle, and the supernatant liquid is sent as circulating water 16 to the suction vignetting and drum washer by the pump 43, where it is used again to wash the rough stone.

Further, the settled fine particles are transferred by a slurry pump to a filter press or a centrifugal separator 46, and the centrifugal separator etc. 46 dehydrates the water to about 15 to 20 g and forms a cake into a cake hopper 47. stored in

The stored cake is cut out in a fixed amount by the supply feeder 4B,
It is put into the dryer 51 and dried. The dryer 51
In other words, conventionally, the burner 3 is heated using a steam heating type drum that utilizes the exhaust heat of the furnace 31.
2h5? Heat is recovered from the high-temperature exhaust gas by preheating the combustion air sent to the waste heat boiler a, but in this embodiment, the heat recovered in the heat exchanger 36 is used to recover thermal energy in steam in the waste heat boiler a. Steam is sent to the dryer 51 and serves as a heat source for drying the cake. The evaporated water is then separated from dust in a vapor collector passage and discharged to the atmosphere through a vapor exhaust fan.

Note that heat recovery from exhaust gas is not limited to the case where steam is recovered using a waste heat boiler. Sometimes the cake is sent to dry.

The fine grains and powder transferred by this dryer 51 are conveyed to a conveyor 5.
At step 2, the powder is transported and stored in a powder tank 55. However,
A part of the powder is distributed by the powder distribution chute 53 as appropriate.

Returning to the supply feeder 48, the moisture content of the cake 'a'A M
Preliminary preparation and cake handling may be required.

As mentioned above, the present invention provides a method for disposing of waste materials for limestone firing equipment, which is characterized in that particles and powder in waste water from washing limestone are turned into dry powder using waste heat of firing furnace exhaust gas. This is a heat utilization method.

In this invention, the fine grains and powder of raw stone, which were traditionally discarded due to their muddy nature, are dried using the waste heat of the furnace.
Therefore, it is a method that can add commercial value to lucium carbonate, and it is possible to further increase the utilization rate of materials and U-forming equipment in a limestone kiln.

[Brief explanation of drawings]

FIG. 1 is a flowchart showing one embodiment of the present invention. 10=limestone, 12=fine grains, 15-fresh water, 16=circulating water, 21=raw stone receiving hopper, 22=cutting feeder, 23
．． 25.34.52 = conveyor, 24 = drum washer, 2G = vibrating sieve, 27 = raw stone intermediate tank, 28 = skip hoist, 31 - kiln. 32 - burner, 33 = product discharge feeder, 35 = product tank, 36 = heat exchanger s a7-45 heat foiler.蕊=Heaha dust collector, 39=vapor exhaust fan. 41=combifier, 42=sedimentation tank, 43=pump, 45=slurry pump, 46=centrifuge. 47=cake hopper, 48-supply feeder, 51=dryer, 53=distribution chute, 55=powder tank.

Claims (1)

[Claims] A method for utilizing waste waste heat of a limestone calcination facility, in which fine particles in waste water from limestone calcination facilities are washed with water, and powder is made into a dry powder using waste heat from a calcination furnace exhaust gas.