CN1037493A - The method of removing the evil of deposition red soil in the aluminum oxide production process - Google Patents

Abstract

Deposition red soil can be earlier reaches 35-60% (weight) by for example filtering to dewater to its solids content in the aluminum oxide production process.In this material, add consumption with red soil in solids content count being the containing CaO lime and thorough mixing of white lime or unslaked lime form on request of 5-8% (weight) and the fluidised form homogeneous material mixture that reduces greatly of viscosity, be that available this mixture forms stable tip then.

Description

The method of removing the evil of deposition red soil in the aluminum oxide production process

The present invention relates to the method for removing the evil of deposition red soil in the aluminum oxide production process.

Known available technology pure alumina (alumina) makes aluminium.Aluminum oxide obtains by exploitation bauxite.In the performance history the non-irrigateiest employing be sodium bicarbonate, but in modernism, adopted sodium hydroxide.The red soil that produces in so-called Bayer process process is component useless in the aluminium metallurgy process, is the by product of bauxite.Red soil is a kind of highly basic suspensoid hot in nature, wherein except iron, and the oxide compound of silicon and aluminium and also have rare-earth oxide outward.

Claim red soil for connecting soil on the soil mechanics, wherein do not have a large amount of macrobead components.Finely divided, particulate also has that the solid phase particles skin is surrounded by hydrate in the material of tixotrope character, and these hydrates are stable especially, so liquid phase and solid phase just may be extremely separately difficult.Red soil itself can not form slag dump.Alkali content is big and can infiltrate soil and polluted underground water that is to say in the liquid phase, and with regard to environment protection, this is a kind of extremely dangerous material.If do not have the waterproof soil layer on the mineral deposit, that just can only be with the separation method of costliness especially, blocks effusive underground water or otherwise the alkaline water that infiltrates in the soil is stopped.Make it be difficult to handle non-dangerously because of red soil has disadvantageous physical properties, in fact red soil is in a liquid state, and therefore just can only be stored in the treating pond.Because alumina producing factory will discharge hundreds and thousands of cubic metres red soil every year, so just can only consider that surrounding treating pond with earth comes it is disposed.But the red soil of storing in the earth pond that still has free surface is also always unsafe, because enter that wherein animal can be drowned and slowly the liquid phase of seepage can polluted underground water, because in fact always do not adopt above-mentioned expensive sepn process.This situation is difficult to change because of the solvency action of precipitation becomes again more.

In order to overcome above-mentioned shortcoming, the red soil of having advised pre-filtering has been reduced water-content with contain can bonding CaO flying dust mix and through placing (sclerosis) hole when filling up surface mining or deep-well mining with this mixture afterwards in 1-2 days, but wherein mixture solidified also terminal storage get up.The shortcoming of this method is, the flying ash in electric power plant that is suitable for finishing this task has only finite quantity for adopting, because satisfactory adhesive effect can only use the property flying dust that produces from the coal in some mining area just guaranteed.In addition, the waterpower requirement that this flying dust is made mixture can cause energy expenditure to be doubled and redoubled, because mixture viscosity is high especially.

The present invention promptly proposes the method for removing the evil of red soil, adopt this method can be by all available tackiness agents basically and red soil is formed tip, wherein the viscosity of uncured mixtures of materials is littler than the mixture that obtains with flying dust, the energy expenditure in the time of therefore can reducing phase flow pipeline hydraulic transportation effectively.

The present invention is based on a kind of like this understanding, be when water-content is reduced to a certain value back with the lime thorough mixing by for example filtering in the red soil, then can obtain fluidised form and can the waterpower mode carry out the mixtures of materials of good transportation, this mixture can extremely promptly bond and not be harmful to the material of environment and discharge.Since be added with lime, the silicate in the red soil, but aluminium and iron component promptly become adhesive substance, and in other words, red soil can change into hydraulicity jointing material like this and can harden in 24-72 hour and completely solidified in 25-30 days according to its composition.If the red soil of a kind of degree dehydration is mixed with the lime of respective amount, it is bonding then can to allow whole water-contents be used for, and therefore percolating water appearance and outflow just can not be arranged or oozes out.

Based on this understanding, task of the present invention can adopt a kind of like this method to finish, the red soil that wherein reduces the water-content of red soil and will improve solids content like this mixes with hydraulic binder, allow this mixture solidified then, the feature of this method is, make solid matter content reach 35-60%(weight to dehydration) red soil in add the 5%(weight that consumption is at least the red soil solid matter content) contain CaO lime and add water where necessary, then each component is blended together the fluidised form homogeneous material, its sclerosis of relief also can form tip on demand.Lime can be on request with unslaked lime or/and the form of white lime or/or slake lime add in the dehydration red soil.And particularly advantageous is to add the 8%(weight of its consumption up to solids content in the red soil in red soil) contain CaO lime.Count 0-300l/m with the water consumption that lime adds the red soil that dewaters with the red soil amount for improving viscosity in the mixing equipment ³

Describe the present invention in detail hereinafter with reference to accompanying drawing, there is shown the technical process of the inventive method.

Send into filter plant 2 from the thin liquid shape red soil that alumina producing factory comes through pipeline 1, wherein its water-content is reduced to 40-65% and is preferably 45-55%.Containing buck is that sodium bicarbonate aqueous solution is sent into process for making alumina through pipeline 3, can reduce alumina production cost like this.Filtering the back dry weight is the material of red soil for not having oily consistence form of 35-60%, send into mixing tank 6 then and by pipeline 5 to wherein adding lime.Send water with pipeline 4 in case of necessity; In order to be adjusted to the optimization viscosity number, usually except adding lime, also may need to add water.Water and lime can be milk of lime certainly, also can add simultaneously, as adding by pipeline 5.Under abundant agitation condition, be fluidised form with the mixed red soil of lime, promptly its viscosity reduces greatly.But the flowing mixture that obtains is like this delivered to junkyard 9 and is piled tip with dozer with the high-pressure pump 7 that is provided with in the pipeline 8, and this tip itself is stable, does not therefore need to make the accumulation circle with any other material.Also show the throughput direction or the flow direction of material in the accompanying drawing by pipeline.

Consider the far and near and conventional factor of alumina producing factory and waasteyard,, and near waasteyard, e Foerderanlage can be set, mixing device and pump not only in alumina producing plant area.

Below describe the present invention in detail with embodiment.

In the future the high water content red soil of self-alumina factory filter and solids content is a 53%(weight) red soil.Add 50Kg white lime and 250 premium on currency by every cubic metre in this dehydration red soil and these components were mixed 40 minutes and make its homogenizing.Promptly obtain the flowable material that viscosity is 3.0-5.0Pa.s after the mixing, the frictionloss good and when carrying in pipeline of its pumping reduces at double.This flowable masses mixture is pumped into the area that forms tip.Material can bond after about 10-12 hour.Reach 200-300KN/m after 3 days ²Ultimate compression strength in the same way, after 28 days, then reach 500-600KN/m ²Ultimate compression strength in the same way.This material is handled with dozer can form the satisfactory tip of specification.The water-permeable of solidifying tip is 10 ^-6-10 ^-7Cm/sec.

Advantage of the present invention is as follows:

Greatly improved the hydraulicity characteristic of red soil owing to mixing with lime, this is showing especially obviously aspect viscosity that effectively reduces mixture. This makes again mixture can resemble the red soil one of processing with flying dust Sample is carried, but its friction loss and energy consumption greatly reduces, and wherein can make to reach with one of amount of lime relevant with the red soil water content and specifies in advance bonding and mixture curing characteristics by regulating component.

The liming amount can be so definite, wherein make filter or dehydration after the red soil water content all participate in bondingly, so just can not have water to discharge from mixture, what namely guarantee can not occur in the soil polluted underground water contains the alkali fluid. Solidify that material is in the connection attitude in the tip, thus during precipitation not therefrom stripping be harmful to the material of environment. The water penetration of hardened material is especially low (K=10 generally^-6-10 ^-7Cm/sec). Can set up stable tip itself with mixture, this need not to make the accumulation circle with other material.

According to the present invention, also can make in all cases red soil become innocuous substance, the invention solves permanent insoluble environmental protection problem thereby make.

Certainly, in any case the embodiment that the present invention also can not only limit to provide above, but can in the protection domain of claims definition, implement in many ways.

Claims (4)

1, the method for removing the evil of deposition red soil in the aluminum oxide production process, the red soil that wherein reduces the water-content of red soil and will improve solids content like this mixes with hydraulic binder, allow this mixture solidified then, the feature of this method is, solid matter content is reached add in the red soil of 35-60% (weight) consumption to be at least the containing CaO lime and add water where necessary of 5% (weight) of red soil solid matter content, then each component is blended together the fluidised form homogeneous material, its sclerosis of relief also can form tip on demand.

2, the method for claim 1 is characterized in that, lime with unslaked lime or/and white lime or/and slake lime or/and the form of milk of lime add in the dehydration red soil.

3, claim 1 or 2 method is characterized in that, add to contain the 8%(weight of CaO lime consumption up to solids content in the red soil in the red soil).

4, the method for one of claim 1-3 is characterized in that, the water consumption that adds in the dehydration red soil is counted 0-300l/m with the red soil amount ³

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