CN1322673A

CN1322673A - Diatomite purifying treatment method

Info

Publication number: CN1322673A
Application number: CN 01129546
Authority: CN
Inventors: 邱德瑜; 盛桂云; 吴仙花; 张桂珍; 尹承滨
Original assignee: Changchun Institute of Applied Chemistry of CAS
Current assignee: Changchun Institute of Applied Chemistry of CAS
Priority date: 2001-06-26
Filing date: 2001-06-26
Publication date: 2001-11-21
Anticipated expiration: 2021-06-26
Also published as: CN1111132C

Abstract

The diatomite purifying treatment process is a two-step baking one, which eliminate sand while changing the crystal structure of inorganic impurity to activate and to raise the capacity of organic to reaction with acid. Adding sulfuric acid into diatomite and baking under the temperature below 300 deg.C can obtain high purity porous and fine SiO2 without needing pressure.

Description

Diatomite purifying treatment method

The invention belongs to diatomite purifying treatment method.

Diatomite is by the natural SiO2 that ancient times, siliceous high algae silication formed, and has that particle diameter is little, porous, characteristics such as specific surface is big, adsorptivity is strong, high temperature resistant, antiacid, low price, very big using value is arranged.Handle diatomite and come down to manage to remove impurities.Processing in the past mainly is for the requirement of diatomite as catalyst carrier and filter aid, is to adopt acidleach to boil basically, makes impurity and acid effect, forms soluble compound and is removed.This way has following deficiency: 1, acidleach boils that to remove the organic impurities effect little; 2, impurity is not simple Al in the diatomite ₂O ₃, Fe ₂O ₃, the compounds such as MgO, CaO, but complicated silicoaluminate and iron compound.This class impurity will could be destroyed by acid under higher temperature, is converted into SiO ₂With the aluminium of solubility, molysite and be removed, now use 31%H ₂SO ₄, at 106-108 ℃ of digestion or use 40%H ₂SO ₄At 110 ℃ of digestions.Such treatment temp is destroyed the impurity reaction to acid, still seems very low.So reaction speed is little, the digestion time is long, effect owes thorough.Can only pressurize in tightness system and carry out if will improve digestion temperature again, its facility investment is very big, unrealistic; Acid amount used when 3, acidleach is boiled is much larger than quantum volueris, thereby last spent acid treatment capacity is also very big; Bigger when 4, acidleach is boiled to equipment corrosion, increased cost; 5, acidleach is in the past boiled diatomaceous foreign matter content after the processing to as filler, still seems big slightly, does not satisfy service requirements.Therefore, how thoroughly removing organic impurities, improve treatment temperature, increase impurity with the speed of acid reaction, reduce the consumption of acid, is to solve the key that diatomite is processed.

The purpose of this invention is to provide a kind of diatomite purifying treatment method, adopted for two steps burnt, namely reach the desanding purpose, change simultaneously the crystal structure of inorganic impurity and activate, strengthen impurity itself with the ability of acid reaction, sulfuric acid is added in the diatomite, and in roasting below 300 ℃, need not pressurize to obtain purity height, SiO that the porous grain is thin ₂

Impurity silicoaluminate and iron cpd etc. in the diatomite require to carry out in the temperature far above 110 ℃ with acid-respons.This is that aqueous acid system institute is inaccessiable, but about 340 ℃ of vitriol oil boiling point, desires to reach to improve treatment temp, increase the speed of response of destroying impurity, only abandons aqueous solution acidleach and boils.Therefore, the present invention adopts the processing method of two step burnings, reaches the desanding purpose.The first step: will go the diatomite of mud, sand at high temperature to burn.Its purpose: the one, fully oxidize away organic impurities, the 2nd, change the crystalline structure of inorganic impurity and activate, strengthen the ability of impurity itself with acid-respons.Second step: sulfuric acid is added to roasting in the diatomite, and acid can be penetrated in the diatomite micropore equably, along with temperature raises, and water evaporates, acidity increases in the micropore, and it is more thorough to remove in the micropore impurity, thereby can obtain purity height, SiO that the porous grain is thin ₂, can need not pressurize carrying out below 300 ℃.Like this, improve impurity with the acid-respons temperature, this difficult problem has just solved.This strengthens the reactive behavior of impurity own and improves the acid treatment temperature, and impurity in the diatomite is accelerated to remove in these two aspects, and both are indispensable one, and this is the basis of head it off.

The present invention washes desilt, sand with diatomite, burns at 500-550 ℃ of high temperature to add H in 1-1.5 hour ₂SO ₄, addition is H ₂SO ₄: the impurity percentage by weight be 1.1-1.3 at 220-280 ℃ of roasting 2-2.5 hour, water extraction adds and to contain 1% except the washing of Fe agent liquid, filters, drying, namely gets purity and is: SiO ₂More than 90%, Al ₂O ₃Below 0.04%, Fe ₂O ₃0.4 following white diatomite.

Technology secondary pyroprocessing of the present invention improves the acid treatment temperature greatly, has accelerated processing reaction speed, shortens the treatment time, only 3,4 hours.This treatment temp does not reach H ₂SO ₄Boiling point, acid mist is little, does not also reach aluminium, molysite decomposition temperature, does not produce aluminium, iron, sulfur oxide.Boil ratio with acidleach, reduce, so equipment corrosion reduces, help reducing cost with the acid amount.

Embodiment provided by the invention is as follows:

Embodiment 1:

Diatomite SiO after the 30 gram washings ₂Content 85%, Fe ₂O ₃2%, Al ₂O ₃6%, burnt 1 hour at 500 ℃ earlier, add 1.28H after cold ₂SO ₄25ml mixes thoroughly, in 250 ℃ of roastings 2 hours, soaks, divides the waste water of leaving away, and with containing the washing of 1% iron removing reagent liquid, filters, dries again, obtains white products.It consists of: SiO ₂Content 91%, Fe ₂O ₃0.4%, Al ₂O ₃0.033%.

Embodiment 2:

Diatomite after the 30 gram washings, SiO ₂Content 82.50%, Fe ₂O ₃2.5%, Al ₂O ₃2% burnt 1.5 hours at 500 ℃, added 1.28H after cold ₂SO ₄30ml, mixing in 280 ℃ of roastings 2.2 hours, soaks, goes waste liquid, adds the washing of iron removing reagent liquid, filters, dries, and gets white products, and it consists of: SiO ₂Content 91%, Fe ₂O ₃0.24%, Al ₂O ₃0.037%.

Embodiment 3:

Diatomite SiO after the 30 gram washings ₂Content 76.12%, Fe ₂O ₃11.83%, Al ₂O ₃19.1% burnt 1 hour at 550 ℃, added 1.4H after cold ₂SO ₄30ml after mixing thoroughly, puts 220 ℃ of roastings 2.5 hours, and waste liquid is removed in immersion, adds iron removing reagent liquid washing, filtering drying, white diatomite, consist of SiO ₂Content 91%, Fe ₂O ₃0.4%, Al ₂O ₃0.04%.

Embodiment 4:

Gram diatomite after 30 washings, SiO ₂Content 57.50%, Fe ₂O ₃3.09%, Al ₂O ₃8.4% burnt 1.5 hours at 550 ℃ earlier, added 1.30H after cold ₂SO ₄35ml mixes thoroughly, and roasting is 2.5 hours in 250-280 ℃, and immersion is removed waste liquid, added iron removing reagent liquid and wash several times, filter, after the oven dry to white diatomite, consist of: SiO ₂Content 91.3%, Fe ₂O ₃0.27%, Al ₂O ₃0.034%.

Claims

1. a diatomite purifying treatment method is characterized in that diatomite is washed desilt, sand, burns at 500-550 ℃ of high temperature to add H in 1-1.5 hour ₂SO ₄, addition is H ₂SO ₄: the impurity percentage by weight be 1.1-1.3 at 220-280 ℃ of roasting 2-2.5 hour, waste liquid is removed in immersion, adds to contain 1% except the washing of Fe agent liquid, filters, drying, namely gets purity and is: SiO ₂More than 90%, Al ₂O ₃Below 0.04%, Fe ₂O ₃0.4 following white diatomite.