CN1689718A

CN1689718A - Waste sand treating method in crystal processing

Info

Publication number: CN1689718A
Application number: CN 200410034004
Authority: CN
Inventors: 尹克胜
Original assignee: Individual
Current assignee: Individual
Priority date: 2004-04-21
Filing date: 2004-04-21
Publication date: 2005-11-02

Abstract

The process of treating waste crystal processing sand with cutting fluid, iron and its oxide, crystal powder, SiC, crystal bits, etc. includes the following steps: 1. eliminating the oily cutting fluid, 2. sieving out crystal bits and other large grain impurity, 3. alkali washing to eliminate SiO2, 4. water washing and regulating pH value, 5. acid pickling to eliminate iron and its oxide and to separate reaction liquid and precipitate, 6. water washing and grading the precipitate, 7. drying, 8. packing the dried SiC material, and 9. neutralizing the reaction liquid and draining.

Description

Method for treating waste sand in crystal processing

Technical Field

The invention relates to a crystal processing waste sand treatment method, and belongs to the field of comprehensive utilization of crystal processing wastes.

Background

The inventor submits an invention patent of 'novel process for comprehensively treating crystal processing waste oil sand' with the application number of 01144627.7 in 21/12/2001 (granted in 28/12/2003), and in the subsequent industrial implementation, the original process is greatly improved, and the single treatment of the crystal processing waste oil sand is gradually expanded to the treatment of various crystal processing waste sands formed in the crystal processing.

The waste sand for crystal processing is formed in the crystal processing and contains cutting fluid (PC oil or other aqueous solution), iron and iron oxide, and crystal powder SiO₂The grain size and the composition of the mixture of the components such as the abrasive silicon carbide SiC and the crystal scraps are different from each other because the mixture is produced by the procedures of rough grinding, multi-blade cutting, rough sheet grinding, roller chamfering and the like of quartz crystal processing.

Disclosure of Invention

The invention aims to provide an economic and scientific method for treating waste sand in crystal processing, which utilizes a corresponding physicochemical method to extract and separate according to different physicochemical properties of components in a waste sand system, recovers high-value silicon carbide materials, and achieves the purposes of changing waste into valuables, recycling, eliminating pollution and protecting the environment.

The purpose of the invention is realized as follows: removing oil from waste sand (waste oil sand) containing cutting oil by adopting an oil recovery method in the new process for comprehensively treating the waste oil sand in crystal processing with the application number of 01144627.7; screening the oil-free waste sand to remove crystal debris; for SiO therein₂The treatment method of (2) is two methods: one is an alkali washing reaction method in the new process of comprehensive treatment of waste oil sand in crystal processing according to the application number of 01144627.7, and the other is a hydrofluoric acid reaction method; the rest precipitate is mixture of silicon carbide, iron and iron oxide, and is removed by acid washing method, and the acid used for acid washing is hydrochloric acid (HCI) and sulfuric acid(H)₂SO₄HNO, nitric acid₃And one of hydrofluoric acid and HF, washing with water to remove reaction residual liquid, grading, drying, packaging and metering to obtain the high-purity silicon carbide material. The detailed description is provided with reference to the accompanying drawings and examples.

Drawings

FIG. 1 is a flow chart of the treatment process of oil-containing waste sand

FIG. 2 is a flow chart of a process for treating waste sand in grinding of wool

FIG. 3 is a flow chart of acid-base washing treatment process for waste sand

FIG. 4 is a flow chart of a double acid washing treatment process for waste sand

FIG. 5 is a process flow diagram of single acid washing treatment of waste sand

FIG. 6 is a schematic diagram of the structure of an oil and alkali cleaning reactor

In the process flow diagrams of fig. 1 to 5, double arrows indicate a waste sand treatment process, single arrows indicate a reaction liquid treatment auxiliary process flow, and step 1 is an oil removal step in which an oily cutting liquid removal operation of waste sand is completed; step 2 is a screening step, and large-particle impurities such as crystal debris and the like in the waste sand are removed through screening; step 3 is an alkali washing step, as requiredAlkali washing reaction principle and process in 'comprehensive treatment new process for waste oil sand in crystal processing' No. 01144627.7Removing SiO from the solution₂(ii) a Step 4 is a water washing step for removing the chemical reaction residual liquid of the previous step; step 5 is an acid washing iron removal step, and iron oxide in the waste sandare removed through an acid adding reaction; step 6 is a water washing classification step, wherein the treated SiC precipitate is cleaned to obtain a chemical reaction residual liquid and subjected to particle size separation; step 7 is a drying step; step 8 is a packaging and weighing step; step 9 is a production wastewater treatment step; step 10 is an HF reaction step and utilizes The principle of (1) removing SiO in waste sand₂The step 11 is an HF reaction product treatment step.

FIG. 6 is a schematic diagram of the structure of an oil and alkali cleaning reactor: in the figure, 12 is an oil removal combustion furnace, 16 is an alkali washing reactor, oil-containing waste sand is added into the combustion furnace 12 from a feed inlet 13, oil in the oil is removed by combustion, combustion flue gas is discharged from a chimney 15, the combustion heat heats materials in the alkali washing reactor 16, mixed sand after combustion and oil removal falls into a material pool 14, the mixed sand is added into the alkali washing reactor 16 from a feed inlet 17 after being screened, a stirrer 18 enables the materials in the reactor to be uniformly mixed, and the process is finished in a boiling state Reaction, SiO removal₂And the reactant is discharged from the discharge port 19.

Detailed Description

Example 1

As shown in the flow chart of the oil-containing waste sand treatment process in figure 1: adding waste oil-containing sand (waste oil sand) into a combustion furnace at the lower part of the oil-removing alkaline washing reactor shown in figure 6 for combustion, and finishing the oil-removing operation of the working procedure 1; thedeoiled blanking is SiC or SiO₂Iron, iron oxide, crystal debris and the like, and screening the mixed sand in a screening process 2 to remove large-particle impurities such as the crystal debris and the like; adding the mixture into an alkali washing reactor to carry out alkali washing reaction so as to ensure that SiO in the mixture is₂Reaction with NaOH to produce Na₂O.nSiO₂Solution, reaction heat extracted by oil-removing combustionFor discharging the reaction solution intoA neutralization tank 9 for completing the alkali washing operation of the working procedure 3; the precipitate enters a water washing process 4, and Na is removed by water washing₂O.nSiO₂Residual liquid, pH value is adjusted to 7-9, the precipitate is a mixture of SiC, iron and iron oxide, the precipitate is sent to acid washing deironing process 5, hydrochloric acid is added for carrying out Carrying out acid washing iron removal reaction; discharging reaction liquid into a neutralization tank 9, and neutralizing the reaction liquid discharged in the working procedure 3 to eliminate pollution; the precipitate after the acid washing is SiC with higher purity, enters a washing and grading process 6, washes the chemical reaction residual liquid, and completes the granularity sorting at the same time; drying in the step 7; and 8, packaging and metering to obtain the qualified SiC material.

Example 2

FIG. 2 is a flow chart of a process for treating waste sand in the process of grinding wool: the waste sand is oil-free, wherein SiC is granules, iron oxide and SiO₂Is a micro powder material which can be processed by utilizing different physical properties: as shown in the figure, the waste sand is added with water for screening, large-particle impurities such as crystal debris and the like in the waste sand are removed, and the screening process 2 is completed; then, the SiO in the solution is removed by washing with water in a water washing step 4₂And part of iron and iron oxide micropowder; the rest precipitate is a mixture of SiC and iron oxide, sulfuric acid is added to react with the iron and iron oxide according to a chemical reaction equation: ； . Discharging the reaction liquid into a neutralization tank 9, removing iron and iron oxide in the reaction liquid, and completing an acid washing iron removal process 5; the precipitate after the acid washing is SiC with higher purity, and the chemical reaction residual liquid is cleaned in the step 6 of water washing and grading to finish the granularity sorting; drying in the step 7; and 8, packaging and metering to obtain the qualified SiC material.

Example 3

The process flow shown in the process flow diagram of acid-base washing treatment of the waste sand in fig. 3 is applicable to grinding waste sand without oil (or with oil removal completed): the waste sand is firstly screened and removed with crystal in the screening procedure 2BodyAfter large particle impurities such as debris and the like; containing SiC and SiO₂Washing the mixed sand of iron and iron oxide in a washing tank to remove part of water-soluble and suspended impurities, and finishing the washing process 4; adding the precipitate into an acid washing and iron removing process 5, and reacting iron and iron oxide according to a chemical reaction equation under the action of nitric acid: discharging the reaction liquid into a neutralization tank 9, removing iron and iron oxide in the reaction liquid, and completing an acid washing iron removal process 5; the precipitate is SiC or SiO₂Adding the mixture in the water washing step 4 to further remove reaction residual liquid in the mixture, and then feeding the reaction residual liquid into a neutralization pond 9, and adjusting the pH value to 5-7 to finish the water washing step 4; washing qualified SiC and SiO₂Is added to the caustic wash reactor of FIG. 6, to make SiO therein₂Reaction with NaOH to produce Na₂O.nSiO₂Solution, removal of SiO therefrom₂Completing the alkali washing operation of the working procedure 3; discharging the reaction liquid into a neutralization tank 9, and neutralizing the reaction liquid in the working procedure 5 to eliminate pollution; the precipitate in the step 3 is SiC, and enters a water washing and grading step 6, so that the chemical reaction residual liquid is cleaned, and meanwhile, the particle size separation is completed; drying in the step 7; and 8, packaging and metering to obtain the qualified SiC material.

Example 4

The process flow shown in the process flow chart of double acid washing treatment of the waste sand in FIG. 4 is applicable to grinding waste sand without oil (or with oil removal completed): firstly, adding water into the waste sand for screening, removing large-particle impurities such as crystal debris and the like in the waste sand, standing and settling slurry under the screen, removing upper turbid liquid, and finishing the screening process 2; the lower precipitate is SiC or SiO₂Iron and iron oxide, feeding the mixture into acid pickling iron removing process 5, adding hydrochloric acid, and performing Carrying out acid washing iron removal reaction; discharging reaction liquid into a neutralization tank 9, wherein the precipitates at the bottom of the tank are SiC and SiO₂Adding hydrofluoric acid (HF), HF and SiO₂According to the equation Reaction is carried out to generate H₂SiF₆Solution, HF reaction to complete Process 10SiO should be removed₂Carrying out operation; the precipitate is SiC, and enters a water washing and grading process 6, and the chemical reaction residual liquid is cleaned to finish the particle size separation; drying in the step 7; step 8, packaging and metering to obtain qualified SiC material; na (sodium sulfate)₂SiF₆The solution reacts with NaCI in reactor 11: making into sodium fluosilicate (Na)₂SiF₆) And (5) producing the product.

In order to save the reaction time, the hydrochloric acid and the hydrofluoric acid in the embodiment can be used as SiO in the waste sand₂And the iron oxide are added simultaneously in a calculated ratio, the operation of the working procedure 5 and the working procedure 10 is completed at one time, and other working procedures are unchanged.

Example 5

The flow chart of the single-acid washing treatment process of the waste sand in FIG. 5 is applicable to grinding waste sand without oil (or with oil removal completed): firstly, adding water into the waste sand for screening, removing large-particle impurities such as crystal debris and the like in the waste sand, standing and settling the screened slurry, and removing upper turbid liquid to finish the screening process 2; the lower precipitate is SiC or SiO₂Iron and iron oxide, the mixture is sent to the step 10, hydrofluoric acid (HF) is added for treatment, and SiO in the sand is mixed₂With HF as per equation Reaction takes place while iron and iron oxides react with HF A reaction takes place in which Na₂SiF₆The treatment was carried out according to the principle of the method of example 4; the washing liquid is sent to a neutralization tank 9 for neutralization treatment; the sediment at the bottom of the pool is SiC, and enters a water washing and grading process 6, so that the reaction residual liquid is cleaned, and meanwhile, the particle size separation is completed; drying in the step 7; and 8, packaging and metering to obtain the qualified SiC material.

Example 6

The sequence of the steps in the above examples can be adjusted according to actual conditions to form a new embodiment.

Claims

1. A method for treating the waste sand generated by crystal processing includes such steps as mixing cutting liquid, iron and iron oxide, and crystal powder SiO₂The waste sand of components such as abrasive silicon carbide SiC, crystal fragments and the like is separated and purified by utilizing different physical and chemical properties to produce qualified SiC materials, and is characterized in that: firstly, removing oily cutting fluid in waste sand in an oil removing process; sieving to remove large particle impurities such as crystal debris, adding acid in acid washing process to remove iron and iron oxide, and treating SiO₂Adding hydrofluoric acid for chemical reaction and removing, or adding NaOH for alkaline washing reaction and removing; discharging the reaction solution after neutralization treatment; and washing, grading, drying, packaging and metering the precipitate to obtain the qualified silicon carbide (SiC) material.

2. The method of claim 1, wherein: the oil removal process 1 and the alkali cleaning process 3 of the waste sand are completed in an oil removal alkali cleaning reactor: adding oily waste sand into a combustion furnace 12 from a feed inlet 13, burning to remove oil in the waste sand, discharging combustion flue gas from a chimney 15, heating materials in an alkaline washing reactor 16 by combustion heat, dropping dry mixed sand subjected to combustion oil removal into a material pool 14, sieving, adding the dry mixed sand into the alkaline washing reactor 16 from a feed inlet 17, and finishing the operation in a boiling state Reaction, SiO removal₂And the reactant is discharged from the discharge port 19.

3. The method of claim 1, wherein: the acid used for removing iron by pickling waste sand is hydrochloric acid (HCI), and the reaction equation of the HCI with iron and iron oxide is as follows:

4. according to the claimsThe method of claim 1, comprising: the acid used for removing iron in the pickling of the waste sand is sulfuric acid (H)₂SO₄) The reaction equation of the diluted iron oxide and iron oxide is as follows:

5. the method of claim 1, wherein: the acid used for removing iron in the pickling of the waste sand is nitric acid (HNO)₃) The reaction equation with iron and iron oxide is:

6. the method of claim 1, wherein: the acid used for removing iron in the pickling of the waste sand is hydrofluoric acid (HF), and the reaction equation of the HF with iron and iron oxide is as follows:

7. the method of claim 1, wherein: pickling waste sand to remove SiO₂The acid used is hydrofluoric acid (HF), which reacts with SiO₂The reaction equation of (a) is: