Risk assessment method for using industrial byproduct sodium hydrosulfide in beneficiation process

Abstract

The invention relates to the technical field of by-product sodium hydrosulfide production and environmental risk assessment, in particular to a risk assessment method for an industrial by-product sodium hydrosulfide in a mineral separation process. The method mainly comprises the following steps: calculating concentration limit values of risk evaluation factors in the industrial byproduct sodium hydrosulfide under different exposure approaches by a dose-reaction evaluation method, and taking the minimum concentration limit value as a standard concentration limit value according to a risk maximization principle; by comparing the concentration of the risk evaluation factor in the industrial by-product sodium hydrosulfide under different production conditions with a standard concentration limit value, the risk of the industrial by-product sodium hydrosulfide under different production conditions before mineral separation is evaluated, so that the environmental risk is reduced; the adverse effect of toxic and harmful substances brought in when the industrial byproduct sodium hydrosulfide is used for mineral separation on soil and underground water is avoided, and the method can provide process control guidance for a byproduct sodium sulfate production enterprise.

Description

Technical Field

[0001] The invention relates to the technical field of by-product sodium hydrosulfide production and environmental risk assessment, and in particular to a risk assessment method for using industrial by-product sodium hydrosulfide in a mineral processing process. Background Art

[0002] Industrial by-product sodium hydrosulfide is mainly produced by the production of dye intermediates such as sodium sulfocyanate, No. 25 sulfocyanate, butyl ammonium sulfocyanate, and pharmaceutical intermediates. The large amount of acidic sulfur-containing waste gas is absorbed by alkali to generate a by-product sodium hydrosulfide solution. Sodium hydrosulfide solution is a reducing agent. When used in the mineral processing process, especially in the flotation process of copper ore, it can accelerate the reduction reaction between minerals and oxidants and promote the flotation of minerals. In the mineral flotation, sodium hydrosulfide can react with oxidants to generate sulfides, thereby realizing the selective recovery of minerals. Since the surface of the oxidized mineral has ionic bond characteristics, the water molecules are polarized by electrostatic attraction to form a relatively firm directional hydration film and present a hydrophilic state. It is difficult for the collector to penetrate this hydration film and act on the mineral surface. The essence of sulfide flotation is to sulfide the ground copper oxide pulp by adding a sulfiding agent, and then add a xanthate collector for flotation. After adding the sulfiding agent, the sulfur-containing components are rapidly adsorbed on the surface of the oxidized mineral, presenting as a metal sulfide film. This type of MeS crystal package formed by sulfidation constitutes the medium and bridge for the adsorption of the collector to the surface of the oxidized mineral, that is, the activation center.

[0003] According to existing studies, HS - The ions can be anodized on an inert platinum electrode to produce neutral sulfur S 0 , making the electrode surface hydrophobic, while HS - Ions can also lose electrons on the surface of sulfide ores and be oxidized into hydrophobic neutral sulfur; this electron transfer leads to an increase in the potential of the slurry and causes the surface of the sulfide ores to float due to hydrophobicity, thus improving the floatability of the sulfide ores. Therefore, a large amount of industrial by-product sodium hydrosulfide produced in the production process of dye intermediates and pharmaceutical intermediates can be used for copper ore dressing.

[0004] However, since industrial by-product sodium hydrosulfide is produced from various dye intermediates and pharmaceutical intermediates, the raw materials, products and other impurities in the production process of dye intermediates and pharmaceutical intermediates may be brought into the industrial by-product sodium hydrosulfide. When the industrial by-product sodium hydrosulfide is used in the mineral processing process, the toxic and harmful substances in it may remain in the tailings. According to GB 18599-2020 General Industrial Solid Waste Storage and Landfill Pollution Control Standards, tailings that cannot be comprehensively utilized are landfilled in general industrial solid waste landfills. The toxic and harmful substances in them will enter the groundwater, surface water and soil with the landfill of the tailings, which will have an adverse effect on the soil and groundwater. Summary of the invention

[0005] In order to solve the above problems, the purpose of the present invention is to provide a risk assessment method for the use of industrial by-product sodium hydrosulfide in mineral processing. The present invention reduces environmental risks by conducting risk assessment before the industrial by-product sodium hydrosulfide is used in mineral processing, and avoids the adverse effects of toxic and harmful substances brought into the soil and groundwater when the industrial by-product sodium hydrosulfide is used in mineral processing.

[0006] To achieve the above objectives, the technical solution of the present invention is as follows.

[0007] The invention provides a risk assessment method for industrial by-product sodium hydrosulfide used in a mineral processing process. The method comprises the following steps: obtaining a risk assessment factor of the industrial by-product sodium hydrosulfide in a production process; performing a dose-response assessment on the risk assessment factor according to the amount of the industrial by-product sodium hydrosulfide used in the mineral processing process and the exposure pathway of the industrial by-product sodium hydrosulfide in the mineral processing process, obtaining concentration limits of the risk assessment factor in the industrial by-product sodium hydrosulfide under different exposure pathways, and taking the minimum concentration limit as a standard concentration limit; obtaining production conditions in the production process of the industrial by-product sodium hydrosulfide, sampling and analyzing the industrial by-product sodium hydrosulfide under different production conditions, so as to obtain the concentration of the risk assessment factor in the industrial by-product sodium hydrosulfide under different production conditions, and comparing the concentration with the standard concentration limit, so as to assess the risk of the industrial by-product sodium hydrosulfide used in the mineral processing process under different production conditions.

[0008] The invention mainly calculates the concentration limit of the risk assessment factor in the industrial by-product sodium hydrosulfide under different exposure pathways through a dose-response assessment method, and takes the minimum concentration limit as the standard concentration limit according to the risk maximization principle; and compares the concentration of the risk assessment factor in the industrial by-product sodium hydrosulfide under different production conditions with the standard concentration limit, so as to assess the risk of the industrial by-product sodium hydrosulfide under different production conditions before being used for mineral processing, so as to reduce the environmental risk and avoid the adverse effects on soil and groundwater caused by toxic and harmful substances brought in when the industrial by-product sodium hydrosulfide is used for mineral processing.

[0009] Preferably, the method for obtaining risk assessment factors in the production process of industrial by-product sodium hydrosulfide is as follows: according to the production process of industrial by-product sodium hydrosulfide, the pollutants in the industrial by-product sodium hydrosulfide are analyzed to obtain pollutant estimation results; volatile organic matter analysis and heavy metal element analysis are performed on the industrial by-product sodium hydrosulfide to determine the pollutants in the industrial by-product sodium hydrosulfide and obtain pollutant detection results; the pollutant estimation results and the pollutant detection results are analyzed to determine the key pollutants newly introduced in the industrial by-product sodium hydrosulfide as risk assessment factors.

[0010] In the present invention, the method for determining the key pollutants newly introduced in the industrial by-product sodium hydrosulfide is: analyzing the pollutant speculation results and the pollutant detection results to determine the key pollutants in the industrial by-product sodium hydrosulfide; comparing the key pollutants with the quality requirements of the 32% liquid specification in the GB / T 23937-2020 industrial sodium hydrosulfide standard to determine the key pollutants newly introduced in the industrial by-product sodium hydrosulfide. Preferably, the risk assessment factors are isobutanol, cresol and TOC.

[0011] Preferably, the method for obtaining the concentration limit of the risk assessment factor in industrial by-product sodium hydrosulfide under different exposure pathways is as follows: determining the amount of industrial by-product sodium hydrosulfide used in the mineral processing process; conducting an exposure assessment of the industrial by-product sodium hydrosulfide in the mineral processing process to determine the exposure pathway of the industrial by-product sodium hydrosulfide in the mineral processing process; conducting a dose-response assessment on the risk assessment factor based on the amount of industrial by-product sodium hydrosulfide used in the mineral processing process, the exposure pathway of the industrial by-product sodium hydrosulfide in the mineral processing process, and the biological predicted no-effect concentration under the corresponding exposure pathway, to obtain the concentration limit of the risk assessment factor in the industrial by-product sodium hydrosulfide under different exposure pathways.

[0012] Preferably, the exposure pathways are water environment, soil environment and oral ingestion; the method for determining the standard concentration limit is as follows: according to the calculation formula of the predicted no-effect concentration of organisms in the water environment and the calculation formula of the concentration limit of the risk assessment factor in the industrial by-product sodium hydrosulfide in the water environment, the concentration limit of the risk assessment factor in the industrial by-product sodium hydrosulfide in the water environment is calculated; according to the calculation formula of the predicted no-effect concentration of organisms in the soil environment and the calculation formula of the concentration limit of the risk assessment factor in the industrial by-product sodium hydrosulfide in the soil environment, the concentration of the risk assessment factor in the industrial by-product sodium hydrosulfide in the soil environment is calculated. limit; calculate the content limit of the risk assessment factor in industrial by-product sodium hydrosulfide ingested orally according to the calculation formula for the average daily oral intake dose of the human body, the calculation formula for the concentration limit of the risk assessment factor in industrial by-product sodium hydrosulfide in aquatic environment, and the calculation formula for the content limit of the non-carcinogenic risk assessment factor; compare the concentration limit of the risk assessment factor in industrial by-product sodium hydrosulfide in aquatic environment, the concentration limit of the risk assessment factor in industrial by-product sodium hydrosulfide in soil environment, and the content limit of the risk assessment factor in industrial by-product sodium hydrosulfide ingested orally, and obtain the minimum concentration limit as the standard concentration limit.

[0013] Preferably, the calculation formula for the predicted no-effect concentration of organisms in aquatic environments is: PENC 水 = ecoTox 水 / AF 水 ;in, PENC 水It indicates the predicted no-effect concentration for organisms in the aquatic environment; ecoTox 水 It indicates the ecotoxicological critical effect value of organisms in aquatic environment; AF 水 Represents the assessment coefficient in water environment. The concentration limit calculation formula of the risk assessment factor in industrial by-product sodium hydrosulfide in water environment is: C 水 = K 1× C i水 ;in, C 水 Indicates the concentration of risk assessment factors in the water environment; C i水 Indicates the content limit of risk assessment factor in industrial by-product sodium hydrosulfide in water environment. K 1 represents the evaluation coefficient in water environment; K 1 is determined by the ratio of the amount of sodium hydrosulfide added per ton of raw ore to the mass percentage of sodium hydrosulfide in industrial by-product sodium hydrosulfide and the mass percentage of tailings in raw ore.

[0014] Preferably, the calculation formula for the predicted no-effect concentration of organisms in the soil environment is: PENC 土壤 = Tox 土壤 / AF 土壤 ;in, PENC 土壤 It indicates the predicted no-effect concentration of organisms in soil environment; Tox 土壤 Indicates biologically effective ecotoxicity data in soil environment; AF 土壤 Represents the assessment coefficient in soil environment. The concentration limit calculation formula of the risk assessment factor in industrial by-product sodium hydrosulfide in soil environment is: C 土壤 = K 2× C i土壤 ;in, C 土壤 Indicates the concentration of risk assessment factors in the soil environment; C i土壤 Indicates the content limit of the risk assessment factor in sodium hydrosulfide solution. K 2 represents the evaluation coefficient under soil environment; K 2 is determined by the ratio of the amount of sodium hydrosulfide added per ton of raw ore, the mass percentage of sodium hydrosulfide in industrial by-product sodium hydrosulfide, the mass percentage of tailings in raw ore, and the density of industrial by-product sodium hydrosulfide.

[0015] Preferably, the calculation formula for the average daily oral intake dose for humans is: ;in, ADD It represents the average daily exposure to the pollutant; C 水 Indicates the concentration of risk assessment factors in the water environment; IR Indicates water intake; EF represents the frequency of exposure; ED Indicates the duration of exposure; BW represents weight; AT Indicates the average exposure time. The calculation formula for the content limit of the non-carcinogenic risk assessment factor is: or ;in, R i Indicates the content limit of the risk assessment factor in industrial by-product sodium hydrosulfide ingested orally; RfD o Indicates the reference dose for oral intake; TDI Indicates the tolerable daily intake.

[0016] Preferably, the method for assessing the risk of using industrial by-product sodium hydrosulfide in the mineral processing process under different production conditions is: obtaining the concentration of the risk assessment factor in the industrial by-product sodium hydrosulfide under different production conditions, and comparing it with the standard concentration limit, so as to obtain the production condition where the concentration of the risk assessment factor satisfies ≤ the standard concentration limit, and use it as the production control condition in the production process of industrial by-product sodium hydrosulfide to reduce the risk of using industrial by-product sodium hydrosulfide in the mineral processing process. Preferably, the production conditions in the production process of industrial by-product sodium hydrosulfide are: production load, production volume and condensation temperature.

[0017] Beneficial effects of the present invention: 1. The present invention mainly calculates the concentration limit of the risk assessment factor in industrial by-product sodium hydrosulfide under different exposure pathways through a dose-response assessment method, and takes the minimum concentration limit as the standard concentration limit according to the risk maximization principle; by comparing the concentration of the risk assessment factor in industrial by-product sodium hydrosulfide under different production conditions with the standard concentration limit, it is used to assess the risk of industrial by-product sodium hydrosulfide under different production conditions before being used for mineral processing, so as to reduce environmental risks and avoid the adverse effects of toxic and harmful substances on soil and groundwater brought in when industrial by-product sodium hydrosulfide is used for mineral processing.

[0018] 2. The present invention analyzes the types of pollutants that may be introduced when industrial by-product sodium hydrosulfide is used in the mineral processing process and simulates the exposure process of pollutants in the entire life cycle to obtain the concentration limits of risk assessment factors under different exposure pathways, and determines the production control conditions when the limit conditions are met, so as to provide process control guidance for by-product sodium sulfate production enterprises and provide pollutant control reference for utilization enterprises. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 This is a graph showing the relationship between isobutanol detection concentration and condensation temperature.

[0020] Figure 2 This is a graph showing the relationship between cresol detection concentration and condensation temperature.

[0021] Figure 3 This is the relationship between the theoretical concentration of cresol and the condensation temperature.

[0022] Figure 4 This is the relationship between the theoretical concentration of isobutanol and the condensation temperature. DETAILED DESCRIPTION

[0023] In order to make the purpose, technical solution and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with the embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention.

[0024] Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in the field without making any creative work shall fall within the scope of protection of the present invention.

[0025] The present invention identifies the pollutants brought into the industrial by-product sodium hydrosulfide according to the raw and auxiliary materials and reaction principles used in the process of by-product sodium hydrosulfide in the production of dye intermediates such as sodium hydrosulfide, butyl ammonium hydrosulfide and No. 25 hydrosulfide and pharmaceutical intermediates; then inquires and identifies the ecological and health toxicological data of each pollutant; calculates the concentration limit of each pollutant in different environmental media and the acceptable dose of the human body through the ecological and health toxicological data of each pollutant, including the biological predicted no effect concentration in the water environment, the biological predicted no effect concentration in the soil environment and the pollutant concentration limit in the tailings; then combines the sodium hydrosulfide with the exposure assessment formula used in the mineral processing process to calculate the concentration limit of each pollutant in the sodium hydrosulfide. Thus, various process parameters when the limit conditions are met are determined, and process guidance is provided for the production of industrial by-product sodium hydrosulfide, and technical reference is provided for the pollutant control of the use enterprise.

[0026] Gas Chromatography-Mass Spectrometry, English name Gas Chromatography-Mass Spectrometry, referred to as GC-MS. Chinese name: Inductively Coupled PlasmaOptical Emission Spectrometer, English name Inductively Coupled PlasmaOptical Emission Spectrometer, referred to as ICP-OES. Total Organic Carbon, English name Total Organic Carbon, referred to as TOC.

[0027] The technical solution of the present invention is further described below by means of specific examples. In the following examples, the methods described are conventional methods unless otherwise specified; the reagents and materials described are commercially available unless otherwise specified.

[0028] A risk assessment method for using industrial by-product sodium hydrosulfide in a mineral processing process comprises the following steps: Step 1, obtaining risk assessment factors in the production process of industrial by-product sodium hydrosulfide.

[0029] Step 1.1, according to the production process of industrial by-product sodium hydrosulfide, the pollutants in the industrial by-product sodium hydrosulfide are analyzed to obtain the pollutant estimation results; specifically: based on the raw and auxiliary materials and reaction principles of the by-product sodium hydrosulfide produced in the industrial production process, the pollutants in the industrial by-product sodium hydrosulfide are estimated.

[0030] The following is an example of a sodium hydrosulfide solution produced from a high-efficiency flotation agent sodium black medicine, butyl ammonium black medicine and No. 25 black medicine production project. The specific production processes are all prior art. The embodiments of the present invention are mainly to identify and determine the pollutants in the industrial by-product sodium hydrosulfide, so the parameters such as dosage are not described in detail.

[0031] Process 1: The production process of sodium black medicine includes the following steps: Step 1, synthesis section: add isobutyl alcohol and phosphorus pentasulfide into the synthesis reactor by vacuum extraction, heat to about 90°C with steam, stir the reaction materials to generate isobutyl black medicine acid, and the synthesized isobutyl black medicine acid is temporarily stored in the intermediate storage tank. The hydrogen sulfide gas generated in the synthesis section is used to produce sodium hydrosulfide solution. In the synthesis reaction process, the waste gas Gc is generated in the synthesis process of the synthesis reactor. 1-1 , the intermediate storage tank produces respiratory waste gas Gc 1-2 , mainly a small amount of unreacted isobutyl alcohol and H2S produced by the reaction, and waste packaging bags Sc produced during the use of phosphorus pentasulfide 1-1 .

[0032] Step 2, neutralization section: pump isobutyl black acid into the neutralization kettle, pass 30% liquid alkali and water, circulate cooling water in the jacket, react to pH = 8-9, and generate isobutyl sodium black liquid. During the neutralization reaction, a small amount of waste gas Gc generated in the synthesis section will be generated. 1-3 .

[0033] Step 3, compounding section: according to the demand, the sodium isobutyl black medicine liquid and the self-produced ethionamide are put into the compounding kettle to compound the required product sodium black medicine. Organic waste gas Gc is generated during the compounding process 1-4 .

[0034] Step 4, finished product packaging: put the finished sodium black medicine into the finished product tank area and put it into sealed barrels for finished product packaging.

[0035] Process 2: The production process of butyl ammonium black medicine includes the following steps: Step 1, synthesis section: add isobutyl alcohol and phosphorus pentasulfide into the synthesis reactor through vacuum extraction, heat to about 90°C with steam, and stir the reaction materials to generate diisobutyl dithiophosphoric acid, also known as isobutyl black medicine acid. The synthesized isobutyl black medicine acid is pumped into an intermediate storage tank for temporary storage. The hydrogen sulfide gas generated in the synthesis section is used to produce sodium hydrosulfide solution. Among them, the waste gas GC generated during the vacuum extraction of the synthesis reactor and the synthesis process 2-1 , the intermediate storage tank produces respiratory waste gas GC 2-2 , mainly a small amount of unreacted isobutyl alcohol and H2S produced by the reaction, and waste packaging bags SC produced during the use of phosphorus pentasulfide 2-1 .

[0036] Step 2, neutralization section: the synthesized isobutyl black medicine acid is pumped into the kneader, and the jacket is passed through with frozen brine to control the temperature at about 70°C. Liquid ammonia is passed into the kneader, and the liquid ammonia flow rate is set to 13.56m 3 / h, react to pH = 8 ~ 9, the reaction generates diisobutyl ammonium dithiophosphate, i.e. butyl ammonium black medicine solid powder product, the mixing and kneading process is closed.

[0037] Step 3, finished product packaging: The solid powder of ammonium butyl black medicine is bagged, and waste gas GC is generated when the mixer discharges the material. 2-3 , mainly dust and a small amount of unreacted ammonia. Among them, the waste gas containing alcohol and H2S in the synthesis reactor and intermediate storage tank during the vacuuming process is condensed, the frozen brine is about -5℃, about 70% of the isobutanol is recycled for production, and the sodium hydrosulfide produced after the H2S gas is absorbed by the tertiary alkali liquid is used as a by-product, and the remaining vacuum exhaust gas GC 2-1 , GC 2-2 and GC 2-3 Enter the workshop exhaust gas pretreatment device. The vacuum pump process generates vacuum pump wastewater WC 2-1 .

[0038] Process 3: The production process of No. 25 black medicine includes the following steps: Step 1, synthesis section: add cresol and phosphorus pentasulfide into the synthesis reactor through vacuum extraction, introduce steam and heat to about 100°C, stir the reaction materials to generate dimethylphenyl dithiophosphoric acid liquid, which is also the dark brown oily black medicine No. 25. The reaction is an exothermic reaction, and the temperature in the reactor is maintained at 120°C to 140°C to ensure that the reaction is complete to generate dimethylphenyl dithiophosphoric acid. The synthesized dark brown oily liquid material is pumped into an intermediate storage tank for cooling and temporary storage. The hydrogen sulfide gas generated in the reaction process is used to produce sodium hydrosulfide solution. Among them, the waste gas GC generated in the synthesis process of the synthesis reactor 3-1 , the intermediate storage tank produces respiratory waste gas GC 3-2, mainly a small amount of unreacted cresol and H2S produced by the reaction, and waste packaging bags SC produced during the use of phosphorus pentasulfide 3-1 .

[0039] Step 2, finished product packaging: put the finished product No. 25 black medicine into the finished product can and put it into a sealed barrel.

[0040] Process 4: The production process of industrial by-product sodium hydrosulfide includes the following steps: The hydrogen sulfide gas containing isobutanol and cresol produced in the production process of sodium black medicine, butyl ammonium black medicine and No. 25 black medicine is temporarily stored and buffered by a buffer device, and then passed through a condensation device with tap water at about 20℃, and a secondary condensation device with tap water at about 20℃. The isobutanol and cresol are recovered by secondary condensation and reused in production. At this time, the pollutants such as isobutanol and cresol in the hydrogen sulfide gas are reduced. Then the purified hydrogen sulfide gas is absorbed by a three-stage alkali solution with an alkali solution concentration of 30%. The volume of an alkali solution absorption tank is 4m 3 The amount of alkali solution added each time is about 1.4 tons to 1.6 tons, and sodium hydrosulfide solution is obtained in the third-stage alkali absorption kettle. The remaining vacuum exhaust gas enters the workshop exhaust gas pretreatment device.

[0041] The composition of industrial by-product sodium hydrosulfide was analyzed, and the composition of possible pollutants is shown in Table 1.

[0042] Table 1 Analysis of possible pollutant components

[0043] Step 1.2, performing volatile organic compound analysis and heavy metal element analysis on the industrial by-product sodium hydrosulfide, determining the pollutants in the industrial by-product sodium hydrosulfide, and obtaining the pollutant detection results.

[0044] The specific method is: collect 2 portions of sodium hydrosulfide solution as samples to be tested, numbered as sample 1 and sample 2, and perform GC-MS analysis and ICP-OES analysis on the two portions of sodium hydrosulfide solution respectively. GC-MS is used to perform qualitative and semi-quantitative detection of volatile and semi-volatile organic matter in sodium hydrosulfide solution, and semi-volatile organic matter is not detected. The quantitative analysis results of volatile organic matter are shown in Table 2. ICP-OES is used to perform quantitative detection of heavy metals in sodium hydrosulfide solution, see Table 3.

[0045] Table 2 Quantitative analysis results of volatile organic compounds

[0046] Table 3 Quantitative analysis results of heavy metal elements, unit: mg / kg

[0047] Note: ND means not detected; “ / ” means no data.

[0048] Step 1.3, analyze the pollutant inference results and pollutant detection results to determine the key pollutants newly introduced into the industrial by-product sodium hydrosulfide as risk assessment factors.

[0049] The method for determining the key pollutants newly introduced in industrial by-product sodium hydrosulfide is: analyze the pollutant inference results and pollutant detection results to determine the key pollutants in industrial by-product sodium hydrosulfide; compare the key pollutants with the quality requirements of the 32% liquid specification in the GB / T23937-2020 industrial sodium hydrosulfide standard to determine the key pollutants newly introduced in industrial by-product sodium hydrosulfide. The risk assessment factors are isobutanol, cresol and TOC.

[0050] First, based on the analysis of raw materials and their impurities, it is speculated that the pollutants that may be introduced include isobutyl alcohol, cresol, phosphorus pentasulfide, sodium hydroxide and heavy metals. According to the analysis of the process flow and production conditions, it is speculated that the pollutants that may be introduced include isobutyl black medicine acid, dimethyl phenol dithiophosphate, isobutyl sodium black medicine, dimethyl phenol sodium dithiophosphate and sodium sulfide. According to GC-MS and ICP-OES detection and analysis, the pollutants identified include barium, zinc, chromium, nickel, titanium, thallium, silver, arsenic, mercury, isobutyl alcohol and dimethyl trisulfide. According to the analysis of the process flow, the excluded pollutants include phosphorus pentasulfide, sodium hydroxide, dimethyl trisulfide, isobutyl black medicine acid, dimethyl phenol dithiophosphate, isobutyl sodium black medicine and dimethyl phenol sodium dithiophosphate. After the above screening, it was finally determined that the key pollutants in the industrial by-product sodium hydrosulfide include isobutyl alcohol, cresol, sodium sulfide, barium, zinc, chromium, nickel, titanium, thallium, silver, arsenic and mercury.

[0051] According to the above screening results, the key pollutants were compared with the quality requirements of the 32% liquid specification in the GB / T 23937-2020 industrial sodium hydrosulfide standard. The same key pollutants are sodium sulfide, barium, zinc, chromium, nickel, titanium, thallium, silver, arsenic and mercury; the newly introduced key pollutants are isobutanol and cresol. Since the production process of industrial by-product sodium hydrosulfide is mainly based on organic reactions, in order to comprehensively analyze the content of organic matter in industrial by-product sodium hydrosulfide, TOC is used to comprehensively evaluate the organic matter contained in industrial by-product sodium hydrosulfide. Therefore, the risk assessment factors of industrial by-product sodium hydrosulfide in the production process are determined to be isobutanol, cresol and TOC. Industrial by-product sodium hydrosulfide is sodium hydrosulfide solution.

[0052] Step 2: Based on the amount of industrial by-product sodium hydrosulfide used in the mineral processing process and the exposure pathway of the industrial by-product sodium hydrosulfide in the mineral processing process, a dose-response assessment is conducted on the risk assessment factor to obtain the concentration limit of the risk assessment factor in the industrial by-product sodium hydrosulfide.

[0053] Step 2.1, determine the amount of industrial by-product sodium hydrosulfide used in the mineral processing process.

[0054] Through the research and experiment on the mechanism of action of sodium hydrosulfide solution in the beneficiation process, taking chalcopyrite and pyrite as examples, considering that chalcopyrite has good self-induced flotation characteristics and pyrite has good sodium hydrosulfide induced flotation behavior, when the amount of sodium hydrosulfide is controlled at 400g / t~500g / t, the recovery rate of Co metal can be increased by 6.91%, and the annual income of Co metal can be increased by more than 240 tons. In summary, when sodium hydrosulfide solution is used for beneficiation, according to the principle of risk maximization, the amount of sodium hydrosulfide used per ton of mineral in the beneficiation process is 500g / t of original ore, the amount of tailings produced is 70% of the original ore, and the concentration of sodium hydrosulfide solution is calculated as 32%.

[0055] Step 2.2, conduct an exposure assessment of the mineral processing process for industrial by-product sodium hydrosulfide to determine the exposure pathways of the mineral processing process for industrial by-product sodium hydrosulfide.

[0056] According to the production process of sodium hydrosulfide for mineral processing, the environmental impact of the three wastes produced in the production process was analyzed to determine the exposure pathways of health hazards in the mineral processing process of industrial by-product sodium hydrosulfide.

[0057] Wastewater: The production wastewater generated by mineral processing is mainly mineral processing wastewater. The mineral processing wastewater can be recycled within the system. Except for some losses, new water needs to be supplemented as production water, and no production wastewater is discharged.

[0058] Waste gas: The main sources of waste gas pollution generated by mineral processing include dust from loading and unloading of raw ore and stacking, dust from crushing and screening, dust from transportation, etc. The main pollutants are particulate matter. No waste gas is generated after adding flotation agents.

[0059] Solid waste: The solid waste generated by mineral processing is mainly tailings, with a generation rate of 70% to 95% of the original ore. Tailings can be comprehensively utilized in the production of cement, etc. According to GB / T 39198-2020 General Solid Waste Classification and Code, mineral processing tailings belong to general solid wastes generated by the mining industry. Other tailings refer to some ores that cannot be used for production due to low content of useful target components produced by the sorting operation in mineral processing, as well as waste slag produced by the crushing and sorting process. According to GB 18599-2020 General Industrial Solid Waste Storage and Landfill Pollution Control Standards, tailings that cannot be comprehensively utilized are landfilled in general industrial solid waste landfills.

[0060] According to GB 18599-2020 General Industrial Solid Waste Storage and Landfill Pollution Control Standard, Class I general industrial solid waste, such as tailings, can be filled or backfilled in the goaf of mines, pits and other mining areas in the original mining area, and Class II general industrial solid waste is landfilled in Class II solid waste landfills. Class II solid waste landfills should use a single artificial composite lining as an anti-seepage lining. According to the principle of risk maximization, mineral processing tailings are filled or backfilled in goafs such as mines and pits as Class I general solid wastes. The toxic and harmful substances contained in the tailings may have an adverse impact on groundwater, surface water, soil, etc.

[0061] From the above analysis, it can be seen that when sodium hydrosulfide is used for mineral processing, it will not produce waste gas and wastewater related to it, but will produce solid waste tailings. When the tailings that cannot be comprehensively utilized are backfilled in the mine pit, they will enter the water body with rainwater after rain, and the toxic and harmful substances contained in them will mainly go to groundwater, surface water and soil. According to the main exposure pathways, the environmental hazard exposure pathway is water and soil, and the health hazard exposure pathway is oral, that is, drinking groundwater.

[0062] Therefore, the environmental hazards of industrial by-product sodium hydrosulfide used in the mineral processing process are exposed to groundwater, surface water and soil. According to the maximum risk, the evaluation is divided into two situations: one is that all the harmful substances in the sodium hydrosulfide solution enter the water, and the environmental hazard risk assessment of groundwater and surface water is carried out; the other is that all the harmful substances in the sodium hydrosulfide solution enter the soil, and the environmental hazard risk assessment of the soil is carried out.

[0063] The health hazard exposure route of the industrial by-product sodium hydrosulfide in the mineral processing process is that the harmful substances in the sodium hydrosulfide solution enter the groundwater and are then consumed by people.

[0064] In step 2.3, based on the amount of industrial by-product sodium hydrosulfide used in the mineral processing process, the exposure pathway of industrial by-product sodium hydrosulfide in the mineral processing process, and the predicted biological no-effect concentration under the corresponding exposure pathway, a dose-response evaluation is performed on the risk assessment factors to obtain the concentration limits of the risk assessment factors in industrial by-product sodium hydrosulfide under different exposure pathways, and the minimum concentration limit is used as the standard concentration limit.

[0065] The exposure pathways are water environment, soil environment and oral ingestion. The embodiment of the present invention mainly combines the exposure assessment formula used in the mineral processing process of sodium hydrosulfide to deduce the concentration limit of each pollutant in sodium hydrosulfide. The dose-response assessment includes environmental hazard characterization and health hazard characterization. According to the above analysis, the risk assessment scenario of sodium hydrosulfide solution is determined to be used for mineral processing. The evaluation principle is the principle of determining the source of the no-effect concentration. Calculate according to the following categories and select the minimum value as the final no-effect concentration: First, if the risk assessment factor has an execution standard, use the execution standard, and according to the principle of risk maximization, reverse the limit value in the sodium hydrosulfide solution; second, it can be directly found PNEC The risk assessment factor of the data is used to reverse the limit value in the sodium hydrosulfide solution according to the principle of risk maximization; thirdly, if the hazard factor has neither an implementation standard nor a PNEC Data, but toxicological data are sufficient to use dose-response calculations; fourth, TOC is used to calculate all organic matter. Among them, PNEC Indicates the biological predicted no-effect concentration. The ecological and health toxicological data of the risk assessment factors are analyzed to deduce the concentration limits of each pollutant in different environments and the acceptable dose for the human body, see Table 4.

[0066] Table 4 Ecological and health toxicological data of each pollutant in different environments

[0067] Note: “-” means no adverse reaction was detected or observed. LD 50 Indicates median lethal dose; LC 50 Indicates median lethal concentration; EC 50，48h It indicates the half effective concentration within a 48-hour period; NOEC 21d It represents the no-observed-effect concentration during the 21-day period; NOAEL 生育能力 It represents the highest concentration under exposure conditions without any observed adverse effects on fertility; NOAEL 一般毒性 It represents the highest concentration under exposure conditions at which no adverse effects are observed on general toxicity to organisms; NOAEL 后代 It represents the highest concentration under exposure conditions at which no adverse effects are observed on the offspring of the organism; PENC 淡水 It represents the predicted no-effect concentration for organisms in freshwater environments; PENC 海水 It represents the predicted no-effect concentration for organisms in the marine environment; PENC 污水处理厂It represents the predicted no-effect concentration of organisms in the wastewater treatment plant environment; PENC 土壤 It indicates the predicted no-effect concentration of organisms in the soil environment.

[0068] (1) Characterization of water environmental hazards: The risk assessment factors in sodium hydrosulfide solution were evaluated using the reference index limits in GB 3838-2002 Surface water quality environmental index standard, GB / T 14848-2017 Groundwater quality standard, and GB / T 5749-2022 Drinking water hygiene standard.

[0069] Table 5 Standard limits of risk assessment factors in water environment

[0070] Table 6 Ecotoxicological data of pollutants in water environment

[0071] As shown in Table 5, there are no corresponding standard limits for isobutanol and cresol. Therefore, based on the ecotoxicological key effect data of isobutanol and cresol in aquatic organisms in Table 6, the evaluation coefficient method is used to calculate the predicted no-effect concentration of organisms in the aquatic environment for risk characterization. The method of deriving the predicted no-effect concentration of organisms in the aquatic environment using the evaluation coefficient method is: divide the ecotoxicological key effect data of aquatic organisms determined by hazard identification by the evaluation coefficient to deduce PENC 水 .

[0072] The specific calculation formula is: PENC 水 = ecoTox 水 / AF 水 ;in, PENC 水 It indicates the predicted no-effect concentration of organisms in water environment, mg·L -1 ; ecoTox 水 Indicates the critical effect value of biological ecotoxicology in water environment, mg·L -1 ; AF 水 Indicates the evaluation coefficient in water environment. ecoTox 水 The median lethal concentration of the most sensitive species is usually used. LC 50 , effect concentration EC 50 or EC 10 , or no observed effect concentration NOEC And other representations. AF 水is based on ecoTox 水 Select and determine dimensionless. According to the above rules and calculation formula, calculate the risk assessment factor in sodium hydrosulfide solution. PENC 水 , see Table 7.

[0073] Table 7 Risk assessment factors in sodium hydrosulfide solution PENC 水 The estimated results

[0074] When sodium hydrosulfide solution is used for mineral processing, according to the principle of risk maximization, the amount of sodium hydrosulfide used is 500g / t of raw ore, the amount of tailings produced is 70% of the raw ore, and the concentration of sodium hydrosulfide solution is 32%. It is assumed that all the risk assessment factors in the sodium hydrosulfide solution enter the tailings. According to the principle of risk maximization, according to the leachate in the tailings entering the water body, the concentration limit calculation formula of the risk assessment factor in the industrial by-product sodium hydrosulfide in the water environment is: ;in, C 水 Indicates the concentration of risk assessment factor in water environment, mg / L; C i水 It indicates the content limit of risk assessment factor in industrial by-product sodium hydrosulfide in water environment, mg / L. K 1 represents the evaluation coefficient in water environment; K 1 is determined by the ratio of the amount of sodium hydrosulfide added per ton of raw ore to the mass percentage of sodium hydrosulfide in industrial by-product sodium hydrosulfide and the mass percentage of tailings in raw ore. 硫氢化钠 Indicates the amount of sodium hydrosulfide per ton of raw ore, g / t; Q 硫氢化钠溶液 It indicates the mass percentage of sodium hydrosulfide in industrial by-product sodium hydrosulfide, %; M 尾矿 It indicates the mass percentage of tailings to the original ore, %. C 水 According to the water quality standards found or PENC 水 Determine. According to the water quality standards or PENC 水 , substitute into the calculation formula C 水 =0.00223 C i水 The concentration limits of risk assessment factors in sodium hydrosulfide solution are calculated as shown in Table 8.

[0075] Table 8 Concentration limits of risk assessment factors for water environment when sodium hydrosulfide solution is used for mineral processing

[0076] (2) Characterization of soil environmental hazards: The risk assessment factors in sodium hydrosulfide solution were evaluated using the concentration limits in GB 36600-2018 Soil Environmental Quality - Risk Control Standard for Soil Pollution in Construction Land and GB / T 15618-2018 Soil Environmental Quality - Risk Control Standard for Soil Pollution in Agricultural Land.

[0077] After comparison, isobutanol and cresol have no corresponding soil concentration limits. Therefore, according to the trial provisions of Announcement No. 69 of 2020 on the technical guidelines for environmental and health hazard assessment of chemical substances, soil environmental hazard characterization usually adopts the phase equilibrium distribution method or the evaluation coefficient method to derive the predicted no-effect concentration of organisms in the soil environment, which is recorded as PENC 土壤 When effective ecotoxicity data for organisms in soil environments are unavailable, the phase equilibrium partition method shall be used for estimation; when limited effective ecotoxicity data for organisms in soil environments are available, the evaluation coefficient method shall be used for estimation.

[0078] According to the effective ecotoxicity data of isobutanol and cresol in soil environment in Table 4, the predicted no-effect concentration of organisms in soil environment was calculated by evaluation coefficient method for risk characterization; the specific calculation formula is: PENC 土壤 = Tox 土壤 / AF 土壤 ;in, PENC 土壤 It represents the predicted no-effect concentration of organisms in soil environment, mg·L -1 ; Tox 土壤 Indicates the effective ecotoxicity data of organisms in soil environment, mg·L -1 ; AF 土壤 Represents the evaluation coefficient in soil environment.

[0079] Table 9 Risk assessment factors in sodium hydrosulfide solution PENC 土壤 The estimated results

[0080] Note: “-” indicates not calculated or no estimated result.

[0081] When sodium hydrosulfide solution is used for mineral processing, according to the principle of risk maximization, the amount of sodium hydrosulfide used is 500g / t of raw ore, the amount of tailings produced is 70% of the raw ore, the concentration of sodium hydrosulfide solution is 32%, and the density is 1.22g / mL. Assuming that all the risk assessment factors in the sodium hydrosulfide solution enter the tailings, the tailings are landfilled in the mine pit, and after reclamation, the landfilled tailings are used as soil, then the calculation formula for the concentration limit of the risk assessment factor in the sodium hydrosulfide solution is: ; in, C 土壤 It indicates the concentration of risk assessment factor in soil environment, mg / kg; C i土壤 Represents the content limit of the risk assessment factor in sodium hydrosulfide solution, mg / L. K 2 represents the evaluation coefficient under soil environment; K 2 is determined by the ratio of the amount of sodium hydrosulfide added per ton of raw ore to the mass percentage of sodium hydrosulfide in industrial by-product sodium hydrosulfide, the mass percentage of tailings in raw ore, and the density of industrial by-product sodium hydrosulfide. 硫氢化钠 Indicates the amount of sodium hydrosulfide per ton of raw ore, g / t; Q 硫氢化钠溶液 It indicates the mass percentage of sodium hydrosulfide in industrial by-product sodium hydrosulfide, %; M 尾矿 Indicates the mass percentage of tailings to the original ore, %;ρ 硫氢化钠溶液 Represents the density of industrial by-product sodium hydrosulfide. C 土壤 According to the implementation standards or PENC 土壤 Sure.

[0082] Table 10 Concentration limits of risk assessment factors for soil environment when sodium hydrosulfide solution is used for mineral processing

[0083] (3) Characterization of dose-response health hazards.

[0084] On the basis of exposure assessment and toxicity assessment, the risk assessment model is used to calculate the risk value of a single pollutant through a single exposure pathway, the risk value of a single pollutant through all exposure pathways, and the risk value of all pollutants through all exposure pathways. The risk values ​​calculated by risk characterization include the carcinogenic risk value of a single pollutant, the total carcinogenic risk value of all pollutants of concern, the hazard entropy of a single pollutant with a non-carcinogenic risk value, and the hazard index of multiple pollutants of concern. Groundwater is set to be fully entered when it is drunk. According to the adult volume in the Population Exposure Parameter Manual, the total drinking water intake of urban and rural populations in 2002 was 1850 mL / d.

[0085] The formula for calculating the average daily oral intake of human body is as follows: ;in, ADD Indicates the average daily exposure to pollutants, mg kg -1 ·d -1 ; C 水 Indicates the concentration of risk assessment factor in water environment, mg / L; IR represents water intake, mL / d; EF represents the exposure frequency, d / a; ED represents the duration of exposure, a; BW Indicates weight, kg; AT represents the average exposure time, d.

[0086] The sodium hydrosulfide dosage is selected as 500g / t of original ore, the tailings generated are 70% of the original ore, and the concentration of the sodium hydrosulfide solution is 32%. According to the principle of risk maximization, it is assumed that all the risk assessment factors in the sodium hydrosulfide solution enter the tailings. According to HJ / T299-2007 Solid Waste Leaching Toxicity Leaching Method Sulfuric Acid and Nitric Acid Method, the process of leaching harmful components from the waste into the environment under the influence of acidic precipitation when the waste is not disposed of, stored or used on land after harmless treatment is simulated. The tailings are backfilled in the mine pit. According to risk maximization, it is assumed that the leachate enters the groundwater with rainwater, and the groundwater is directly consumed by people as drinking water. The concentration limit of the risk assessment factor in the groundwater is: .

[0087] choose IR =1850mL / d, EF =365d / year, ED =The average human lifespan is 70 years, BW =60kg, AT = the number of days in the average human lifespan of 70 years, then ADD The calculation formula is as follows: .

[0088] Isobutanol and cresol are not included in the list of carcinogens, so the carcinogenic risk is not considered. The calculation formula for the content limit of the non-carcinogenic risk assessment factor is: or ;in, R i Indicates the content limit of the risk assessment factor in industrial by-product sodium hydrosulfide ingested orally; RfD o Indicates the oral intake reference dose, mg pollutant kg -1 Weight·d -1 ; TDI Indicates the tolerable daily intake, mg kg BW -1·d -1 .

[0089] Table 11 Risk assessment factor content limits for oral intake of industrial by-product sodium hydrosulfide

[0090] Note: Acceptable health risk: The acceptable risk level for carcinogens is on the order of 10 -6 ~10 -4 Range: less than 10 -6 Indicates that the risk is not obvious; 10 -6 ~10 -4 Indicates risk; greater than 10 -4 Indicates a more significant risk; the acceptable risk index for non-carcinogenic substances should be less than 1.0.

[0091] Compare the concentration limits of risk assessment factors in industrial by-product sodium hydrosulfide in water environment, the concentration limits of risk assessment factors in industrial by-product sodium hydrosulfide in soil environment, and the content limits of risk assessment factors in industrial by-product sodium hydrosulfide taken orally, and obtain the minimum concentration limit as the standard concentration limit. Based on the above analysis, the most stringent limit is selected as the risk assessment limit requirement, and the risk assessment limits of sodium hydrosulfide solution are summarized in Tables 12 and 13.

[0092] Table 12 Concentration limits of environmental and health hazards of risk assessment factors, unit: mg / L

[0093] Table 13 Concentration limits for dose-response evaluation of risk assessment factors, unit: mg / L

[0094] Step 3, obtaining the production conditions in the production process of industrial by-product sodium hydrosulfide, and sampling and analyzing the industrial by-product sodium hydrosulfide under different production conditions to obtain the concentration of risk assessment factors in the industrial by-product sodium hydrosulfide under different production conditions, and comparing them with the standard concentration limits to evaluate the risk of using industrial by-product sodium hydrosulfide under different production conditions in the mineral processing process.

[0095] Product quality inspection factors: The product quality inspection factors of industrial by-product sodium hydrosulfide are determined as appearance and the mass fraction of sodium sulfide and sodium hydrosulfide.

[0096] Sampling frequency and cycle: According to the inspection rules in GB / T 23937-2020 Industrial Sodium Hydrosulfide, the same batch of products produced by the same manufacturer using the same materials and basically the same production conditions, or produced by the same team, are considered as one batch. One batch of sodium hydrosulfide solution is produced every day. According to the ledger statistics, the actual monthly production volume at the maximum production load since the trial production is about 8.7 tons / month. According to the inspection rules in GB / T 23937-2020 Industrial Sodium Hydrosulfide, the number of sampling units and the sampling method are determined in accordance with the provisions of GB / T 6678, GB / T 6679, and GB / T 6680. Mix at least 200g of liquid sample evenly and put it in a clean and dry sample bottle and label it. Sodium hydrosulfide solution is produced intermittently, with one batch produced every day. To ensure the representativeness of the collected samples, the sampling plan is shown in Table 14. The sampling location is the third-level alkali absorption kettle. The maximum monthly production of sodium hydrosulfide solution is 8.7 tons. Sampling was carried out at equal time intervals. The sampling frequency of sodium hydrosulfide solution is shown in Table 15.

[0097] Table 14 Sampling plan for sodium hydrosulfide solution

[0098] Table 15 Sampling frequency of sodium hydrosulfide solution

[0099] Note: The number of samples is 1+1, which means parallel samples were collected.

[0100] Evaluation limit: The evaluation limit includes product quality evaluation limit and risk assessment limit. The quality evaluation limit of industrial by-product sodium hydrosulfide is determined according to the quality requirements of 32% liquid specification in the GB / T 23937-2020 industrial sodium hydrosulfide standard, see Table 16. According to the exposure route, the environmental hazard characterization considers water and soil, and the health hazard characterization only considers oral. The concentration limits of risk assessment factors in industrial by-product sodium hydrosulfide are shown in Table 13. The concentration limits of risk assessment factors in Table 13 are used as standard concentration limits.

[0101] Table 16 Product quality limits of sodium hydrosulfide solution

[0102] Investigation of working conditions during sampling: During the risk rating and product quality sample collection, relevant production load, production volume, condensation temperature, etc. were investigated simultaneously. The condensation temperature of the production process of butyl ammonium black medicine, sodium black medicine, and No. 25 black medicine is shown in Table 17.

[0103] Table 17 Primary condensation / secondary condensation temperature in the production process of butyl ammonium black powder, sodium black powder, and No. 25 black powder / ℃

[0104] According to the working condition statistics, during the sampling period of sodium hydrosulfide solution, from 2024.5.29 to 2024.6.3 and from 2024.6.7 to 2024.6.10, the condensation temperature of hydrogen sulfide gas produced by butyl ammonium black medicine and sodium black medicine was relatively low, about 20°C, and frozen brine was used to condense the hydrogen sulfide gas.

[0105] The product quality test results of sodium hydrosulfide solution are shown in Table 18. The test data of risk assessment factors in sodium hydrosulfide solution are shown in Table 19 and Table 20. According to the test results, all five samples of sodium hydrosulfide solution tested met the quality requirements of the 32% liquid specification in the GB / T 23937-2020 industrial sodium hydrosulfide standard.

[0106] Table 18 Product quality test results of sodium hydrosulfide solution

[0107] Table 19 Test data of risk assessment factors in sodium hydrosulfide solution

[0108] Table 20 Analysis results of the test data of risk assessment factors in sodium hydrosulfide solution

[0109] According to the above test results, the concentrations of cresol and TOC in the sodium hydrosulfide solution do not exceed the relevant requirements of the risk assessment limit. According to the working condition statistics and the isobutanol test results, the isobutanol test data of the samples collected from 2024.5.29 to 2024.6.3 and 2024.6.7 to 2024.6.10 were low and did not exceed the risk assessment limit requirements. According to working condition statistics, the condensation temperature during the sampling period was about 20°C. The sodium hydrosulfide solution produced at this condensation temperature can meet the risk assessment limit requirements. According to Figure 1 When the condensation temperature is lower than 20℃, the isobutyl alcohol detection concentration is lower than the limit. According to the cresol detection results, the cresol detection results can meet the risk assessment limit requirements. Figure 2 It can be seen that when the condensation temperature is low, the detected concentration of cresol is lower.

[0110] In summary, the condensation temperature is an important parameter for the risk assessment factor in sodium hydrosulfide solution to meet the standard, and at 20 °C, isobutanol, cresol and TOC can meet the product quality requirements. Therefore, when producing sodium hydrosulfide solution, the condensation temperature of hydrogen sulfide gas must be strictly controlled below 20 °C.

[0111] Calculation of the content of risk assessment factors in sodium hydrosulfide solution: According to working condition statistics, during the collection of sodium hydrosulfide solution samples, sodium black medicine, butyl ammonium black medicine and No. 25 black medicine were all produced, and the production load of No. 25 black medicine was relatively low. When the secondary condensation temperature was low, the detection data of isobutanol, cresol and TOC were significantly reduced, indicating that the content of risk assessment factors in sodium hydrosulfide solution was closely related to the condensation temperature. The content of risk assessment factors in sodium hydrosulfide solution was calculated when No. 25 black medicine, sodium black medicine and butyl ammonium black medicine were produced.

[0112] The content of cresol was calculated as follows: ; ;in, C 甲酚 It represents the theoretical calculated value of cresol when only No. 25 black medicine is produced; C 甲酚检测 Indicates the detection data of cresol; A 25号黑药生产的硫氢化钠 Indicates the amount of sodium hydrosulfide solution produced by No. 25 black medicine; A 硫氢化钠 Indicates the production of sodium hydrosulfide solution; A 25号黑药 represents the production of No. 25 black medicine; 56 represents the molar mass of sodium hydrosulfide; 311 represents the molar mass of No. 25 black medicine.

[0113] Calculation of isobutanol content: ;in, C 异丁醇 It represents the theoretical calculated value of isobutanol when only sodium black medicine and butyl ammonium black medicine are produced; C 异丁醇检测 Indicates the detection data of isobutanol.

[0114] Table 21 Data on toxic and hazardous substances in sodium hydrosulfide solution

[0115] Note: Theoretical calculation - cresol is the theoretical calculation result of the toxic and harmful factors in the sodium hydrosulfide solution when only No. 25 black medicine is produced. Theoretical calculation - isobutyl alcohol is the toxic and harmful factors in the sodium hydrosulfide solution when only butyl ammonium / sodium black medicine is produced.

[0116] When only No. 25 black medicine is produced, the toxic and harmful factor in the sodium hydrosulfide solution is cresol. After calculation, there is a situation where cresol exceeds the risk assessment limit. According to the working condition statistics, combined with Figure 3For samples that exceed the standard, the condensation temperature of hydrogen sulfide gas is relatively high, and the cresol recovery effect is not good. According to the annual production volume of butyl ammonium black medicine, sodium black medicine, and No. 25 black medicine and the company's sales, there is no limit to the production of only No. 25 black medicine. If the company only produces No. 25 black medicine, the secondary condensation temperature must be controlled below 20°C when producing sodium hydrosulfide solution. When only butyl ammonium / sodium black medicine is produced, the toxic and harmful factor in the sodium hydrosulfide solution is isobutanol. Figure 4 , it is calculated that when the condensation temperature is 20 ℃, isobutanol will not exceed the risk assessment limit.

[0117] Production condition analysis: According to the condition statistics during the identification period, isobutyl alcohol, cresol, and TOC test results, combined with the theoretical calculated concentrations of cresol and isobutyl alcohol under extreme conditions, at a condensation temperature of 20°C, each risk assessment factor can meet the product quality requirements and risk assessment limit requirements. Therefore, the production conditions of sodium hydrosulfide solution must meet the conditions of Table 22. The harmful components in the sodium hydrosulfide solution meet the environmental risk control requirements, and the industrial by-product sodium hydrosulfide can be used in the mineral processing industry.

[0118] Table 22 Production control conditions of sodium hydrosulfide solution

[0119] At the same time, the industrial by-product sodium hydrosulfide should be stored temporarily to prevent pollution to the soil and groundwater. The limit values ​​of each pollutant are determined as follows: isobutyl alcohol 493mg / L, cresol 31mg / L, TOC 2.24×10 3 mg / L.

[0120] The above are only preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A risk assessment method for using industrial by-product sodium hydrosulfide in a mineral processing process, characterized in that: The following steps are involved: Obtain risk assessment factors for industrial by-product sodium hydrosulfide in the production process; According to the amount of industrial by-product sodium hydrosulfide used in the mineral processing process and the exposure pathway of industrial by-product sodium hydrosulfide in the mineral processing process, a dose-response evaluation was conducted on the risk assessment factors to obtain the concentration limits of the risk assessment factors in industrial by-product sodium hydrosulfide under different exposure pathways, and the minimum concentration limit was used as the standard concentration limit; The production conditions in the production process of industrial by-product sodium hydrosulfide are obtained, and sampling and analysis of industrial by-product sodium hydrosulfide under different production conditions are carried out to obtain the concentration of risk assessment factors in industrial by-product sodium hydrosulfide under different production conditions, and compare them with the standard concentration limits to evaluate the risk of using industrial by-product sodium hydrosulfide under different production conditions in the mineral processing process.

2. The method for risk assessment of industrial by-product sodium hydrosulfide in a mineral processing process according to claim 1, characterized in that: The method for obtaining the risk assessment factor in the production process of industrial by-product sodium hydrosulfide is as follows: According to the production process of industrial by-product sodium hydrosulfide, the pollutants in industrial by-product sodium hydrosulfide are analyzed and the pollutant inference results are obtained; Conduct volatile organic compound analysis and heavy metal element analysis on industrial by-product sodium hydrosulfide to determine the pollutants in the industrial by-product sodium hydrosulfide and obtain the pollutant detection results; The pollutant speculation results and pollutant detection results were analyzed to determine the key pollutants newly introduced into the industrial by-product sodium hydrosulfide as risk assessment factors.

3. The method for risk assessment of industrial by-product sodium hydrosulfide for mineral processing according to claim 2, characterized in that: The risk assessment factors are isobutanol, cresol and TOC.

4. The method for risk assessment of industrial by-product sodium hydrosulfide for mineral processing according to claim 1, characterized in that: The method for obtaining the concentration limit of the risk assessment factor in industrial by-product sodium hydrosulfide under different exposure pathways is as follows: Determine the amount of industrial by-product sodium hydrosulfide used in the mineral processing process; Exposure assessment of industrial by-product sodium hydrosulfide in the mineral processing process to determine the exposure pathways of industrial by-product sodium hydrosulfide in the mineral processing process; Based on the amount of industrial by-product sodium hydrosulfide used in the mineral processing process, the exposure pathways of industrial by-product sodium hydrosulfide in the mineral processing process, and the predicted biological no-effect concentration under the corresponding exposure pathways, a dose-response evaluation was conducted on the risk assessment factors, and the concentration limits of the risk assessment factors in industrial by-product sodium hydrosulfide under different exposure pathways were obtained.

5. The method for risk assessment of industrial by-product sodium hydrosulfide for mineral processing according to claim 4, characterized in that: The exposure routes are water environment, soil environment and oral ingestion; The standard concentration limit is determined as follows: According to the calculation formula of biological predicted no-effect concentration in water environment and the calculation formula of concentration limit of risk assessment factor in industrial by-product sodium hydrosulfide in water environment, the concentration limit of risk assessment factor in industrial by-product sodium hydrosulfide in water environment is calculated; According to the calculation formula of biological predicted no-effect concentration in soil environment and the calculation formula of concentration limit of risk assessment factor in industrial by-product sodium hydrosulfide in soil environment, the concentration limit of risk assessment factor in industrial by-product sodium hydrosulfide in soil environment is calculated; Based on the calculation formula for the average daily oral intake dose of the human body, the calculation formula for the concentration limit of the risk assessment factor in industrial by-product sodium hydrosulfide in the water environment, and the calculation formula for the content limit of the non-carcinogenic risk assessment factor, the content limit of the risk assessment factor in the industrial by-product sodium hydrosulfide taken orally is calculated; Compare the concentration limits of risk assessment factors in industrial by-product sodium hydrosulfide in water environment, the concentration limits of risk assessment factors in industrial by-product sodium hydrosulfide in soil environment, and the content limits of risk assessment factors in industrial by-product sodium hydrosulfide ingested orally, and obtain the minimum concentration limit as the standard concentration limit.

6. The method for risk assessment of industrial by-product sodium hydrosulfide for mineral processing according to claim 5, characterized in that: The formula for calculating the predicted no-effect concentration for organisms in aquatic environments is: PENC 水 = ecoTox 水 / AF 水 ； in, PENC 水 It indicates the predicted no-effect concentration for organisms in the aquatic environment; ecoTox 水 It indicates the ecotoxicological critical effect value of organisms in aquatic environment; AF 水 It represents the evaluation coefficient in water environment; The concentration limit calculation formula for the risk assessment factor in industrial by-product sodium hydrosulfide in water environment is: C 水 = K 1× C i水 ； in, C 水 Indicates the concentration of risk assessment factors in the water environment; C i水 Indicates the content limit of risk assessment factor in industrial by-product sodium hydrosulfide in water environment. K 1 represents the evaluation coefficient in water environment; K 1 is determined by the ratio of the amount of sodium hydrosulfide added per ton of raw ore to the mass percentage of sodium hydrosulfide in industrial by-product sodium hydrosulfide and the mass percentage of tailings in raw ore.

7. The method for risk assessment of industrial by-product sodium hydrosulfide for mineral processing according to claim 6, characterized in that: The formula for calculating the predicted no-effect concentration for organisms in soil environments is: PENC 土壤 = Tox 土壤 / AF 土壤 ； in, PENC 土壤 It indicates the predicted no-effect concentration of organisms in soil environment; Tox 土壤 Indicates biologically effective ecotoxicity data in soil environment; AF 土壤 represents the evaluation coefficient under soil environment; The concentration limit calculation formula for the risk assessment factor in industrial by-product sodium hydrosulfide in soil environment is: C 土壤 = K 2× C i土壤 ； in, C 土壤 Indicates the concentration of risk assessment factors in the soil environment; C i土壤 Indicates the content limit of the risk assessment factor in sodium hydrosulfide solution. K 2 represents the evaluation coefficient under soil environment; K 2 is determined by the ratio of the amount of sodium hydrosulfide added per ton of raw ore, the mass percentage of sodium hydrosulfide in industrial by-product sodium hydrosulfide, the mass percentage of tailings in raw ore, and the density of industrial by-product sodium hydrosulfide.

8. The method for risk assessment of industrial by-product sodium hydrosulfide for mineral processing according to claim 7, characterized in that: The formula for calculating the average daily oral intake of human body is: ； in, ADD It represents the average daily exposure to the pollutant; C 水 Indicates the concentration of risk assessment factors in the water environment; IR Indicates water intake; EF represents the frequency of exposure; ED Indicates the duration of exposure; BW represents weight; AT represents the average exposure time; The calculation formula for the content limit of non-carcinogenic risk assessment factors is: or ; in, R i Indicates the content limit of the risk assessment factor in industrial by-product sodium hydrosulfide ingested orally; RfD o Indicates the reference dose for oral intake; TDI Indicates the tolerable daily intake.

9. The method for risk assessment of industrial by-product sodium hydrosulfide for mineral processing according to claim 1, characterized in that: The risk assessment method for using industrial by-product sodium hydrosulfide in the mineral processing process under different production conditions is: The concentration of risk assessment factors in industrial by-product sodium hydrosulfide under different production conditions is obtained and compared with the standard concentration limits to obtain production conditions where the concentration of risk assessment factors meets the standard concentration limit, which are used as production control conditions in the production process of industrial by-product sodium hydrosulfide to reduce the risk of using industrial by-product sodium hydrosulfide in the mineral processing process.

10. The method for risk assessment of industrial by-product sodium hydrosulfide in a mineral processing process according to claim 1, characterized in that: The production conditions in the production process of industrial by-product sodium hydrosulfide are: Production load, generation and condensing temperature.

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